Progress 10/01/19 to 09/30/20
Outputs
Progress Report Objectives (from AD-416): This research will provide basic and applied information for the development and transfer of sustainable and environmentally acceptable methods and technologies for management of insect pests of temperate tree fruit crops. The objectives are: Objective 1: Develop new knowledge of the behavior, physiology, ecology, and biochemistry of insect pests and their natural enemies to suggest novel approaches to pest management and improve the use of existing methods, with focus on pest-host plant interactions of pear psylla and brown marmorated stink bug, pest-microbe interactions of codling moth and spotted wing drosophila, ecological and physiological criteria that limit pest distribution and abundance, and the functionality of codling moth receptors. Subobjective 1A. Determine and characterize interactions between pear trees and pear psylla and between the brown marmorated stink bug (BMSB) and preferred host plants. Subobjective 1B. Determine if volatiles emanating from microbial species found in the honeydew of aphids, mealybugs and psyllids are attractive to natural enemies. Subobjective 1C. Determine factors affecting pupal mortality and adult emergence of western cherry fruit fly (WCFF) in the field. Sub-objective 1D. Determine the upper and lower thermal limits for metabolism of different life stages of codling moth (CM), apple maggot (AM), and WCFF. Subobjective 1E. Develop a CRISPR/Cas9 gene knock out system to determine functions of proteins key to CM reproduction and development. Subobjective 1F: Determine undescribed cryptic species and undocumented range expansions of the community of minute pirate bugs in orchards and other habitats. Objective 2: Develop alternatives to fumigation to meet quarantine restrictions for pest insects in exported fruits, with focus on developing codling moth detector technology and ecological niche modeling to determine limits to the establishment and spread of quarantined insect pests. Subobjective 2A: Identify biochemical markers for apple fruit infested with CM larvae, in support of effort to develop detector technology. Subobjective 2B: Improve ecological niche models for the potential of tree fruit pests of quarantine concerns to establish and spread in potential new export markets. Objective 3: Develop and improve methods to reduce pesticide use and develop alternatives to pesticides, with focus on identifying and applying semiochemicals for pest management, and improved efficacy of natural enemies through application of foods and feeding attractants, and improvement of pear psylla control through induced or systemic acquired resistance in pear to psylla. Subobjective 3A. Develop an attract-and-kill approach for management of codling moth and leafrollers. Subobjective 3B. Improve efficacy of natural enemies through application of foods and feeding attractants. Subobjective 3C. Determine field temperature influences on the efficacy of the insecticide spinosad and Delegate for management of WCFF. Subobjective 3D. Improve pear psylla control through induced or systemic acquired resistance. Subobjective 3E. Evaluate the use of microbial-based feeding attractants for management of codling moth. Approach (from AD-416): 1A. Plant resistance to pear psylla will be characterized using greenhouse and biochemical assays and electrical penetration graphs. Host preferences by brown marmorated stink bug will be assessed by determining patterns of host plant use in non-crop landscapes. Stink bug attraction to host odor will be tested using a laboratory olfactometer. 1B. To develop methods of recruiting natural enemies to orchards, microbes present in aphid and pear psylla honeydew will be identified, and odors emanating from honeydew-associated microbes will be tested for attractiveness to natural enemies. 1C. Western cherry fruit fly adult emergence will be compared from soils with varying moisture and cover to determine whether fruit fly infestations in orchards can emanate from trees located in unmanaged habitats with dry soil surfaces. 1D. Data from differential scanning calorimetry and laboratory assays will provide estimates of metabolic thermal limits for codling moth, apple maggot, and western cherry fruit fly to determine the likelihood for these pests to establish and spread in new geographies. 1E. A CRISPR/Cas9 gene knock out system will be used to determine the function of proteins key to codling moth reproduction and development in support of work to develop species-specific behavioral and physiological modifying analogs for use in pest management. 1F. To improve conservation biological control in orchards, undescribed cryptic species and undocumented range expansions of minute pirate bugs in orchards and other habitats will be described based on morphometric analyses and molecular genetics. 2A. In support of efforts to develop technology to detect codling moth infestations in stored fruit, biochemical markers for infested apples will be identified using GC-MS, and laboratory studies will be used to determine how long marker chemicals are emitted from infested fruit. 2B. Experiments conducted in environmental chambers will be used to determine the effects of tropical and sub-tropical climates and photoperiods on the growth and development of codling moth, western cherry fruit fly, and apple maggot. Data will be used to improve ecological niche models for tree fruit pests of quarantine concerns to estimate the risk for these pests to establish and spread in export markets. 3A. New attractant blends will be developed as an attract-and-kill or mass trapping approach for management of codling moth and leafrollers. 3B. Plant-based attractive lures and food provisioning will be tested as attract-and-retain method of improving biological control in orchards. 3C. Effects of temperature on the efficacy of the insecticides Spinosad and Delegate for management of western cherry fruit fly will be determined using laboratory assays. 3D. Greenhouse assays and field studies will be used to test whether elicitors of host plant defenses can be used for the control of pear psylla. 3E. Laboratory studies will be performed to determine whether the addition of different yeast species with cane sugar stimulate codling moth feeding and increase the efficacy of ingested microbial or chemical insecticides against codling moth. This is the final report for project 2092-22430-002-00-D, ⿿New Technologies and Strategies to Manage the Changing Pest Complex on Temperate Tree Fruits, which is set to expire on October 25, 2020. The project was subject to substantial personnel changes including 3.5 scientist vacancies with expertise in chemical ecology, biological control, and insect genetics, and one new scientist hired with expertise in biological control. Progress was made for all 3 objectives despite these critical vacancies. In support of Objective 1, research was conducted to improve knowledge of behavior, physiology, ecology, and biochemistry of key insect pests - brown marmorated stink bug, pear psylla, western cherry fruit fly, Asian giant hornet, and codling moth - and their key natural enemies. Reserch on Sub-objective 1A focused on the Brown marmorated stink bug which was recently introduced to the Pacific Northwest. Natural and suburban vegetation was sampled to monitor the spread of this invasive insect in eastern Washington. Distributions remained primarily urban during the sampling period, while most stink bugs present in non- agricultural areas were collected from succulent or fruiting plants. Native stink bugs collected during these surveys were catalogued to provide a resource for examining how the invasion of brown marmorated stink bug impacts native insect populations. Additional research on Sub-objective 1A focused on developing greater knowledge of the overwintering biology of pear psylla with the goal of better managing early-season infestations. A method was developed to identify the dietary history of psylla by sequencing plant DNA found in the insect⿿s gut. This information can then be used to identify which non- crop shelter plants are most likely to be sources of overwintered pear psylla arriving in orchards in early spring. This method is being adapted to study the landscape-movements of leafhopper vectors of X-disease phytoplasma and provided justification for an objective of the new project plan. In a subordinate project, changes in transcriptome-wide gene expression are being analyzed to better understand the genetic basis and timing for changes in pear psylla biology occurring during winter and spring. For Sub-objective 1B, research focused on the identification of attractants for generalist natural enemies which would enable the development of lures to attract predators to infestations within orchards. Research was initiated to determine whether volatiles emanating from microbial species growing on the honeydew of aphids are attractive to natural enemies. Field surveys revealed at least 40 bacterial species within 16 genera growing on aphid honeydew in apple and pear orchards, and that several species of parasitoid wasps were attracted to volatiles produced by these bacteria. For Sub-objective 1C, research focused on the Western cherry fruit fly, a major pest of cherry, which develops within fruit but pupates in soil. Research assessed the ability of the western cherry fruit fly to survive in dry soils and showed that fly pupae survived equally well in irrigated and unirrigated bare soils but suffered relatively high mortality in unirrigated grass-covered soils. These results suggest that unirrigated, grass-covered soils or mulch barriers in mid- and late-summer could reduce fly survival, thus suppressing fly abundance. A related study is examining the effects of irrigation and soil composition on survival of western cherry fruit fly pupae. Results are showing that variations in sand, silt, and clay can impact when and how many western cherry fruit flies emerge. Collectively, these results will allow researchers to better predict the types of habitats and climates that are most susceptible to infestation by western cherry fruit fly. Sub-objective 1D continued to evaluate the upper and lower thermal limits of all developmental stages of the codling moth, apple maggot, and western cherry fruit fly which were determined using differential scanning calorimetry. In support of Sub-objective 1E, research continued to investigate the function of codling moth genes, which is challenging due to the ineffectiveness of standard methods for functional genomics of moths. A CRISPR-Cas9 genome editing system was developed for codling moth to study protein function. After optimizing this system by editing a male dosage compensation protein gene, the tool was used to study the function of an odorant receptor gene used by males to locate females for mating. Unexpectedly, the knock-down of this odorant receptor in females caused mated females to lay unviable eggs. Subsequent experiments showed that this odorant receptor, which was previously only known to be expressed in male antennae, was also expressed in the female abdomen tip. These results suggest that this odorant receptor has a previously unknown role in signaling to females that they have mated. The validation of CRISPR- Cas9 gene editing tool for codling moth provided justification for an objective in the new project plan. For Sub-objective 1F, morphological, behavioral, and molecular genetic techniques were used to show that the minute pirate bug complex in western North America includes four described native species and six previously unknown species. The morphological data were used to develop a dichotomous key for identifying described and undescribed species. Field- collecting of specimens from multiple geographic regions combined with examination of over 3,000 museum-housed specimens was used to develop distribution maps based upon over 600 unique geographic records. These data were used to define each species⿿ known current distribution in western North America. Geographic and biological data, combined with the dichotomous key, provide growers and pest control advisors the tools needed to identify species of minute pirate bugs common in orchards of western North America. That information in turn will allow growers to more effectively incorporate biological control considerations into pest management decisions. In a subordinate project related to Objective 1, trapping methods were tested to monitor adult Trechnites populations and methods for detecting cryptic parasitoids were developed. Work was initiated to correlate adult population estimates with parasitism rates of pear psylla using these new methods. A method developed for obtaining large numbers of Trechnites from orchards will assist future work to determine pesticide non-target effects on Trechnites and improve pest management decisions. This research provided the basis for an objective in the new project plan. Other related subordinate projects compared non-target effects of common insecticides, fungicides, and acaricides on two predatory mites and used gut content analysis to evaluate seasonal changes in dietary breadth of predatory mites. In yet another subordinate project, studies were initiated to identify attractants for the newly introduced Asian giant hornet and to develop tools to detect and monitor the spread of this pest. In support of Sub-objective 2B, research was conducted to improve ecological niche models used to determine the limits to establishment and spread of quarantined insect pests. In a subordinate project, ecological niche modeling for 16 species of tree fruit pests of potential risk for movement from Canada to Washington via transport of municipal green waste revealed that several of these pests pose a significant risk to establish and spread in central Washington. These data will aid USDA-Animal Plant Health Inspection Service and Washington State Department of Agriculture in establishing guidelines for proposed shipments of municipal waste from Canada to the United States. For Objective 3, research was conducted to develop and improve use of alternatives to conventional pesticides. Sub-objective 3A focused on identifying volatile compounds that would be attractive to both sexes of moths and lead to the development of an effective attract and kill approach. Lures emitting plant-based kairomones that are highly attractive to both sexes of codling moth and leafrollers were developed and are a being tested by private companies for use in attract and kill management approaches. Sub-objective 3B evaluated three commercially available natural enemy food product supplements (Typha pollen, brine shrimp cysts, and Ephestia kuehniella eggs) were tested as potential food supplements for two predatory mite species. Initial results provided a foundation for an objective of the new project plan to devise ways to retain predators within orchards. Sub-objective 3C examined whether temperature alters the efficacy of the insecticides spinosad and Delegate for management of western cherry fruit fly. Results of laboratory assays were mixed and showed that the increased activity of western cherry fruit fly at higher temperatures caused them to be killed more quickly by both insecticides, but also resulted in greater oviposition rates. In contrast, the efficacy of the conventional pesticide, malathion, was not affected by temperature. The management of western cherry fruit fly could be improved by using increasing rates of spinosad or Delegate with increasing temperatures. For Sub-objective 3D, laboratory and field studies showed that several commercially available elicitors of acquired plant defenses reduce populations of pear psylla suggesting that the use of these elicitors for management of fire flight may also contribute to the management of pear psylla. Results from a subordinate project demonstrated that foliar applications of the alternative dietary sweetener, erythritol, deters settling and oviposition by pear psylla and reduces pear psylla survival. Erythritol also caused increased mortality of mite pests but had negative non-target effects on a predatory mite. These findings show that erythritol could be developed into a safe and effective tool for insect management. Accomplishments 01 Identifying diagnostic genetic markers for cryptic invasive agricultural pests. The apple maggot fly is an important quarantine pest of apples in the Pacific Northwest of the United States that is monitored using traps. The similar-looking snowberry maggot fly is frequently caught on these traps and can be mistaken for apple fly, which could lead to unjustified quarantines. Researchers at the USDA laboratory in Wapato, Washington, in collaboration with researchers at the University of Notre Dame, Indiana, Wayne State University, Detroit, Michigan, and McGill University, Canada, developed inexpensive, quick and reliable methods for discriminating the two fly species. A simple and cost-effective diagnostic approach using Illumina sequencing of double digest restriction-site associated DNA markers was developed. In addition, a diagnostic test based on agarose gel electrophoresis of restriction enzyme-digested polymerase chain reaction amplification products was able to distinguish the fly species. Results are important in that they present an effective strategy for apple maggot and are transferable to other cryptic pests. 