Recipient Organization
TEXAS A&M UNIVERSITY
750 AGRONOMY RD STE 2701
COLLEGE STATION,TX 77843-0001
Performing Department
Entomology
Non Technical Summary
The European pepper moth (EPM) (Duponchelia fovealis) is a major, yet largely unrecognized exotic invasive insect pest of nursery, vegetable, fruit, and greenhouse crops. Larval EPM feed on foliage, fruit, and frequently on lower stems of plants, causing stem dieback, plant death, and economic loss, with several growers estimating an annual economic lossgreater than $200,000 from EPM. Current management strategies are ineffective, because information about EPM distribution, population cycles, plant preferences, and effective insecticides is lacking. Extension personnel, growers, the IR-4 Project, and trade associations have recognized EPM as one of the top priority pests that needs to be addressed. This multi-state project (TX and NC) spans across a large area of the EPM range, providing data and insight relevant to southern USA. The purpose of this proposal is to increase adoption of effective integrated pest management (IPM) practices and decrease economic loss due to EPM by investigating the following objectives: (1) determine the distribution and phenology of EPM; (2) determine EPM preference and damage to nursery crop species and cultivars; (3) determine how irrigation and fertilizer practices can influence damage caused by EPM; and (4) determine the efficacy of standard and biological insecticides to manage EPM. Results from this study will be published in peer-reviewed papers, industry magazines, university extension articles, websites, and through EDDMaps.
Animal Health Component
100%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Goals / Objectives
The over-arching goal is to increase our understanding of the European Pepper Moth,Duponchelia fovealis, seasonal population dynamics, preferred host plants, and effective management strategies. Our intent is to equip growers with the knowledge and tools necessary to effectively manage and decrease the economic impact of the European Pepper Moth in greenhouse and nursery production. We plan to achieve this goal through three primary objectives:Objective 1. Determine the distribution of EPM across the US and phenology in the southern region.Methods:To determine the distribution of EPM, we will leverage resources developed by the University of Georgia's Center for Invasive Species and Ecosystem Health EDDMaps (eddmaps.org; letter of support included) to track the current and future distribution of EPM. An online training module will be developed to train master gardeners, county agents, growers, and other green industry professionals on how to recognize EPM larvae, signs of EPM damage, how to use EPM pheromone traps, and how to report to EDDMaps. The training will be provided via live webinar and a recording hosted on YouTube. The PI and co-PI of this proposal will serve as the verifiers for submissions submitted to EDDMaps. We have used a similar approach for training citizen scientists to report pollinator abundances (over 19,000 contributions in 2020 alone;sixleggedaggie.com/pollinator-project) and report sightings of crape myrtle bark scale (stopcmbs.com), another invasive insect pest. We will trap EPM adults and collect larvae for two years to determine seasonal abundance and flight activity of EPM. Although degree-day models have been developed for EPM, they were conducted in controlled-diet lab settings and were poorly correlated with seasonal abundance of EPM collected with pheromone traps. We will trap EPM near high resolution weather stations in 3 nursery production regions of TX and NC to document EPM activity in different climate regions throughout each state. For example, in NC traps can be placed in nurseries in the eastern coastal region (<100' elevation), central and southern piedmont regions (100-900'), foot hills (900-1500'), or mountains (1500-3500'). Two water pan traps, shown to be optimal for this pest, with EPM pheromone will be placed at each site with pheromones replaced per manufacturer recommendations (http://www.agbio-inc.com/). Traps will be collected every two weeks year-round with help from extension agents and cooperating nurseries to count EPM adults.Objective 2. Determine EPM preference for, and damage to, nursery crop species and cultivars common to NC, TX, and throughout the southern region.In years 1 and 2 we will visit 3 nurseries in each state three separate times during the growing season (late spring, summer, and fall). Each visit we will inspect three cultivars of three EPM host plants, azalea, rose, and loropatelum (NC) or hydrangea (TX) that are grown throughout the south. At each nursery we will inspect the foliage and surface of the media for EPM eggs, larvae, and webbing. We will also tip each plant from its pot to inspect the surface of the root ball. We will also rate EPM damage as percent of plant canopy affected (leaf damage, stunting, wilting), presence/absence of stem girdling, and assign a marketability rating using a <10% damage thresholdfor the most marketable plants (rating of 1), 10-25% as potentially marketable (rating 2), or unmarketable (3). We will also record irrigation type (e.g., overhead hand, overhead sprinkler, drip), fertilizer type and rate, insecticide regimen, and the wholesale and market value for each commodity inspected, as reported by the grower. To determine differences in feeding preferences, we will conduct laboratory feeding preference assays in TX. We will select 3 cultivars each of 8 woody plant species and 5 herbaceous species to examine EPM preference and potential as hosts. To be sure our work has regional importance we will focus on species and cultivars that are most common and economically important throughout the south based on the southern nursery Crop Profile and Pest Management Strategic Plans, and demonstrated susceptibility from field monitoring in objective 1. For each species we will place a leaf from each of three cultivars in a petri dish with moist filter paper and 