02 Non-target effects of common orchard pesticides on a predatory mite. The non-target effects of pesticides on a common orchard predatory mite, Galendromus occidentalis, are well-described and used by orchardists to conserve this predator to prevent disruption of mite biological control. Another predatory mite, Amblydromella caudiglans, has also become common in apple orchards in recent years, but there is almost no research describing its pesticide sensitivity. Researchers at the USDA in Wapato, Washington in collaboration with scientists at Washington State University documented the non-target effects of common orchard insecticides and fungicides to Amblydromella. This information allows for modification of current recommendations to growers regarding which pesticides are least likely to disrupt mite biological control, which in turn will reduce the number of miticide applications they need to make each year. 03 Food supplements for improving biological control. Natural enemies may find it difficult to survive in orchards when pest populations are low and therefore cannot respond quickly to growing pest populations. Generalist natural enemies, some of which feed on non-pest resources (e. g. flower pollen, non-pest insects), may use these resources in times when other prey (pests) are scarce, which allows them to remain in the orchard even when pests are not present. Researchers at the USDA in Wapato, Washington, examined the ability of two predatory mites to reproduce and complete development on Typha pollen, brine shrimp cysts, and Ephestia kuehniella eggs, which are commercially available food supplement products. Neither predatory mite could consume Ephestia kuehniella eggs, but one species could complete development and reproduce on the pollen and cysts. Future work will examine the potential of these food products to boost populations of predatory mites in the field and to encourage grower-released natural enemies to remain in the orchard where they are released. 04 Rapid and repeatable host plant shifts drive reproductive isolation following a recent human-mediated introduction of the apple maggot fly. Apple maggot fly is a quarantine pest of apple in the western United States. Understanding the effects of host-shifting by flies as a mechanism for fly diversification is poorly understood. ARS researchers in Wapato, Washington, and Hilo, Hawaii, in collaboration with researchers at the University of Notre Dame, Wayne State University, Binghamton University, and Western Washington University, tested for genetic differentiation among apple maggot flies infesting apple and black and ornamental hawthorn fruit co-occurring at three sympatric sites. Evidence was found that populations of the three host- associations are genetically differentiated at the local level, indicating that partial reproductive isolation has evolved in the western United States. Results suggest that conditions suitable for initiating host-associated divergence may be common in nature, allowing for the rapid evolution of new host races when ecological opportunity arises. 05 Morphological and molecular genetic tools show that species diversity within the minute pirate bug complex of western North America is considerably larger than previously appreciated. Making full use of biological control opportunities in orchards requires tools for identifying predatory species of importance. Researchers at the USDA laboratory in Wapato, Washington, showed that the minute pirate bug (Orius) complex in western North America comprises at least ten native species instead of the four species commonly accepted in taxonomic treatments of this group, due to the discovery of previously unknown and undescribed species virtually identical in appearance to described species. Morphological, behavioral, and molecular genetic tools were employed in developing a dichotomous key to the ten species, allowing correct identification of species occupying agricultural and other habitats of western North America. Biological and geographic data collected during this research, when combined with these dichotomous keys, will allow fruit growers and pest control advisors to more effectively weigh the potential importance of these sources of biological control as they choose among different pest control options. 06 The artificial sweetener, erythritol, is insecticidal to pear psylla. Pear psylla is a key pest of commercial pear that requires repeated applications of insecticides to manage. New management tools are needed to reduce the risk that pear psylla populations will develop resistance to current insecticides. The artificial sweetener, erythritol, is non- toxic to humans but is insecticidal when ingested by certain insects. Researchers at the USDA laboratory in Wapato, Washington, and Heritage University in Toppenish, Washington, examined whether erythritol is also lethal to pear psylla. Results of laboratory and field experiments showed that treatment of pear with 20% erythritol causes 60-80% mortality of pear psylla nymphs and adults. These findings demonstrate that erythritol could be developed into a safe and effective tool for the management of pear psylla. 07 Methods for monitoring Trechnites, a key parasitoid of pear psylla. Pear psylla, the key insect pest of pear, is primarily controlled by pesticides while biological control by natural enemies remains underutilized. This is due in part to a poor understanding of the biology of its most important natural enemy, the parasitoid Trechnites spp. Researchers at the USDA in Wapato, Washington, in collaboration with scientists at Washington and Oregon State Universities, determined that screened sticky cards and custom-designed 3D-printed traps are effective methods for monitoring adult Trechnites and are superior to the traditional methods of monitoring by unscreened sticky card or beat tray. Additionally, the team determined that Trechnites parasitism levels can be monitored by molecular detection, visual observation following dissection, or using cardboard shelters to capture overwintering parasitized psylla. Future research will determine the relationship between adult Trechnites trap capture, psylla age distribution, and parasitism levels in the field so growers can anticipate the level of control provided by Trechnites in a given orchard. 08 Non-target effects of erythritol on the predatory mite Galendromus occidentalis. The artificial sweetener erythritol shows promise for controlling pear psylla. Pear psylla are currently the most critical pest of pears, but spider mites are ranked by growers as their second most important arthropod pest. Spider mite outbreaks occur when their natural enemies are killed by broad-spectrum pesticides used to control other pests, including pear psylla. To determine if erythritol can be integrated into pear pest management without causing spider mite outbreaks, researchers at the USDA in Wapato, Washington, examined the non-target effects of erythritol on the key predatory mite, Galendromus occidentalis in laboratory assays. Tests on this mite via multiple routes of exposure determined that erythritol is somewhat harmful to Galendromus occidentalis, but substantially less so than other psylla control products currently being used. Incorporation of erythritol into psylla management may allow growers to reduce the use of pesticides that are harmful to humans and beneficial organisms. 09 Determination of the thermal limits of apple maggot pupae. Apple maggot is a serious pest of apples in North America and is considered a pest of quarantine concern to most countries importing apples from the United States. Information on the survival and longevity of apple maggot under various rearing temperatures and day-lengths is needed to help predict the risk of apple maggot introductions in export countries. Researchers at the USDA in Wapato, Washington, investigated the potential impact of chill duration and exposure to tropical or subtropical climates and day-lengths on pupal diapause and subsequent adult emergence. They found that survival of apple maggot pupae was greatest when pupae were reared at 26-degrees C regardless of day- length, and that flies required more time to emerge when reared at lower temperatures and temperate day-lengths. These results will improve models to predict the probability of apple maggot to occupy environments different from those in North America. 10 Efficacies of cyantraniliprole, spinetoram, and Chromobacterium subtsugae biopesticide against Rhagoletis indifferens. Efficacies of cyantraniliprole, spinetoram, and Chromobacterium subtsugae biopesticide against western cherry fruit fly. Western cherry fruit fly is a quarantine pest of cherries in western North America. Diamides are a relatively new class of insecticides that appear effective in controlling fruit flies and could be useful in rotation with other insecticide chemistries to offset potential insecticide resistance. Personnel at the USDA laboratory in Wapato, Washington, compared efficacies of the diamide cyantraniliprole with that of the standard spinetoram and the biopesticide Chromobacterium subtsugae extract, either alone or mixed in bait against the fly. It was found that cyantraniliprole in bait caused as much or greater fly mortality and reduced oviposition more than spinetoram in bait. Chromobacterium subtsugae extract in bait usually did not cause mortality higher than controls. Results indicate that cyantranilirpole in bait could be useful as an insecticide for controlling western cherry fruit fly. 11 Distinct adult eclosion traits identified for sibling apple maggot fly and snowberry fly species. The apple maggot fly and snowberry fly are genetically closely related flies that attack apple and snowberry fruit, respectively. In part because of their use of different host plants, their responses to various environmental factors may have diverged. Personnel at the USDA laboratory in Wapato, Washington, Washington State University in Vancouver, Washington, and the University of Notre Dame, Indiana, compared the timing of adult fly emergence after their pupae were chilled or not. After chilling, emergence distributions of apple maggot flies were more dispersed than of snowberry flies. When pupae were not chilled, many more apple maggot than snowberry flies emerged. Results can benefit researchers who study evolutionary biology as well as Washington State Department of Agriculture and county pest control pest boards (regulatory agencies) that track emergence times and activity periods of apple maggot flies for management as well as activity periods of snowberry maggot flies, which can be confused with apple maggot flies.
Impacts
(N/A)
Publications
- Horwood, M., Milnes, J., Cooper, W.R. 2019. Brown marmorated stink bug, Halyomorpha halys (Hemiptera: Pentatomidae) (Stål, 1855), detections in Western Sydney, New South Wales, Australia. Austral Entomology. 58(4):857- 865.
- Elmquist, D.C., Landolt, P.J., Cooper, W.R., Reed, H., Foutz, J., Clepper, T., Kacprzyk, B., Teig, D., Zack, R.S. 2020. Polistes venom compound N-3- methylbutyl acetamide is a sex pheromone of Polistes metricus Say and attracts males of several Polistes (Fuscopolistes) species. Journal of Economic Entomology. 113(12):10-73-1079.
- Schmidt-Jeffris, R.A., Cutulle, M. 2019. Non-target impacts of herbicides on Tetranychus urticae and its predator, Phytoseiulus persimilis: implications for biological control. Pest Management Science. 75(12):3226- 3234.
- Wakie, T., Yee, W.L., Neven, L.G., Kumar, S. 2019. Modeling the abundance of two Rhagoletis fly (Diptera: Tephritidae) pests in Washington State, U. S.A.. PLoS One. 14(6).
- Yee, W.L., Forbes, A.A., Feder, J.L. 2020. Eclosion and adult longevity traits of Rhagoletis tabellaria (Diptera: Tephritidae) and Utetes tabellariae (Hymenoptera: Braconidae) in the laboratory. The Canadian Entomologist. 152(2):145-158.
- Doellman, M.M., Hood, G.R., Gersfeld, J., Driscoe, A., Xu, C., Sheehy, R., Holmes, N., Yee, W.L., Feder, J. 2020. Identifying diagnostic genetic markers for a cryptic invasive agricultural pest: a test case using the apple maggot fly, Rhagoletis pomonella (Diptera: Tephritidae). Annals of the Entomological Society of America. 113(4):246-256.
- Yee, W.L., Goughnour, R.B. 2019. Assessments of Rhagoletis pomonella (Diptera: Tephritidae) infestation of temperate, tropical, and subtropical fruit in the field and laboratory in Washington State, U.S. Journal of British Columbia Entomological Society. 116(3):40-58.
- Yee, W.L. 2020. Evaluation of Cyantraniliprole, Spinetoram, and Chromobacterium subtsugae extract in bait for killing and reducing oviposition of Rhagoletis indifferens (Diptera: Tephritidae). Journal of Economic Entomology. 113(3):1256-1362.
- Yee, W.L. 2020. Laboratory evaluation of CX-10282 containing Beauveria bassiana (Hypocreales: Clavicipitaceae) strain GHA against adult Rhagoletis indifferens (Diptera: Tephritidae). Phytoparasitica. 48(2):231- 245.
- Bergeron, P., Schmidt-Jeffris, R.A. 2020. Not all predators are equal: miticide non-target effects and differential selectivity. Pest Management Science. 76(6):2170-2179.
- Neven, L.G., Wakie, T., Yee, W.L. 2020. Low temperature duration and adult rearing regimes affect eclosion of Rhagoletis indifferens (Tephritidae: Diptera). Environmental Entomology. 49(3):660-666.
- Wakie, T., Neven, L.G., Yee, W.L., Lu, Z. 2019. The establishment risk of Lycorma delicatula (Hemiptera: Fulgoridae) in the United States and globally. Journal of Economic Entomology. 113(1):306-314.
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Progress 10/01/18 to 09/30/19
Outputs
Progress Report Objectives (from AD-416): This research will provide basic and applied information for the development and transfer of sustainable and environmentally acceptable methods and technologies for management of insect pests of temperate tree fruit crops. The objectives are: Objective 1: Develop new knowledge of the behavior, physiology, ecology, and biochemistry of insect pests and their natural enemies to suggest novel approaches to pest management and improve the use of existing methods, with focus on pest-host plant interactions of pear psylla and brown marmorated stink bug, pest-microbe interactions of codling moth and spotted wing drosophila, ecological and physiological criteria that limit pest distribution and abundance, and the functionality of codling moth receptors. Subobjective 1A. Determine and characterize interactions between pear trees and pear psylla and between the brown marmorated stink bug (BMSB) and preferred host plants. Subobjective 1B. Determine if volatiles emanating from microbial species found in the honeydew of aphids, mealybugs and psyllids are attractive to natural enemies. Subobjective 1C. Determine factors affecting pupal mortality and adult emergence of western cherry fruit fly (WCFF) in the field. Sub-objective 1D. Determine the upper and lower thermal limits for metabolism of different life stages of codling moth (CM), apple maggot (AM), and WCFF. Subobjective 1E. Develop a CRISPR/Cas9 gene knock out system to determine functions of proteins key to CM reproduction and development. Subobjective 1F: Determine undescribed cryptic species and undocumented range expansions of the community of minute pirate bugs in orchards and other habitats. Objective 2: Develop alternatives to fumigation to meet quarantine restrictions for pest insects in exported fruits, with focus on developing codling moth detector technology and ecological niche modeling to determine limits to the establishment and spread of quarantined insect pests. Subobjective 2A: Identify biochemical markers for apple fruit infested with CM larvae, in support of effort to develop detector technology. Subobjective 2B: Improve ecological niche models for the potential of tree fruit pests of quarantine concerns to establish and spread in potential new export markets. Objective 3: Develop and improve methods to reduce pesticide use and develop alternatives to pesticides, with focus on identifying and applying semiochemicals for pest management, and improved efficacy of natural enemies through application of foods and feeding attractants, and improvement of pear psylla control through induced or systemic acquired resistance in pear to psylla. Subobjective 3A. Develop an attract-and-kill approach for management of codling moth and leafrollers. Subobjective 3B. Improve efficacy of natural enemies through application of foods and feeding attractants. Subobjective 3C. Determine field temperature influences on the efficacy of the insecticide spinosad and Delegate for management of WCFF. Subobjective 3D. Improve pear psylla control through induced or systemic acquired resistance. Subobjective 3E. Evaluate the use of microbial-based feeding attractants for management of codling moth. Approach (from AD-416): 1A. Plant resistance to pear psylla will be characterized using greenhouse and biochemical assays and electrical penetration graphs. Host preferences by brown marmorated stink bug will be assessed by determining patterns of host plant use in non-crop landscapes. Stink bug attraction to host odor will be tested using a laboratory olfactometer. 1B. To develop methods of recruiting natural enemies to orchards, microbes present in aphid and pear psylla honeydew will be identified, and odors emanating from honeydew-associated microbes will be tested for attractiveness to natural enemies. 1C. Western cherry fruit fly adult emergence will be compared from soils with varying moisture and cover to determine whether fruit fly infestations in orchards can emanate from trees located in unmanaged habitats with dry soil surfaces. 1D. Data from differential scanning calorimetry and laboratory assays will provide estimates of metabolic thermal limits for codling moth, apple maggot, and western cherry fruit fly to determine the likelihood for these pests to establish and spread in new geographies. 1E. A CRISPR/Cas9 gene knock out system will be used to determine the function of proteins key to codling moth reproduction and development in support of work to develop species-specific behavioral and physiological modifying analogs for use in pest management. 1F. To improve conservation biological control in orchards, undescribed cryptic species and undocumented range expansions of minute pirate bugs in orchards and other habitats will be described based on morphometric analyses and molecular genetics. 2A. In support of efforts to develop technology to detect codling moth infestations in stored fruit, biochemical markers for infested apples will be identified using GC-MS, and laboratory studies will be used to determine how long marker chemicals are emitted from infested fruit. 2B. Experiments conducted in environmental chambers will be used to determine the effects of tropical and sub-tropical climates and photoperiods on the growth and development of codling moth, western cherry fruit fly, and apple maggot. Data will be used to improve ecological niche models for tree fruit pests of quarantine concerns to estimate the risk for these pests to establish and spread in export markets. 3A. New attractant blends will be developed as an attract-and-kill or mass trapping approach for management of codling moth and leafrollers. 3B. Plant-based attractive lures and food provisioning will be tested as attract-and-retain method of improving biological control in orchards. 3C. Effects of temperature on the efficacy of the insecticides Spinosad and Delegate for management of western cherry fruit fly will be determined using laboratory assays. 3D. Greenhouse assays and field studies will be used to test whether elicitors of host plant defenses can be used for the control of pear psylla. 3E. Laboratory studies will be performed to determine whether the addition of different yeast species with cane sugar stimulate codling moth feeding and increase the efficacy of ingested microbial or chemical insecticides against codling moth. Under Objective 1, progress was made on improving knowledge of the behavior and ecology of winterform pear psylla. Many winterforms leave pear to overwinter on shelter plants and then return to pear in the spring. In fiscal year FY19, high-throughput sequencing of plant deoxyribonucleic acid (DNA) present in pear psylla guts was used to infer the landscape-level movements of winterform pear psylla. Work was also initiated using ribonucleic acid (RNA) sequencing to identify the genetic mechanisms for changes in behaviors among summerform, diapausing winterform, and post-diapause winterform pear psylla. This work is providing a better understanding of the biology, behavior, and landscape ecology of the winterform pear psylla, which will allow us to develop or improve management tactics that target this portion of the population. Progress was made to determine factors that affect pupal mortality and adult emergence of western cherry fruit fly in the field. Immature stages of the fly overwinter as pupae in soil. The first year of the experiment determined that some soils are more conducive to pupal survival and adult fly emergence than others, but that soil moisture is needed for all soils to maximize survival. The second year of experimentation was initiated in FY19 and early-season results are now being tabulated to verify results from the first year. The upper and lower thermal limits of codling moth, apple maggot and western cherry fruit fly were determined using differential scanning calorimetry and were compared to previously published phenology models for these species. The differential scanning calorimetry values agreed with the phenology models and showed that differential scanning calorimetry can be used to quickly identify thermal limits for a species, making identification of limits for newly invasive species quicker and easier to obtain. This knowledge of thermal limits can aid in determining the potential for invasive species to establish and spread in new environments. Research continued from FY18 to characterize the role of putative odorant receptor genes in locating host plants and egg-laying sites. In addition, 40 neuropeptide/peptide hormone transcripts were identified using transcriptomes of the female abdomen tips, and research was initiated to characterize the roles of these genes. Taxonomic examination was performed on minute pirate bugs collected from several poorly studied geographic regions, including rural areas in Montana and Oregon, agricultural regions in central Washington State, and desert regions in southern California. These collections allowed advances to be made in determining the species diversity of minute pirate bugs in North America and helped clarify host plant associations of certain poorly studied species of these insects. These advances will lead to a new and updated identification key for the North American fauna of this important group of predatory insects. Subordinate projects related to Objective 1 include studies on Trechnites insidiosus, a parasitoid of pear psylla, and on predatory mites that attack pest spider mites. Work on Trechnites was initiated to compare trapping methods to monitor adult Trechnites populations and to correlate Trechnites population estimates with rates of parasitism of pear psylla. A Trechnites colony has also been created to determine pesticide non-target effects on this natural enemy; knowledge gained from this project will allow growers to make pesticide choices that minimally impact their Trechnites populations. Colonies of two species of predatory mites were established to support future work on pesticide non-target effects testing. Progress has also been made in assessing how gut contents of several predatory mite species changes throughout the season to better determine the role these organisms play in controlling pests in orchards. Ecological niche models help identify environments where a species may establish and spread. This is important not only for newly invasive species, but for endemic species whose range may expand in response to climate change. Ecological niche models are only as accurate as the data used to train the program (machine learning). The addition of critical physiological parameters, such as upper and lower thermal limits, as well as the species distribution across different landscapes, can increase the accuracy and predictability of these models. In support of Objective 2, largescale landscape heterogeneity study for four important tree fruit pests ⿿ codling moth, oriental fruit moth, apple maggot, and western cherry fruit fly ⿿ was conducted in Washington State and underscored differences in habitat and landscape utilization among the four species. The landscape heterogeneity was also used to project the potential spread of these species in response to climate change. The strength of these models is that they can point out critical locations to concentrate pest control measures to stem the expansion of the distribution of these pests. Laboratory and field experiments were initiated in support of Objective 3 to determine whether the artificial sweetener, erythritol, is lethal to pear psylla and other key pests of pear when applied to pear leaves. Progress was made on determining temperature influences on the efficacy of the insecticides, spinosad and Delegate, for management of western cherry fruit fly. This was determined under laboratory conditions, as determining the influence of temperatures on insecticide effects in the field proved too difficult because larval infestations in cherries were non-existent, even in control trees in some years. Laboratory tests were completed and showed that under higher temperatures, flies were more active and killed more quickly by both materials applied on surfaces than at lower temperatures. However, more oviposition occurred at higher than lower temperatures. In subordinate projects related to Objective 3, substantial progress was made toward developing attractive lures for monitoring and controlling paper wasps. Experiments were completed showing that the invasive European paper wasp is attracted to peony plants, and studies are underway to identify which peony compounds the wasps are attracted. A compound from the female sting apparatus of paper wasps was also found to be highly attractive to male wasps, and field experiments demonstrated that traps baited with the compound capture large numbers of wasps. Accomplishments 01 Molecular gut content analysis of pear psylla. Pear psylla, the key insect pest of pears, occurs as two behavioral forms referred to as the summerform and winterform. The winter form of pear psylla is known to leave orchards in large numbers and overwinter on non-pear plants before recolonizing orchards in spring. ARS researchers in Wapato, Washington, in collaboration with scientists from Washington State University and Oregon State University, developed a method for gut content analysis of pear psylla and demonstrated that this method can be used to infer diets and landscape-level movements of psylla. Scientists then used this new tool to discover that the so-called non- dispersing summer stage of pear psylla, much like the winter behavioral form, is actually quite dispersive, and moves into habitats surrounding orchards in summer from which they then colonize new orchards. This unexpected finding must be acknowledged in predicting summer outbreaks of psylla in orchards and in evaluating spread of insecticide-resistant genotypes. Methods used in developing this new tool were published in a peer-reviewed journal, and that article was then featured in Entomology Today, a web-based publication of the Entomological Society of America which provides popularized or layperson accounts of new and interesting discoveries in entomology. 02 Three-dimensional versus rectangular sticky yellow traps for western cherry fruit fly. Western cherry fruit fly is a major quarantine pest of cherries in western North America that can be monitored using sticky yellow traps, but it is unclear which traps are best at detecting the fly. Personnel at ARS laboratory in Wapato, Washington, determined the effectiveness of three-dimensional versus rectangle yellow traps for catching the fly. It was found that a cross trap made of thin yellow plastic was more effective than a similar cross trap made of a thicker yellow plastic and yellow rectangles. Further work showed that its effectiveness was due to its large surface area and possibly its shade of yellow. Results are important in that the new cross trap could be an effective option or addition to rectangles for monitoring the fly. 03 New attractive lure to monitor and control paper wasps. Several species of Polistes paper wasps are significant pests when they swarm and aggregate on man-made structures in the southeastern U.S. Paper wasps use chemicals to communicate during these swarms, and identification of these chemicals may provide attractants that are useful for wasp control. ARS researchers in Wapato, Washington, Washington State University, and Department of Defense, found that paper wasps were attracted to a compound, N-3-methybutyl acetamide (MBA), emitted from the female wasp venom, and demonstrated that traps baited with MBA capture large numbers of wasps. This study shows that traps baited with MBA will be an effective tool to monitor and control paper wasps. 04 Potential establishment of spotted lanternfly in the world. Native to Asia, the spotted lanternfly is an emerging pest of many commercially important plants in Korea, Japan, and the U.S. Determining its potential distribution is important for developing proactive measures to protect commercially important commodities. ARS researchers in Wapato, Washington, used ecological niche modeling to predict highly suitable areas for spotted lanternfly in Asia, Oceania, South America, North America, Africa, and Europe, but also predicted that tropical habitats are not suitable for its establishment, contrary to published information. Within the U.S., the ecological niche modeling predicted that spotted lanternfly can establish in Pennsylvania, New Jersey, Virginia, West Virginia, Delaware, New York, Massachusetts, Rhode Island, New Hampshire, Connecticut, Maryland, Virginia, North Carolina, Kentucky, West Virginia, Ohio, Indiana, Michigan, Illinois, Iowa, Missouri, Kansas, California, Washington, and Oregon. If introduced, the spotted lanternfly is likely to establish in fruit-growing regions of the Pacific Northwest. Results of this study can be used by regulatory agencies to guide spotted lanternfly surveys and prioritize management interventions for this pest. 05 Eclosion and adult longevity traits of Rhagoletis tabellaria and Utetes tabellariae. Rhagoletis (R.) tabellaria is a fruit fly that attacks dogwood and has been implicated as a pest of some commercial fruit, but little is known of its biology. ARS researchers in Wapato, Washington, in collaboration with the University of Iowa, and the University of Notre Dame, determined the effects of chilling on emergence and longevity of R. tabellaria and its major parasitic wasp. When chilled, flies emerged earlier than wasps in accordance with when fly stages are available for attack. Although the parasite did not require chilling to complete development, R. tabellaria failed to emerge when not chilled, suggesting different physiological responses to cold by host and parasite. Flies survived longer than wasps in accordance with the short period when susceptible fly stages are available for attack. Results are important in that they expand our knowledge of Rhagoletis flies and their coevolution with their parasites. 06 Temperate and tropical/subtropical fruit use by apple maggot. The apple maggot fly is a threat to domestic and foreign fruit markets. This threat can be reduced through knowledge of host plant use by the fly. The apple maggot fly is a threat to domestic and foreign fruit markets. This threat can be reduced through knowledge of host plant use by the fly. ARS researchers in Wapato, Washington, in collaboration with Washington State University, determined the use of unmanaged (non- commercial) apple and hawthorn trees by the fly in Washington. The researchers surveyed various fruit for use by the fly and tested whether tropical and subtropical fruits are suitable for attack by the fly. They learned that several plants were recorded as new hosts and discovered that hawthorns were used more than unmanaged apple trees and most subtropical and tropical fruit were not suitable for the fly. Findings are important in that they could be useful for developing policies to protect both U.S. and subtropical fruit markets. These data have been added to the USDA-APHIS handbook on Fruit Flies. 07 Modeling abundance of two fruit flies in Washington State. Apple maggot and western cherry fruit fly are the two key quarantine pests of apples and cherries in Washington State. These flies are a threat to the tree fruit industry due to quarantine-related market restrictions. There is little quantitative information on where they are found, and what environmental factors affect the abundance of these flies. ARS researchers in Wapato, Washington, conducted a landscape heterogeneity study in which they determined that apple maggot is abundant in western Washington and less abundant in central and eastern Washington. In contrast, western cherry fruit fly is abundant in central and eastern Washington and less abundant in western Washington. Establishment of Low Pest Prevalence or Pest Free Areas are recommended in areas with zero or very low apple maggot abundance to allow the movement of apples without cold treatments. These data have been published in a peer- reviewed scientific journal and shared with the tree fruit industry, Washington Department of Agriculture, and USDA-Animal and Plant Health Inspection Service for assistance in negotiating export workplans and agreements for tree fruits from the Pacific Northwest. 08 Environmental effects on western cherry fruit fly diapause. There is a zero tolerance for the presence of western cherry fruit fly in commercially produced sweet cherries, and this pest has often been cited as a quarantine concern by current and perspective importers. ARS researchers in Wapato, Washington, assessed whether chilling duration, rearing temperature, humidity, and photoperiod influenced diapause completion and emergence of western cherry fruit fly. They determined that a chilling period of 15 weeks or greater is necessary to begin synchronous emergence of western cherry fruit fly, and that rearing temperature affected the timing of fly emergence. Photoperiod and humidity did not affect timing of emergence. These data can be used to determine whether western cherry fruit fly poses a threat to other countries importing sweet cherries from the Pacific Northwest.
Impacts
(N/A)
Publications
- Lane, J., Kumar, S., Yee, W.L. 2018. Modeling the climatic suitability for Fopius arisanus (Hymenoptera: Braconidae) and its host fly Bactrocera dorsalis (Diptera: Tephritidae). Journal of Economic Entomology. 154(1):65- 78.
- Tadeo, E., Muniz, E., Rull, J., Yee, W.L., Aluja, M., Lasa, R. 2017. Development of a low-cost and effective trapping device for apple maggot fly (Diptera: Tephritidae) monitoring and control in Mexican commercial hawthorn groves. Journal of Economic Entomology. 100(4):1658-1667.
- Zhu, H., Kumar, S., Neven, L.G. 2017. Codling moth establishment in China: Stages of invasion and potential future distribution. Journal of Insect Science. 17(4):85.
- Yee, W.L. 2018. Efficacies of Rhagoletis cerasi traps and ammonium lures for Western Cherry Fruit Fly (Diptera: Tephritidae). Journal of Insect Science. 18(3):14.
- Yee, W.L. 2018. Spinosad versus Spinetoram effects on kill and oviposition of Rhagoletis indifferens (Diptera: Tephritidae) at differing fly ages and temperatures. Journal of Insect Science. 18(4):15.
- Yee, W.L., Chapman, P.S. 2018. Irrigation and grass cover effects on pupal survival rates in soil and adult emergence patterns of Rhagoletis indifferens (Diptera: Tephritidae). Environmental Entomology. 47(2):457- 466.
- Cooper, W.R., Horton, D.R., Wildung, M., Jensen, A., Thinakaran, J., Rendon, D., Nottingham, L., Beers, E., Wohleb, C., Hall, D.G., Stelinski, L. 2019. Host and non-host whistle stops by psyllids: Molecular gut content analysis by high-throughput sequencing reveals landscape-level movements by Psylloidea (Hemiptera). Environmental Entomology. 48(3):554- 566.
- Knight, A.L., Stewart, W.L., Basoalto, E. 2018. Importance of trap liner adhesive selection for male moth catch (Lepidoptera: Tortricidae) with bisexual attractants. Journal of Applied Entomology. 142(8):731-744.
- Knight, A.L., Light, D.M. 2018. Pear ester - from discovery to delivery for improved codling moth management. In: Beck, J., Rering, C.C., Duke, S. O., editors. Roles of Natural Products for Biorational Pesticides in Agriculture. Washington, D.C.: ACS Publications. p. 83-113.
- Judd, G., Knight, A.L. 2017. Trapping female Pandemis limitata (Lepidoptera: Tortricidae) moths with mixtures of acetic acid, benzenoid apple leaf volatiles, and sex pheromones. The Canadian Entomologist. 149(6) :813-822.
- Judd, G., Knight, A.L. 2017. Developing kairomone-based lures and traps targeting female Spilonota ocellana (Lepidoptera: Tortricidae) in apple orchards treated with sex pheromones. The Canadian Entomologist. 149(5):1- 15.
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Progress 10/01/17 to 09/30/18
Outputs
Progress Report Objectives (from AD-416): This research will provide basic and applied information for the development and transfer of sustainable and environmentally acceptable methods and technologies for management of insect pests of temperate tree fruit crops. The objectives are: Objective 1: Develop new knowledge of the behavior, physiology, ecology, and biochemistry of insect pests and their natural enemies to suggest novel approaches to pest management and improve the use of existing methods, with focus on pest-host plant interactions of pear psylla and brown marmorated stink bug, pest-microbe interactions of codling moth and spotted wing drosophila, ecological and physiological criteria that limit pest distribution and abundance, and the functionality of codling moth receptors. Subobjective 1A. Determine and characterize interactions between pear trees and pear psylla and between the brown marmorated stink bug (BMSB) and preferred host plants. Subobjective 1B. Determine if volatiles emanating from microbial species found in the honeydew of aphids, mealybugs and psyllids are attractive to natural enemies. Subobjective 1C. Determine factors affecting pupal mortality and adult emergence of western cherry fruit fly (WCFF) in the field. Sub-objective 1D. Determine the upper and lower thermal limits for metabolism of different life stages of codling moth (CM), apple maggot (AM), and WCFF. Subobjective 1E. Develop a CRISPR/Cas9 gene knock out system to determine functions of proteins key to CM reproduction and development. Subobjective 1F: Determine undescribed cryptic species and undocumented range expansions of the community of minute pirate bugs in orchards and other habitats. Objective 2: Develop alternatives to fumigation to meet quarantine restrictions for pest insects in exported fruits, with focus on developing codling moth detector technology and ecological niche modeling to determine limits to the establishment and spread of quarantined insect pests. Subobjective 2A: Identify biochemical markers for apple fruit infested with CM larvae, in support of effort to develop detector technology. Subobjective 2B: Improve ecological niche models for the potential of tree fruit pests of quarantine concerns to establish and spread in potential new export markets. Objective 3: Develop and improve methods to reduce pesticide use and develop alternatives to pesticides, with focus on identifying and applying semiochemicals for pest management, and improved efficacy of natural enemies through application of foods and feeding attractants, and improvement of pear psylla control through induced or systemic acquired resistance in pear to psylla. Subobjective 3A. Develop an attract-and-kill approach for management of codling moth and leafrollers. Subobjective 3B. Improve efficacy of natural enemies through application of foods and feeding attractants. Subobjective 3C. Determine field temperature influences on the efficacy of the insecticide spinosad and Delegate for management of WCFF. Subobjective 3D. Improve pear psylla control through induced or systemic acquired resistance. Subobjective 3E. Evaluate the use of microbial-based feeding attractants for management of codling moth. Approach (from AD-416): 1A. Plant resistance to pear psylla will be characterized using greenhouse and biochemical assays and electrical penetration graphs. Host preferences by brown marmorated stink bug will be assessed by determining patterns of host plant use in non-crop landscapes. Stink bug attraction to host odor will be tested using a laboratory olfactometer. 1B. To develop methods of recruiting natural enemies to orchards, microbes present in aphid and pear psylla honeydew will be identified, and odors emanating from honeydew-associated microbes will be tested for attractiveness to natural enemies. 1C. Western cherry fruit fly adult emergence will be compared from soils with varying moisture and cover to determine whether fruit fly infestations in orchards can emanate from trees located in unmanaged habitats with dry soil surfaces. 1D. Data from differential scanning calorimetry and laboratory assays will provide estimates of metabolic thermal limits for codling moth, apple maggot, and western cherry fruit fly to determine the liklihood for these pests to establish and spread in new geographies. 1E. A CRISPR/Cas9 gene knock out system will be used to determine the function of proteins key to codling moth reproduction and development in support of work to develop species-specific behavioral and physiological modifying analogs for use in pest management. 1F. To improve conservation biological control in orchards, undescribed cryptic species and undocumented range expansions of minute pirate bugs in orchards and other habitats will be described based on morphometric analyses and molecular genetics. 2A. In support of efforts to develop technology to detect codling moth infestations in stored fruit, biochemical markers for infested apples will be identified using GC-MS, and laboratory studies will be used to determine how long marker chemicals are emitted from infested fruit. 2B. Experiments conducted in environmental chambers will be used to determine the effects of tropical and sub-tropical climates and photoperiods on the growth and development of codling moth, western cherry fruit fly, and apple maggot. Data will be used to improve ecological niche models for tree fruit pests of quarantine concerns to estimate the risk for these pests to establish and spread in export markets. 3A. New attractant blends will be developed as an attract-and-kill or mass trapping approach for management of codling moth and leafrollers. 3B. Plant-based attractive lures and food provisioning will be tested as attract-and-retain method of improving biological control in orchards. 3C. Effects of temperature on the efficacy of the insecticides Spinosad and Delegate for management of western cherry fruit fly will be determined using laboratory assays. 3D. Greenhouse assays and field studies will be used to test whether elicitors of host plant defenses can be used for the control of pear psylla. 3E. Laboratory studies will be performed to determine whether the addition of different yeast species with cane sugar stimulate codling moth feeding and increase the efficacy of ingested microbial or chemical insecticides against codling moth. This progress report covers year three of the continuing project to develop and improve sustainable and biorational management of insect pests of temperate tree fruits. Key pests of concern include codling moth, pear psylla, spotted wing drosophila, apple maggot, and western cherry fruit fly. Substantial progress was made on all three project objectives during fiscal year 2018. Objective 1: Experiments have been initiated to identify mechanisms of plant resistance to pear psylla in several varieties or landraces of pear. Methods include fluorescence in situ hybridization and electrical penetration graphs to compare stylet-pathways and feeding behaviors on resistant and susceptible pear. Identification of resistance mechanisms will help breeders incorporate resistance traits in marketable varieties and will enable researchers to develop management programs which reduce the risk for pear psylla populations to develop virulence to plant resistance. Experiments are also underway to study the landscape-level migration patterns of pear psylla by optimizing a method for molecular gut content analysis to identify plant DNA in psylla for use under field conditions. This method is now being used to determine the dietary histories of field-collected psylla as they recolonize pear orchards in early spring. Identification of shelter plant sources of overwintered psylla that colonize pear will help growers target this bottlenecked stage of the population. Biology of western cherry fruit fly: Western cherry fruit fly is abundant in unmanaged cherries in irrigated areas in the dry interior of the Pacific Northwest (PNW) of the U.S. Irrigation may allow pupae to survive in soil during hot summers when risk of heat stress and desiccation is greatest. The effects of three soil types either dry or moist on emergence times and survival of cherry fruit fly were tested in the field. Larvae were added to pots with different soils and moistures embedded in the ground in July and August 2017. Emergence of flies in 2018 was determined by placing a cage with a sticky yellow card above each pot. Data are currently being collected and will be completed by August. Biology of apple maggot: Studies have been initiated to characterize the olfactory system of apple maggot and to identify and characterize target proteins that may lead to novel methods to keep commercial apples free of infestations. Odorant receptors, key proteins that mediate insect behaviors in response to apple volatiles, have been identified in transcriptomes generated from antennae of apple maggot males and females. With this knowledge, characterizations of specific odorant receptors are underway with the goal of identifying those that play key roles in apple maggot finding its host plant. Biology of codling moth: Clustered regularly interspaced short palindromic repeats/CRISPR-associated 9 (CRISPR/Cas9) genome editing has been developed and successfully used to inactivate codling moth genes. This technique enables the rapid identification of novel protein targets that may be useful for codling moth control. Genes encoding odorant receptors, proteins that regulate female codling moth behaviors used to locate host plants and identify egg-laying sites, are potentially valuable targets for insect control in the orchard. In transcriptomes generated and analyzed in the past year, 15 odorant receptors that potentially respond to apple volatile compounds have been identified in both antennae (used to locate host plants) and abdomen tips (used to identify egg-laying sites). Using the transcriptome information, genes that encode the 15 odorant receptors have been identified and transcripts for 12 of these receptors have been characterized. From these characterizations, the components for CRISPR/Cas9 genome editing system have been generated. In the upcoming year, experiments will be performed to determine which odorant receptor targets have the greatest potential for use to control codling moth in the orchard. Biology of minute pirate bugs: Understanding the role of natural enemies in orchards is made more complex with our realization that the natural enemy community in orchards and neighboring habitats includes species not previously known to occur in the PNW. One important group of predators includes the minute pirate bugs, which are generalist predators of mites, psyllids, aphids, eggs and small larvae of caterpillars, and other soft- bodied arthropods. Ongoing collecting of minute pirate bugs from the western U.S. and Canada, combined with examination of specimens obtained through loans from university museums, has led to the discovery of several unnamed species. Identifying these cryptic species was found to require a combination of behavioral assays (mating trials), plant records, morphological and anatomical examination, and analysis of DNA-sequences. At least 2 of these unnamed species appear to be substantially limited in the number of plant species with which they associate, which is behavior quite different from that of our more common and named species. Collecting efforts in the western U.S. are continuing. A key to species of North America is being developed that relies on external traits of specimens, host plant records, and structure of the male and female reproductive organs. This key will allow researchers to identify to species minute pirate bugs from western North America, including currently unnamed species. Objective 2: Significant progress was made on determining the upper and lower thermal limits of codling moth using differential scanning calorimetry. The immature stages completed are the egg, 4th and 5th instar, and the pupae. These thermal limits were used in ecological niche modeling papers for the world and China. The world maps were shared with both the industry and the United States Department of Agriculture-Animal and Plant Health Inspection Service (USDA-APHIS) to address concerns of apple importing countries in relation to the invasive potential of codling moth in their country. The model for China was developed to determine the stages of codling moth invasion, spread, and establishment in China to help develop control strategies to stem the spread of this destructive pest. Upon completion of the dataset, the values for the other immature stages will be used to modify, if needed, the current ecological niche maps. Objective 3: Spinosad (Entrust) and spinetoram (Delegate) effects on kill and oviposition of western cherry fruit fly were determined by exposing 3-4, 7-10, or 14-18 day old flies to dry spinosad and spinetoram and untreated cherries or to insecticide-treated cherries at 15.6 degrees Centigrade (�C), 22.5�C, and 29.4�C to improve attract-and-kill approaches for western cherry fruit fly management. It was found that kill was not affected by fly age. Spinetoram killed more female flies by day 1 than spinosad at all temperatures. In both treatments, kill was lower at 15.6�C than 22.5�C and 29.4�C, although a difference between 22. 5 and 29.4�C was detected more often in spinosad treatments. Both insecticides killed 3-4 day old flies quickly enough to prevent oviposition (the process of laying eggs), but neither prevented oviposition by 7-10 and 14-18 day old flies. Oviposition by flies exposed to spinosad and spinetoram did not differ at any temperature. Results indicate spinetoram is more toxic to flies than spinosad, but that higher toxicity is not needed to prevent oviposition by younger flies. Spineotoram residues are not sufficient to kill older flies quickly enough to reduce oviposition more than spinosad. Studies were conducted to address several components needed to develop a successful, efficacious attract and kill approach for codling moth and leafrollers. Flight tunnel studies have compared the effectiveness of different trap liners with captured females to lure additional males to the trap. Studies were conducted to develop a liquid method to catch moths in bucket traps that combines the use of organic oil, vinegar, and propylene glycol. The interaction of several aromatic volatiles with the sex pheromones of leafrollers were evaluated. Mass trapping studies are currently in place in commercial orchards. Further field comparisons of volatile blends for codling moth and leafrollers are being investigated. Studies are also being conducted to characterize the volatiles released by various microbes that are both present in various host plants and in shoots damaged by aphids and leafroller larvae. The microbiome will be characterized, prominent species will be cultured and identified, and volatile emissions will be collected to develop new attractants for leafrollers. Accomplishments 01 Identification of odorant receptors expressed in the abdomen tips of codling moth females. Odorant receptors are the key proteins involved in the insect sense of smell and study of these proteins has mainly focused on those expressed in antennae (the insect equivalent of our nose) which overlooks the other important odorant receptors. Scientists at the USDA-ARS Temperate Tree Fruit and Vegetable Research Unit in Wapato, Washington, and at the Swedish University of Agricultural Sciences, Alnarp, Sweden have used genomic technology to identify 39 odorant receptors expressed in female abdomen tips. Almost half of the odorant receptors identified in the abdomen tip are highly related to receptors in other insects that have been shown to respond to plant- derived semiochemicals, suggesting a potential role in oviposition site identification. The results produced in this study provide insights in how codling moth females locate host plants and egg-laying sites and may lead to more effective biorational control strategies against this insect pest. 02 Identified temperatures in waste piles deadly to apple maggot fly pupae. The apple maggot fly is a major quarantine pest of commercial apple in the U.S. Movement of plant waste containing apple maggot fly pupae to apple-growing areas for composting threatens the apple industry in Washington. ARS scientists in Wapato, Washington, determined whether heat in waste piles can kill pupae by placing pupae in small bags at different depths in ground plant waste piles covered with tarp insulation. Except near the bottom of piles during cold weather, all pupae exposed to heat in piles were killed. Results are important in that they show insulating ground plant waste piles is effective for killing apple maggot pupae. During cold periods, bottoms of piles may also need to be insulated to kill pupae near the ground, making the process more effective. 03 Efficacies of European cherry fruit fly traps. Western cherry fruit fly is a quarantine pest of cherries in western North America that is best detected using Yellow Sticky Strip (YSS) rectangle traps. Recently, the European cherry fruit fly invaded eastern North America, prompting surveys for it in the West. Sticky crossed-panel yellow Rebell and cylindrical-type yellow PALz traps were developed for this fly, raising the question of efficacies of these traps versus the YSS against western cherry fruit fly. ARS scientists in Wapato, Washington, determined the efficacies of the YSS versus Rebell and PALz traps baited with ammonia against western cherry fruit fly. The Rebell and YSS traps caught similar numbers of flies and more than the PALz trap. This result is important because it shows that the Rebell trap could be used to monitor western cherry fruit fly and suggests that the PALz trap is selectively better than the Rebell trap for surveys of European cherry fruit fly, as fewer western cherry fruit flies would clutter traps. 04 Reducing the emergence and survival of western cherry fruit fly. Western cherry fruit fly is a threat to the commercial cherry industry in the western U.S. The fly�s ability to survive in dry climates affects its distribution and pest status, but it is unclear if its survival rates are increased by irrigation in different soils. ARS scientists in Wapato, Washington, determined the effects of adding water to bare and grass-covered soils on survival rates of fly pupae in central Washington. Results showed that fly pupae survived equally well in irrigated and unirrigated bare soils but suffered relatively high mortality in unirrigated grass-covered soils. Results are important because they show that unirrigated, grass-covered soils or mulch barriers in mid- and late-summer could reduce fly survival, thus suppressing fly abundance. 05 Risk of global establishment of the European cherry fruit fly (ECFF). The European cherry fruit fly or Rhagoletis cerasi, is a highly destructive pest of cherries in Europe and Asia. The pest was recently detected in Canada and the U.S. for the first time. Its further expansion could threaten the tree fruit industry in the U.S., including the major cherry growing regions of Michigan, Washington, Oregon, and California. ARS scientists in Wapato, Washington, used ecological niche models to determine the risk of ECFF global establishment focusing on the major cherry growing regions of the U.S. Results show that under a no-irrigation scenario, the pest would establish in the East and West Coasts of the U.S; however, under an irrigation scenario, its distribution would expand to the major cherry-growing regions in the interior of central and eastern Washington and in California. Our results stress the importance of surveying for European cherry fruit fly to prevent its spread and establishment, both globally and particularly, in the U.S. 06 Phytoplasma alters flight behavior of pear psylla. Pear psylla is a key pest of pear and one of the most serious insect pest of pears because of its ability to develop resistance to insecticides and to vector the pathogen that causes pear decline. In the pear growing regions of the Pacific Northwest, nearly thirty percent of pear psylla harbor the plant pathogen Phytoplasma pyri, but the effects of Phytoplasma on pear psylla biology are not known. ARS scientists in Wapato, Washington, in collaboration with researchers at Heritage University in Toppenish, Washington, found that pear psylla infected with Phytoplasma are less likely to disperse from pear trees. By showing that Phytoplasma alters pear psylla flight behavior, these results will help elucidate patterns in psylla dispersal and colonization of pear orchards.
Impacts
(N/A)
Publications
- Yee, W.L. 2017. Temperature and food availability effects on spinosad and malathion against Rhagoletis indifferens (Diptera: Tephritidae) in the laboratory. Phytoparasitica. 45(5):673-682.
- Elmquist, D.C., Landolt, P.J., Ream, L.J., Cha, D.H. 2017. Laboratory demonstrations of pheromone-mediated scent-marking, orientation, and mounting behavior in Polistes exclamans Vienick (Hymenoptera: Vespidae). Annals of the Entomological Society of America. 111(1):21-30.
- Neven, L.G., Kumar, S., Yee, W.L., Wakie, T. 2018. Current and Future Potential Risk of Establishment of Grapholita molesta (Lepidoptera: Tortricidae) in Washington State. Environmental Entomology. 47(2):448-456.
- Wakie, T., Yee, W.L., Neven, L.G. 2018. Assessing the risk of global establishment of Rhagoletis cerasi (Diptera: Tephritidae), with emphasis on the United States. Journal of Economic Entomology. 111(3):1275-1284.
- Jaffe, B., Landolt, P.J. 2018. Field validation of a three chemical controlled release dispenser to attract codling moth (Cydia pomonella) (Lepidoptera: Tortricidae). Journal of Economic Entomology. 111(3):1268- 1274.
- Tassin, M., Herrera, S., Knight, A.L., Barros-Prada, W., Contreras, E., Pertot, I. 2018. Volatiles of grape inoculated with microorganisms: Modulation of grapevine moth oviposition and field attraction. Microbial Ecology.
- Horton, D.R., Miliczky, E., Lewis, T.M., Cooper, W.R., Waters, T., Wohleb, C., Zack, R., Johnson, D., Jensen, A. 2018. New North American records for the Old World psyllid Heterotrioza chenopodii (Reuter) with biological observations (Hemiptera: Psylloidea: Triozidae). Proceedings of the Entomological Society of Washington. 120(1):134-152.
- Gundersen, D.E., Adrianos, S.L., Allen, M.L., Becnel, J.J., Chen, Y., Choi, M.Y., Estep, A., Evans, J.D., Garczynski, S.F., Geib, S.M., Ghosh, S.B., Handler, A.M., Hasegawa, D.K., Heerman, M.C., Hull, J.J., Hunter, W.B., Kaur, N., Li, J., Li, W., Ling, K., Nayduch, D., Oppert, B.S., Perera, O.P. , Perkin, L.C., Sanscrainte, N.D., Sim, S.B., Sparks, M., Temeyer, K.B., Vander Meer, R.K., Wintermantel, W.M., James, R.R., Hackett, K.J., Coates, B.S. 2017. Arthropod genomics research in the United States Department of Agriculture-Agricultural Research Service: Applications of RNA interference and CRISPR gene editing technologies in pest control. Trends in Entomology. 13:109-137.
- Yee, W.L., Goughnour, R.B., Feder, J.L., Linn, C.E., Cha, D.H. 2017. Comparative responses of Rhagoletis zephyria and R. pomonella (Diptera: Tephritidae) to commercial and experimental sticky traps and odors in Washington State. Environmental Entomology. 46(6):1351-1358.
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Progress 10/01/16 to 09/30/17
Outputs
Progress Report Objectives (from AD-416): This research will provide basic and applied information for the development and transfer of sustainable and environmentally acceptable methods and technologies for management of insect pests of temperate tree fruit crops. The objectives are: Objective 1: Develop new knowledge of the behavior, physiology, ecology, and biochemistry of insect pests and their natural enemies to suggest novel approaches to pest management and improve the use of existing methods, with focus on pest-host plant interactions of pear psylla and brown marmorated stink bug, pest-microbe interactions of codling moth and spotted wing drosophila, ecological and physiological criteria that limit pest distribution and abundance, and the functionality of codling moth receptors. Subobjective 1A. Determine and characterize interactions between pear trees and pear psylla and between the brown marmorated stink bug (BMSB) and preferred host plants. Subobjective 1B. Determine if volatiles emanating from microbial species found in the honeydew of aphids, mealybugs and psyllids are attractive to natural enemies. Subobjective 1C. Determine factors affecting pupal mortality and adult emergence of western cherry fruit fly (WCFF) in the field. Sub-objective 1D. Determine the upper and lower thermal limits for metabolism of different life stages of codling moth (CM), apple maggot (AM), and WCFF. Subobjective 1E. Develop a CRISPR/Cas9 gene knock out system to determine functions of proteins key to CM reproduction and development. Subobjective 1F: Determine undescribed cryptic species and undocumented range expansions of the community of minute pirate bugs in orchards and other habitats. Objective 2: Develop alternatives to fumigation to meet quarantine restrictions for pest insects in exported fruits, with focus on developing codling moth detector technology and ecological niche modeling to determine limits to the establishment and spread of quarantined insect pests. Subobjective 2A: Identify biochemical markers for apple fruit infested with CM larvae, in support of effort to develop detector technology. Subobjective 2B: Improve ecological niche models for the potential of tree fruit pests of quarantine concerns to establish and spread in potential new export markets. Objective 3: Develop and improve methods to reduce pesticide use and develop alternatives to pesticides, with focus on identifying and applying semiochemicals for pest management, and improved efficacy of natural enemies through application of foods and feeding attractants, and improvement of pear psylla control through induced or systemic acquired resistance in pear to psylla. Subobjective 3A. Develop an attract-and-kill approach for management of codling moth and leafrollers. Subobjective 3B. Improve efficacy of natural enemies through application of foods and feeding attractants. Subobjective 3C. Determine field temperature influences on the efficacy of the insecticide spinosad and Delegate for management of WCFF. Subobjective 3D. Improve pear psylla control through induced or systemic acquired resistance. Subobjective 3E. Evaluate the use of microbial-based feeding attractants for management of codling moth. Approach (from AD-416): 1A. Plant resistance to pear psylla will be characterized using greenhouse and biochemical assays and electrical penetration graphs. Host preferences by brown marmorated stink bug will be assessed by determining patterns of host plant use in non-crop landscapes. Stink bug attraction to host odor will be tested using a laboratory olfactometer. 1B. To develop methods of recruiting natural enemies to orchards, microbes present in aphid and pear psylla honeydew will be identified, and odors emanating from honeydew-associated microbes will be tested for attractiveness to natural enemies. 1C. Western cherry fruit fly adult emergence will be compared from soils with varying moisture and cover to determine whether fruit fly infestations in orchards can emanate from trees located in unmanaged habitats with dry soil surfaces. 1D. Data from differential scanning calorimetry and laboratory assays will provide estimates of metabolic thermal limits for codling moth, apple maggot, and western cherry fruit fly to determine the liklihood for these pests to establish and spread in new geographies. 1E. A CRISPR/Cas9 gene knock out system will be used to determine the function of proteins key to codling moth reproduction and development in support of work to develop species-specific behavioral and physiological modifying analogs for use in pest management. 1F. To improve conservation biological control in orchards, undescribed cryptic species and undocumented range expansions of minute pirate bugs in orchards and other habitats will be described based on morphometric analyses and molecular genetics. 2A. In support of efforts to develop technology to detect codling moth infestations in stored fruit, biochemical markers for infested apples will be identified using GC-MS, and laboratory studies will be used to determine how long marker chemicals are emitted from infested fruit. 2B. Experiments conducted in environmental chambers will be used to determine the effects of tropical and sub-tropical climates and photoperiods on the growth and development of codling moth, western cherry fruit fly, and apple maggot. Data will be used to improve ecological niche models for tree fruit pests of quarantine concerns to estimate the risk for these pests to establish and spread in export markets. 3A. New attractant blends will be developed as an attract-and-kill or mass trapping approach for management of codling moth and leafrollers. 3B. Plant-based attractive lures and food provisioning will be tested as attract-and-retain method of improving biological control in orchards. 3C. Effects of temperature on the efficacy of the insecticides Spinosad and Delegate for management of western cherry fruit fly will be determined using laboratory assays. 3D. Greenhouse assays and field studies will be used to test whether elicitors of host plant defenses can be used for the control of pear psylla. 3E. Laboratory studies will be performed to determine whether the addition of different yeast species with cane sugar stimulate codling moth feeding and increase the efficacy of ingested microbial or chemical insecticides against codling moth. This progress report covers year two for the continuing project to develop and improve sustainable and biorational management and quarantine security of insect pests of temperate tree fruits. Key pests of concern include codling moth, pear psylla, spotted wing drosophila, apple maggot, and western cherry fruit fly. Substantial progress was made on all three objectives during this fiscal year. Brown marmorated stink bug (BMSB) is a recent introduction to the Pacific Northwest. There is little experience with managing this pest in the Pacific Northwest, and little understanding of this insect's threat potential, life history and population dynamics in the extensive areas of irrigated agriculture in the inland Northwest. Field sampling was continued for a second year to determine the incidence of BMSB, as well as native stink bugs on a set of native, weedy, and ornamental plants that are widespread in the Yakima Valley. This information generates hypotheses on hosts and preferred hosts of this recently introduced pest (Objective 1). Of note, Norway maple is now heavily used by BMSB in urban settings in eastern Washington. Additional laboratory assays demonstrated adult stink bug attraction responses to plant odors and to combinations of stink bug odor,pheromone, and plant odors. Pear psylla nymphs produce copious amounts of honeydew which causes fruit russeting, serves as a medium for the growth of sooty mold, and complicates harvest of pears. Scion wood taken from four pear varieties with resistance to pear psylla were grafted to rootstock and maintained in a greenhouse. To aid the development of new pear cultivars with insect resistance, these newly established trees will be used to identify mechanisms of resistance using stylet-pathway analyses and electronic penetration graphs. Field studies have been completed to determine whether defense elicitors used to control fire blight reduce populations of pear psylla. Results of these studies led to investigations to determine whether foliar antibiotics, also used for the control of fire blight, reduce endosymbionts of pear psylla and psyllid survival. A poor understanding of what shelter plants are most often used by overwintering psylla and cues that trigger overwintered psylla to return to pear orchards in spring complicates management practices targeting this bottlenecked population. Studies were initiated to develop a method using high-throughput direct sequencing for gut content analysis of pear psylla to identify which shelter plants are most suitable for overwintering psyllids. Winterform pear psylla were collected from shelter plants and pear orchards during winter and spring, and were stored at minus 80 degrees Celsius for gut content analysis after this new method is developed. To determine how winterform pear psylla locate pear trees in early spring, volatiles of budding pear trees were sampled and tested for evidence of attraction or aggregation by the insect. Understanding the role of natural enemies in orchards is made more complex with our realization that the natural enemy community in orchards and neighboring habitats includes species not previously known to occur in the Pacific Northwest. One important group of predators includes the minute pirate bugs, which are generalist predators of mites, psyllids, aphids, eggs and small larvae of caterpillars, and other soft-bodied arthropods. Almost 500 specimens of minute pirate bugs were obtained by loan from entomological museums in Canada, for use in updating northern distributions of native species. Additional specimens from ornamental plants were obtained from University of California, Riverside, to begin efforts at clarifying the taxonomically confusing mixture of species in Southern California and neighboring regions. Collecting efforts in Washington State and surrounding states are continuing. Specimens will be used to generate a list of external and anatomical traits that can be used to separate highly similar species. To reduce reliance on broad-spectrum pesticides, genetic control methods that are effective and environmentally sound need to be developed. One such method is to adapt clustered regularly-interspaced short palindromic repeats (CRISPR) CRISPR associated protein 9 (Cas9) genome editing for codling moth control. Two genes, one encoding an odorant receptor and one encoding a male dosage compensation protein, were edited with a CRISPR/ Cas9 genome editing system optimized for use in codling moth. Experiments to determine the effects of genome editing of these genes were performed. These included polymerase chain reaction amplification and sequencing, high resolution melt analysis, flight tunnel bioassays, and mating assays. Four additional odorant receptor genes were characterized and sites to target with CRISPR/Cas9 genome editing were identified. Guide ribonucleic acids (RNAs) to target each gene were designed and production templates were generated through PCR and in vitro transcription. These guide RNAs will be used in gene editing experiments to be performed in the next year. Identification and improvement of chemical attractants and traps for moth pests will enable development of attract-and-kill management approaches, and improve monitoring using attractive lures. Studies were conducted to address several components needed to develop a successful, efficacious attract and kill approach for codling moth and leafrollers. Flight tunnel studies compared the effectiveness of different trap liners with captured females to lure additional males to the trap. Studies were conducted to develop a liquid method to catch moths in bucket traps that combines the use of organic oil, vinegar, and propylene glycol. The interaction of several aromatic volatiles with the sex pheromones of leafrollers were evaluated. Mass trapping studies are currently in place in commercial orchards. Further field comparisons of volatile blends for codling moth and leafrollers are being investigated. We are also characterizing the volatiles released by various microbes that are both present in various host plants and in shoots damaged by aphids and leafroller larvae. The microbiome will be characterized, prominent species will be cultured and identified, and volatile emissions will be collected in an attempt to develop new attractants for leafrollers. Western cherry fruit fly is abundant in unmanaged cherries in irrigated areas in the dry interior of the Pacific Northwest of the U.S. Irrigation may allow pupae to survive in soil during hot summers when risk of heat stress and desiccation is greatest. The hypothesis that western cherry fruit fly pupae survive better in irrigated than non-irrigated soils and grassy soils in a dry habitat in Washington State was tested. We added water or no water to soil or grassy soil (25 percent sand, 6 percent clay, and 69 percent silt) in pots embedded in the ground to simulate irrigation and no-irrigation schedules in a three-year study. Larvae were dropped into the pots for pupation. Simulated irrigation did not increase pupal survival before winter in soil, but it increased survival in grassy soil. In one of three years, adult eclosion rates in spring and summer also followed this pattern. While irrigation broadens the distribution of western cherry fruit fly by allowing host cherry trees to survive in dry habitats, natural precipitation in central Washington appears sufficient for pupal survival. Non-irrigated grassy soil appears most detrimental to pupal survival. Observations of larval behaviors and pupation success as well as predators in this environment could help explain this unexpected finding. To improve attract-and-kill approaches for western cherry fruit fly management, studies are testing the use of Spinosad and Delegate insecticides with sugar or yeast plus sugar for control of western cherry fruit fly. Relative efficacy of treatments will be determined based on numbers of adult flies caught on sticky yellow traps and by larval infestation of cherries. Temperatures in the orchard are being monitored using data loggers placed on trees around the periphery of the test plot. In the next two years, the same protocol will be followed using trees not used previously. Pest risk analyses estimate the risk that an insect pest will become established in export countries, and are used to define terms in export negotiations. Critical limits to growth and development of codling moth, western cherry fruit fly, and apple maggot were determined to improve pest risk analyses for these pests. Differential scanning calorimety was used to determine the upper and lower thermal limits of non-diapausing 4th and 5th instar, diapausing 5th instar codling moth, diapausing apple maggot, and western cherry fruit fly. Whole body supercooling points and total water content of apple maggot and western cherry fruit fly, and reduction of thermal tolerance of western cherry fruit fly was also determined. Total lipid, carbohydrate, and protein analyses for diapausing pupae apple maggot and western cherry fruit fly following various cold storage and rearing conditions have also been completed. Ecological niche models based upon accurate biological data are important for development of pest risk analyses. Ecological niche models were developed for western cherry fruit fly, codling moth, Oriental fruit moth, and apple maggot. Ecological niche models for western cherry fruit fly are being revised with physiological and ecological parameters for European cherry fruit fly. These revised models will assist the Animal and Plant Health Inspection Service in preventing the spread of this pest from Ontario, Canada, to commercial cherry productions areas in the United States. Accomplishments 01 Knock-out of a pheromone receptor gene affects egg production and viability. The codling moth is a worldwide insect pest of apple and pear, and new methods that are safe and effective are needed to control it. ARS scientists in Wapato, Washington, used genomic technology to determine the function of an odorant receptor protein thought to be important in codling moth mating and reproduction. The gene encoding this odorant receptor was inactivated using clustered regularly- interspaced short palindromic repeats (CRISPR) CRISPR associated protein 9 (Cas9) genome editing. The results of this study revealed that inactivating this protein affected female codling moth's ability to lay viable eggs. Incorporating new strategies to inactivate this protein target in field populations will contribute to new and specific methods to control codling moth in the orchard. 02 An improved trapping system for Brown Marmorated Stink Bug (BMSB). The BMSB continues to spread, increase in numbers, and threaten a variety of crops. Improved detection and monitoring methods are needed to determine crop risks. ARS researchers in Wapato, Washington, in collaboration with scientists of Sterling International Inc. of Spokane, Washington, determined that a commercial pheromone lure deployed with a trap design used for paper wasps (TrapStik) yielded greater trap catches in comparison to pheromone-trap combinations currently in use. This development provides a more sensitive method of detecting Brown Marmorated Stink Bug populations. 03 Discovery of new biological control species in North America. The minute pirate bugs (Orius) are important sources of biological control in agricultural crops worldwide as predators of thrips, aphids, and mite pests. ARS scientists in Wapato, Washington, discovered that this group of predatory bugs in North America includes possibly four previously undescribed species which have been misidentified as one of our common described species. Specimens included one new species in agricultural regions of the Pacific Northwest, an undescribed species found in Southern California and Arizona feeding on thrips pests of ornamental plants, and possibly two undescribed species inhabiting native rangeland in Colorado and westwards into California, Oregon, and Washington. These results show that the minute pirate bug fauna in the Western U.S. is substantially more diverse than previously recognized, and that these predators are likely to contribute to biological control of a larger diversity of pest species than currently appreciated. 04 Defense elicitors suppress pear psylla populations. Pear psylla is the key insect pest of pear in the United States. This insect is primarily controlled using insecticides, and ongoing research seeks to discover new ways to manage this pest. Defense elicitors are foliar treatments which activate plant defenses leading to broad-spectrum immunity to numerous pests. ARS scientists in Wapato, Washington, tested the effects of three elicitors of plant defenses against pear psylla under field conditions. They found that the commercial elicitors, Actigard, Employ, and ODC, each reduce numbers of the damaging stage of pear psylla. These products are often used to control fire blight in pear orchards, and knowledge that these products reduce pear psylla will be useful for integrated pest management. 05 Development of gene editing using the codling moth maleless gene ortholog. Ribonucleic acid (RNA) interference has been useful for studying protein function in many insect species, however this technique is not very effective in lepidopteran insects, including the codling moth. ARS scientists in Wapato, Washington, developed clustered regularly-interspaced short palindromic repeats (CRISPR) CRISPR associated protein 9 (Cas9) gene editing technology for use in codling moth, a worldwide pest of apple and pear. The maleless gene ortholog was used as a model to develop and determine the effectiveness of CRISPR/Cas9 gene editing in codling moth. Optimizing egg injection techniques and timing, and guide RNA design led to a highly efficient gene editing system. Analysis of the deoxyribonucleic acid (DNA) sequences indicated that 85 percent of injected eggs exhibit genome modification of the targeted regions, and those modifications included both insertions and deletions. This success establishes our ability to perform the CRISPR/Cas9 genome editing in the codling moth. 06 Suitability of mango and other tropical and temperate fruit as hosts for apple maggot and cherry fruit flies. Apple maggot and western cherry fruit flies are quarantine pests of apple and sweet cherry, respectively, in the Pacific Northwest of the United States, but the flies have narrow host ranges that may reduce their threat to a wider range of fruit commodities. ARS scientists in Wapato, Washington, and scientists at Washington State University in Vancouver, Washington, tested the hypothesis that these flies do not utilize tropical fruit as hosts. In Washington, apple maggot flies infested only one percent of mangoes and zero percent of papayas hung in trees compared with forty- nine percent of apples. Cherry fruit fly infested only six percent of mangoes and zero percent of papayas versus thirty-three to seventy- three percent of cherry and plum in the laboratory. The low acceptability of mango and other tropical fruit provide evidence they would unlikely be attacked even if the flies were to be introduced into a tropical environment. 07 Impact of prolonged absence of low temperature on emergence patterns of western cherry fruit fly. The western cherry fruit fly is a quarantine pest of sweet cherries in the Pacific Northwest that is adapted to cold winters. The ability of this pest to establish and spread to markets in warm countries is affected by its ability to survive in warm temperatures. ARS researchers in Wapato, Washington, conducted a 3-year study to examine the effects of prolonged no chilling on fly emergence. It was found that a lack of chilling of diapausing pupae reduced the number of flies that emerged and delayed emergence times but did not completely prevent fly emergence. Results are important in that they can be used to develop revised models to predict fly emergence in warm climates. 08 Responses of snowberry and apple maggot flies to commercial and experimental sticky traps and odors. The apple maggot fly is a threat to the commercial apple industry in the Western U.S., requiring trapping surveys to detect its presence. A similar non-pest fly species, the snowberry maggot fly, is also caught on survey traps, increasing labor needed to process fly catches. ARS scientists in Wapato, Washington, and scientists at Washington State University, Vancouver, Washington, University of Notre Dame, Indiana, and Cornell University, New York, compared responses of the two flies to various traps and odors to identify best practices for reducing snowberry maggot fly captures in surveys. It was found that snowberry maggot flies responded more to sticky yellow rectangle than sticky red sphere traps, while the reverse was true for apple maggot flies. Snowberry maggot flies did not respond to apple odors attractive to apple maggot flies, but rather to snowberry fruit odors, while both species were attracted to ammonia odor. Our results are important in that they provide evidence that red spheres with apple or ammonia odor are better to use than yellow rectangles in apple maggot fly trapping surveys where snowberries are abundant. 09 Attraction of western cherry fruit fly to white light in the presence and absence of ammonia. Western cherry fruit fly is a quarantine pest of sweet cherry in the Pacific Northwest that can be detected using sticky yellow traps. Identifying factors that can increase the efficacy of traps baited with ammonia can be useful for improving fly management. ARS scientists in Wapato, Washington, determined if flies are attracted to white light from bulbs and whether light can be used to enhance fly captures in the field. In the laboratory, it was found that flies were attracted to bright white light in the presence and absence of ammonia odor. In the field, flies were not attracted to white light when ammonia odor was present, but they were when it was absent. Results are important in that they show responses to white light could partly explain fly behaviors and efficacies of traps. 10 Identification of host fruit volatiles from snowberry attractive to flies from snowberry in Washington State. Apple maggot fly is a pest of apples whose responses to fruit volatiles have been well studied, helping us understand the process of speciation in insects that attack plants. However, responses by a similar fly, Rhagoletis zephyria, to chemicals from host fruit have never been studied. ARS scientists in Wapato, Washington, and scientists at Cornell University in New York, University of Notre Dame in Indiana, Portland State University in Oregon, and Western Washington University in Washington, used gas chromatography and electroantennogram detection (EAD) to identify volatiles from the fruit of snowberry as key attractants for R. zephyria flies reared from snowberry fruit. A nine-component blend was identified that gave consistent EAD activity, and in a flight tunnel, snowberry flies displayed more flight to sources with snowberry than apple and hawthorn fruit volatiles. Findings provide evidence that differences among flies in their behavioral responses to host fruit odors represent key adaptations involved in host plant shifts. 11 Plant volatiles attractive to orchard moth pests. Discoveries of new attractive blends of plant volatiles for a diversity of orchard moth pests can allow improved pest management in these crops. ARS researchers in Wapato, Washington, found that two plant aromatics, when used with acetic acid, are effective attractants for both sexes of several leafroller species. It was discovered that either compound used in combination with a synthetic sex pheromone lure significantly reduces male catch compared with the pheromone alone. Adding acetic acid to these traps can increase the male catch to nearly comparable levels as the pheromone alone and allows female moths to be captured. This knowledge advances our development of lure and kill technologies for this important group of pests. 12 Collection of psyllid saliva. Salivary proteins have important roles in feeding by insects, but there are currently no published studies on the salivary proteins of psyllids. ARS scientists in Wapato, Washington, and Stillwater, Oklahoma, and scientists at Heritage University in Toppenish, Washington, developed methods to collect large quantities of salivary proteins from potato psyllid and pear psylla. These methods allow researchers to collect, identify and analyze salivary proteins of psyllid pests in pears and in other crops. This information leads to a better understanding of how psyllids feed and transmit plant pathogens.
Impacts
(N/A)
Publications
- Cooper, W.R., Garczynski, S.F., Horton, D.R., Unruh, T.R., Beers, E., Shearer, P., Hilton, R. 2017. Bacterial endosymbionts of the psyllid Cacopsylla pyricola in the Pacific Northwestern United States (Hemiptera: Psyllidae). Environmental Entomology. 46:393-402.
- Cooper, W.R., Horton, D.R. 2017. Elicitors of host plant defenses partially suppress pear psylla (Cacopsylla pyricola, Hemiptera: Psyllidae) populations under field conditions. Journal of Insect Science. 17(2):49.
- Beers, E., Horton, D.R., Miliczky, E. 2016. Pesticides used against Cydia pomonella disrupt biological control of secondary pests of apple. Biological Control. 102:35-43.
- Beers, E., Mills, N., Shearer, P., Horton, D.R., Miliczky, E., Amarasekare, K., Gontijo, L. 2016. Nontarget effects of orchard pesticides on natural enemies: lessons from the field and laboratory. Biological Control. 102:44- 52.
- Giacomuzzi, V., Cappellin, L., Nones, S., Khomenko, I., Knight, A.L., Biasiolo, F., Angeli, S. 2017. Diel rhythms in the volatile emission of apple and grape foliage. Phytochemistry. 138:104-115.
- Neven, L.G., Yee, W.L. 2017. Impact of prolonged absence of low temperature on adult eclosion patterns of western cherry fruit fly (Diptera: Tephritidae). Environmental Entomology. 46(3):708-713.
- El-Sayed, A., Knight, A.L., Byers, J., Judd, G., Suckling, D. 2016. Caterpillar-induced plant volatiles attract conspecific adults in nature. Scientific Reports. doi:10.1038/srep37555.
- Yee, W.L., Goughnour, R. 2017. Development of Rhagoletis pomonella and Rhagoletis indifferens (Diptera: Tephritidae)in mango and other tropical and temperate fruit in the laboratory. Florida Entomologist. 100(1):157- 161.
- Yee, W.L. 2017. Attraction of Rhagoletis indifferens (Diptera: Tephitidae) to white light in the presence and absence of ammonia. Florida Entomologist. 100(1):21-28.
- Garczynski, S.F., Martin, J.A., Griset, M.L., Willett, L.S., Cooper, W.R., Swisher, K.D., Unruh, T.R. 2017. CRISPR/Cas9 editing of the codling moth (Lepidoptera: Tortricidae) CpomOR1 gene affects egg production and viability. Journal of Economic Entomology. 110(4):1847-1855.
- Landolt, P.J., Cha, D.H., Zack, R.S. 2015. Synergistic trap response of the false stable fly and little house fly (Diptera: Muscidae) to acetic acid and ethanol, two principal sugar fermentation volatiles. Environmental Entomology. 44(5):1441-1448.
- Kumar, S., Neven, L.G., Zhu, H., Zhang, R. 2015. Assessing the global risk of establishment of Codling moth (Cydia pomonella) using CLIMEX and MaxEnt niche models. Journal of Economic Entomology. 108(4):1708-1719.
- Cha, D., Olsson, S., Yee, W.L., Goughnour, R., Hood, G., Mattsson, M., Schwarz, D., Feder, J., Linn, C. 2017. Identification of host fruit volatiles from snowberry (Symphoricarpos albus), attractive to Rhagoletis zephyria flies from Western United States. Journal of Chemical Ecology. 43(2):188-197.
- Giacomuzzi, V., Mattheis, J.P., Basoalto, E., Angeli, S., Knight, A.L. 2017. Survey of conspecific herbivore-induced volatiles from apple as possible attractants for Pandemis pyrusana (Lepidoptera: Tortricidae). Pest Management Science. doi:10.1002/ps.4548.
- Giacomuzzi, V., Cappellin, L., Khomenko, I., Biasioli, F., Schutz, S., Tasin, M., Knight, A.L., Angeli, S. 2017. Emission of volatile compounds from apple plants infested with Pandemis heparana larvae, antennal response of conspecific adults, and preliminary field trial. Journal of Chemical Ecology. 42:1265-1280.
- Jones, V., Horton, D.R., Mills, N., Unruh, T.R., Miliczky, E., Shearer, P., Baker, C., Melton, T. 2016. Using plant volatile traps to develop phenology models for natural enemies: an example using Chrysopa nigricornis (Burmeister) (Neuroptera: Chrysopidae). Biological Control. 102:77-84.
- Knight, A.L., Judd, G., Basalto, E. 2017. Development of 2-phenlethanol and acetic acid lures to monitor Obliquebanded leafroller (Lepidoptera: Tortricidae) under mating disruption. Journal of Applied Entomology. doi:10.1111/jen.12393.
- Mills, N.J., Beers, E.H., Shearer, P.W., Unruh, T.R., Amarasekare, K.G. 2016. Comparative analysis of pesticide effects on natural enemies in western orchards: a synthesis of laboratory bioassay data. Biological Control. 102:17-25.
- Unruh, T.R., Miliczky, E., Horton, D.R., Thomsen Archer, K.L., Rehfield- Ray, L.M., Jones, V. 2016. Gut content analysis of arthropod predators of codling moth in Washington apple orchards. Biological Control. 102:85-92.
- Jones, V., Unruh, T.R., Horton, D.R., Mills, N., Brunner, J., Beers, E., Shearer, P. 2009. Tree fruit IPM programs in the Western United States: the challenge of enhancing biological control through intensive management. Pest Management Science. 65:1305-1310.
- Landolt, P.J., Zhang, Q. 2016. The discovery and development of chemical attractants used to trap pestiferous wasps (Hymenoptera: Vespidae). Journal of Chemical Ecology. 42:7.
- Cha, D.H., Adams, T., Landolt, P.J. 2017. Effect of chemical ratios of a microbial-based feeding attractant on trap catch of spotted wing drosophila (Diptera: Drosophilidae). Environmental Entomology. 46(4):907- 915.
- Derstine, N., Ohler, B., Jimenez, S., Landolt, P.J., Gries, G. 2017. Evidence for sex pheromones and inbreeding avoidance in select North America yellowjacket species (Hymenoptera: Vespidae). Entomologia Experimentalis et Applicata. doi:10.1111/eea12591.
- Kumar, S., Yee, W.L., Neven, L.G. 2016. Mapping global potential risk of establishment of Rhagoletis pomonella (Diptera: Tephritidae) using MaxEnt and CLIMEX niche models. Journal of Economic Entomology. 109(5):2043-2053.
- Yee, W.L. 2016. Ammonium carbonate loss rates from lures differentially affect trap captures of Rhagoletis indifferens (Diptera: Tephritidae) and non-target flies. The Canadian Entomologist. 149:241-250.
- Yee, W.L., Goughnour, R.B. 2016. Peach is an occasional host for Rhagoletis pomonella (Walsh, 1867) (Diptera: Tephritidae) larvae in Western Washington State, USA. Pan-Pacific Entomologist. 92(4):189-199.
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Progress 10/01/15 to 09/30/16
Outputs
Progress Report Objectives (from AD-416): This research will provide basic and applied information for the development and transfer of sustainable and environmentally acceptable methods and technologies for management of insect pests of temperate tree fruit crops. The objectives are: Objective 1: Develop new knowledge of the behavior, physiology, ecology, and biochemistry of insect pests and their natural enemies to suggest novel approaches to pest management and improve the use of existing methods, with focus on pest-host plant interactions of pear psylla and brown marmorated stink bug, pest-microbe interactions of codling moth and spotted wing drosophila, ecological and physiological criteria that limit pest distribution and abundance, and the functionality of codling moth receptors. Subobjective 1A. Determine and characterize interactions between pear trees and pear psylla and between the brown marmorated stink bug (BMSB) and preferred host plants. Subobjective 1B. Determine if volatiles emanating from microbial species found in the honeydew of aphids, mealybugs and psyllids are attractive to natural enemies. Subobjective 1C. Determine factors affecting pupal mortality and adult emergence of western cherry fruit fly (WCFF) in the field. Sub-objective 1D. Determine the upper and lower thermal limits for metabolism of different life stages of codling moth (CM), apple maggot (AM), and WCFF. Subobjective 1E. Develop a CRISPR/Cas9 gene knock out system to determine functions of proteins key to CM reproduction and development. Subobjective 1F: Determine undescribed cryptic species and undocumented range expansions of the community of minute pirate bugs in orchards and other habitats. Objective 2: Develop alternatives to fumigation to meet quarantine restrictions for pest insects in exported fruits, with focus on developing codling moth detector technology and ecological niche modeling to determine limits to the establishment and spread of quarantined insect pests. Subobjective 2A: Identify biochemical markers for apple fruit infested with CM larvae, in support of effort to develop detector technology. Subobjective 2B: Improve ecological niche models for the potential of tree fruit pests of quarantine concerns to establish and spread in potential new export markets. Objective 3: Develop and improve methods to reduce pesticide use and develop alternatives to pesticides, with focus on identifying and applying semiochemicals for pest management, and improved efficacy of natural enemies through application of foods and feeding attractants, and improvement of pear psylla control through induced or systemic acquired resistance in pear to psylla. Subobjective 3A. Develop an attract-and-kill approach for management of codling moth and leafrollers. Subobjective 3B. Improve efficacy of natural enemies through application of foods and feeding attractants. Subobjective 3C. Determine field temperature influences on the efficacy of the insecticide spinosad and Delegate for management of WCFF. Subobjective 3D. Improve pear psylla control through induced or systemic acquired resistance. Subobjective 3E. Evaluate the use of microbial-based feeding attractants for management of codling moth. Approach (from AD-416): 1A. Plant resistance to pear psylla will be characterized using greenhouse and biochemical assays and electrical penetration graphs. Host preferences by brown marmorated stink bug will be assessed by determining patterns of host plant use in non-crop landscapes. Stink bug attraction to host odor will be tested using a laboratory olfactometer. 1B. To develop methods of recruiting natural enemies to orchards, microbes present in aphid and pear psylla honeydew will be identified, and odors emanating from honeydew-associated microbes will be tested for attractiveness to natural enemies. 1C. Western cherry fruit fly adult emergence will be compared from soils with varying moisture and cover to determine whether fruit fly infestations in orchards can emanate from trees located in unmanaged habitats with dry soil surfaces. 1D. Data from differential scanning calorimetry and laboratory assays will provide estimates of metabolic thermal limits for codling moth, apple maggot, and western cherry fruit fly to determine the liklihood for these pests to establish and spread in new geographies. 1E. A CRISPR/Cas9 gene knock out system will be used to determine the function of proteins key to codling moth reproduction and development in support of work to develop species-specific behavioral and physiological modifying analogs for use in pest management. 1F. To improve conservation biological control in orchards, undescribed cryptic species and undocumented range expansions of minute pirate bugs in orchards and other habitats will be described based on morphometric analyses and molecular genetics. 2A. In support of efforts to develop technology to detect codling moth infestations in stored fruit, biochemical markers for infested apples will be identified using GC-MS, and laboratory studies will be used to determine how long marker chemicals are emitted from infested fruit. 2B. Experiments conducted in environmental chambers will be used to determine the effects of tropical and sub-tropical climates and photoperiods on the growth and development of codling moth, western cherry fruit fly, and apple maggot. Data will be used to improve ecological niche models for tree fruit pests of quarantine concerns to estimate the risk for these pests to establish and spread in export markets. 3A. New attractant blends will be developed as an attract-and-kill or mass trapping approach for management of codling moth and leafrollers. 3B. Plant-based attractive lures and food provisioning will be tested as attract-and-retain method of improving biological control in orchards. 3C. Effects of temperature on the efficacy of the insecticides Spinosad and Delegate for management of western cherry fruit fly will be determined using laboratory assays. 3D. Greenhouse assays and field studies will be used to test whether elicitors of host plant defenses can be used for the control of pear psylla. 3E. Laboratory studies will be performed to determine whether the addition of different yeast species with cane sugar stimulate codling moth feeding and increase the efficacy of ingested microbial or chemical insecticides against codling moth. This is the first report for this new project which began on October 26, 2015 and continues research from the previous project, �Biorational Management of Insect Pests of Temperate Tree Fruits�, 2092-22430-001-0D. Substantial progress was made for all sub-objectives of Objective 1, to develop new knowledge of the biology of insect pests and their natural enemies. Sub-objective 1A: Stink bugs were collected in 67 samples of natural and suburban vegetation to develop hypotheses on the habitats and types of plants used by a number of pest stink bugs, including brown marmorated stink bugs. In dry non-agricultural areas, plants that are succulents and plants with fruits accounted for most phytophagous stink bugs sampled. Brown marmorated stink bug distributions remained strictly urban. Sub-objective 1B: Surveys were conducted to identify microbial species colonizing aphid honeydew in apple and pear orchards. Microbes associated with sentinel Petunia and Nicotiana flowers deployed in orchards and riparian areas were also surveyed. A total of 40 bacterial species from 16 genera were identified by sequencing 16S rDNA. Volatiles produced by these microbes were tested for their attractiveness to assorted insect group in field trapping trials. These trapping trials showed that small Drosophila, Noctuid moths, beneficial parasitoids in the Ichneumonidae, and Vespid wasps were attracted to microbe-associated volatiles. Sub-objective 1C: Experiments on Western cherry fruit fly were conducted to determine the effects of moist vs. dry soil and bare ground vs. grass cover on pupal mortality and adult emergence. Preliminary studies indicated that unlike some other fruit flies, pupal Western cherry fruit flies are tolerant of dry soil and dry grass and are well adapted to climates with little moisture during the summer. Flies emerged significantly earlier from bare soil than from grass, but total emergence was not consistently different. Results may help explain the current distribution of Western cherry fruit fly, and may be useful for predicting their potential establishment in other regions of the world. Sub-objective 1D: The upper and lower thermal limits of Western cherry fruit fly adults and pupae were determined by measuring oxygen consumptions and metabolic rates of insects under a range of temperatures. Results indicated that as adult flies age, their range of thermal tolerance decreases. Also, overwintering pupae remain resistant to freezing until just before they emerge as adult flies. Sub-objective 1E: A genome editing system to study protein function was developed for codling moth. Experiments to optimize the amount of genome editing were performed. Preliminary studies indicated that we have developed a functional CRISPR/Cas9 technique for use in codling moth that creates gene mutations with high efficiency. This gene editing tool will allow researchers to characterize the proteins involved in the molecular mechanisms of codling moth host or mate finding behaviors. Sub-objective 1F: Over 1,000 specimens of minute pirate bugs have been obtained during our own collecting efforts and as loans to us from University and USDA entomology museums. The specimens are in the process of being sorted and carefully examined, with final objectives being to produce a new key to the minute pirate bugs of North America. Traits under examination include color, external morphology, and size and form of the male and female genitalia. On-loan specimens are being re-labeled with correct identifications in the event that the loaned specimen was misidentified. Progress was also made in subordinate projects highly related to Objective 1: A set of compounds in wine and produced by yeasts were tested as attractants for Polistes paper wasps, as part of an effort to mitigate problems with these wasps at Air Force Bases. Although the work is ongoing, results are promising with a 250% improvement in the catch of these wasps in traps compared to current technology. Additionally, a second set of these yeast-produced compounds was found to be attractive to yellowjacket wasps. In another subordinate project, pear psylla were collected from Washington and Oregon to survey populations for associated bacterial endosymbionts. Two bacteria - Arsenophonus and Phytoplasma pyri - were present in a large number of insects. Results of laboratory experiments suggest that Phytoplasma decreases fecundity and mobility of psylla. Future experiments will investigate the effects of Arsenophonus on psylla biology. Progress was made for both sub-objectives of Objective 2, to develop alternatives to fumigation to meet quarantine restrictions for pest insects in exported fruits. Sub-objective 2A: Preliminary assessment has been made of volatile compounds emitted by mature apple. This information will provide a basis for comparison with fruit infested by codling moth to identify biochemical markers for infested apples. Sub-objective 2B: Studies have been initiated to improve ecological niche models for codling moth and Western cherry fruit fly to better estimate establishment and spread of these pests in export markets. To support these models, extensive field surveys for codling moth and Western cherry fruit fly were completed, and synthesis of available data on the public database, Pestworld, has been completed. Progress was made for most sub-objectives of Objective 3, to develop and improve methods to reduce pesticide use and to develop alternatives to pesticides. Sub-objective 3A: Field tests have confirmed control of codling moth in apple orchards with kairomone-baited traps at 50 traps per acre. Thirty- day tests of trapping out codling moths in 4 acre plots showed 70+% reductions in new damage to the crop over this time frame. Laboratory studies of release rates of these kairomone compounds provided a sachet dispenser system to replace the more expensive vial system. The new sachet dispenser was validated as equally attractive when tested as a lure in traps in field trials. Initial moth retention and influence of field-aging was compared among different adhesive trap liners used in mass-trapping approaches for codling moth and leafrollers. Results indicate that different trap liners vary in mass-trapping efficacy. A non- saturating bucket trap filled with certified-organic mineral oil or propylene glycol for non-organic orchards caught ten-times more moths and required less labor than the standard sticky trap with removable liners. Sub-objective 3B: Studies have been initiated to attract and retain natural enemies in orchards using plant derived volatiles and supplemental foods sources. Sub-objective 3C: A first set of experiments testing the effects of three temperatures on kill and oviposition of flies exposed to the insecticides spinosad (Entrust) and spinetoram (Delegate) was completed. Accomplishments 01 Development of an inexpensive kairomone dispenser system for use in codling moth mass trapping. Codling moth is a key pest of apple, pear, and walnuts in the United States and elsewhere in the world. New approaches and technologies, such as mass trapping with lures for female moths, are needed to replace pesticide applications and to augment mating disruption which is in widespread use. ARS scientists in Wapato, Washington, developed an inexpensive sachet system for providing optimized controlled release of acetic acid, a fruit volatile, and pear ester as a lure for female and male codling moths. Field tests validated the attractiveness and performance of the new dispenser system as a lure for traps. Previous and parallel research demonstrated control of codling moth damage at 50 kairomone-baited traps per acre, and reduced costs for lures and traps will benefit growers adopting this approach. These developments show promise as new technologies for the control of codling moth by conventional and organic fruit growers. 02 Identification of ammonium carbonate loss rates that maximize catches of Western cherry fruit fly while minimizing non-target insect captures. Western cherry fruit fly is a quarantine pest of sweet cherry in the Pacific Northwest of the U.S. that can be monitored using traps baited with ammonia. However, ammonia-based attractants also attract non- target flies that clutter traps and reduce trap efficiency. ARS researchers in Wapato, Washington, determined whether ammonium carbonate (AC) loss rates from lures differentially affect numbers of cherry fruit fly and non-target flies caught on sticky yellow traps in cherry trees. Results showed that lures with an AC loss rate of 0.19 mg/ hour maintained high cherry fruit fly captures while reducing non- target fly captures. This rate thus should be used for monitoring cherry fruit flies in areas where there are many non-target flies. 03 Effectiveness of benzoid plant volatiles plus acetic acid to monitor Obliquebanded leafroller in apple orchards under mating disruption. Effective, low-cost monitoring of tree fruit pests is an important component of developing integrated programs which can minimize the use of insecticides. ARS researchers in Wapato, Washington, in collaboration with researchers in Chile and Canada developed a new lure for obliquebanded leafroller and compared it with a sex pheromone lure in orchards treated with sex pheromone. It was determined that the new lure was more effective than the sex pheromone lure and caught both sexes. Information from this research supports the continued effort to develop even more effective lures that can be used in trap-based monitoring program for important moth pests in tree fruits. 04 Mapping global potential risk of establishment of Rhagoletis pomonella (Diptera:Tephritidae) using MaxEnt and CLIMEX niche models. The apple maggot is a major quarantine pest of apples in the U.S. To reduce the threat of apple maggot to export countries and to facilitate the movement of commercial apples, an assessment of potential risk of establishment of apple maggot in export countries is needed. ARS researchers in Wapato, Washington, and Colorado State University in Fort Collins, Colorado, used the predictive models MaxEnt and CLIMEX to determine global potential risk of establishment of apple maggot. Both models correctly predicted the known distribution of apple maggot in North America and mostly agreed on climatic suitability worldwide for the fly. Our results are important because they can be used to make science-based international trade decisions on apple movement by policy makers. 05 Taxonomic reassessment of the minute bug fauna of the western United States. The minute pirate bugs (Orius) are important sources of biological control in agricultural crops worldwide. ARS scientists in Wapato, Washington, found that the minute pirate bug fauna in western North America includes specimens whose body traits differ from traits of described species, suggesting that the minute pirate bugs of North America are actually a complex of described species and undescribed cryptic species. Body traits allowing identification of undescribed species were defined, and separation of species using these characteristics was confirmed by an analysis of DNA-sequences. These results will help scientists, field biologists, and others interested in biological control to identify minute pirate bugs found in agricultural crops of western North America, leading to more efficient use of these species in biological control. Results additionally raised concerns about whether identifications of minute pirate bugs in the North American biological control literature may often be incorrect. 06 Reduction of optimal thermal range in aging western cherry fruit flies. The western cherry fruit fly is an economically important pest of sweet cherries in the western U.S., and may have potential to spread to new areas. This potential to invade other geographic areas is probably limited by intolerance to extreme temperatures resulting in a shutdown of metabolic activity and development. This can be measured as its oxygen consumption and metabolic rate. ARS scientists in Wapato, Washington, determined that the fly tolerance of temperature extremes is impacted by the age of the fly. Newly emerged flies showed the broadest tolerance to temperatures, maintaining metabolic activity from 6.6 to 42.2 degrees Celsius (a range of 35.8 degrees), and fly tolerance to temperature variation was reduced with age; 28-day old flies showed the shortest range of temperatures suitable for metabolic activity from 10.5 to 37.8 degrees Celsius (a range of 27.2 degrees). These results were used to refine a model to predict the potential distributions of this pest on national and global bases, which in turn is being used by the northwest sweet cherry industry to renegotiate current and establish new trade agreements where quarantine restrictions exist against the western cherry fruit fly and the models show no risk of invasion. 07 How far south can codling moth spread in China? Potential distribution and stages of invasion are critical information. Codling moth, Cydia pomonella, is a major quarantine pest of apples in the U.S and several other countries. Although codling moth originally developed in central Asia Minor, most likely Kazakhstan, it was not reported in China until 1953. ARS scientists in Wapato, Washington, and scientists at Colorado State University in Fort Collins, Colorado and the Institute of Zoology, Chinese Academy of Sciences in Beijing, China, collaborated to model the stages of invasion of this pest in China as well as identifying those areas most at risk of invasion by this pest. The model accurately predicted the progression of codling moth using 2010 data and comparing to 2015 currently infested areas. The revised model showed those regions most at risk of invasion by this pest and showed areas of invasion stages of population stabilization, colonization, adaptation, and sink. These data will be used to develop improved, environmentally sustainable monitoring and management practices in China, which will help to stem the spread of this pest on a global level as exports of Chinese apples increase. 08 Improved trapping of pestiferous paper wasps on Air Force Bases. Several species of Polistes wasps cause problems at Air Force Bases in the Southeast U.S., both as a stinging hazard at base housing, but more importantly within Air Traffic Control towers where they form mating and overwintering swarms in autumn. ARS scientists in Wapato, Washington, Gainesville, Florida, and Poplarville, Mississippi, working with scientists at Sterling International Inc. of Spokane, Washington, and the Tyndall and Moody Air Force Bases in Florida and Georgia respectively, developed a new combination lure-and trapping system that is far more effective than previous systems tested, and discovered a yeast-produced chemical that improves the catch of these wasps on traps by 250%. Testing of chemicals as attractants continues, but these results provide improved means to manage wasp populations in limited areas where they are pestiferous. 09 Identification of bacterial endosymbionts associated with pear psylla. Pear psylla is a key pest of pear in the western United States. Psyllids are often associated with bacterial endosymbionts that can alter the insects' susceptibility to parasitism, insect pathogens, and insecticides. ARS scientists in Wapato, Washington, screened pear psylla populations in the Pacific Northwest for bacterial endosymbionts. They found that all populations carry the endosymbiont Arsenophonus, which provides another psyllid pest with protection against parasitism. They also found that Phytoplasma pyri, a pathogen associated with pear decline disease and yellow peach leafroll disease, was more prevalent in psylla populations in the Yakima Valley than in other regions. This study is the first to characterize the diversity of endosymbionts of pear psylla in North America.
Impacts
(N/A)
Publications
- Galdino, T., Kumar, S., Oliveira, L., Alfenas, A., Neven, L.G., Al-Sadi, A. , Picanco, M. 2016. Mapping global potential risk of mango sudden decline disease caused by fungus Ceratocystis fimbriata. PLoS One. 11(7):e0159450.
- Cooper, W.R., Horton, D.R. 2015. Effects of elicitors of host plant defenses on pear psylla (Cacopsylla pyricola: Psyllidae). Entomologia Experimentalis et Applicata. 157:300-306.
- Walker, W.B., Gonzalez, F., Garczynski, S.F., Witzgall, P. 2016. The chemosensory receptors of codling moth Cydia pomonella � expression in larvae and adults. Scientific Reports. doi: 10.1038/srep23518.
- Neven, L.G., Hale, A. 2015. Use of scanning calorimetry and microrespiration to determine effects of Bt toxin doses on Pandemis leafroller (Lepidoptera: Tortricidae) metabolism. Trends in Entomology. 11:39-46.
- Yee, W.L., Alston, D.G. 2016. Sucrose mixed with spinosad enhances kill and reduces oviposition of Rhagoletis indifferens (Diptera: Tephritidae) under low-food conditions. Journal of Entomological Science. 51(2):101-112.
- Yee, W.L., Klaus, M. 2015. Implications of Rhagoletis zephyria, 1894 (Diptera: Tephritidae), captures for apple maggot surveys and fly ecology in Washington state, U.S.A. Pan-Pacific Entomologist. 91(4):305-317.
- Horton, D.R., Lewis, T.M., Garczynski, S.F., Thomsen Archer, K.L., Unruh, T.R. 2016. Morphological and genetic reappraisal of the Orius fauna of the western United States (Hemiptera: Heteroptera: Anthocoridae). Annals of the Entomological Society of America. doi: 10.1093/aesa/sav155.
- Wang, J., Gu, L., Ireland, S., Garczynski, S.F., Knipple, D.C. 2015. Phenotypic screen for RNAi effects in the codling moth Cydia pomonella. Gene. 572:184-190.
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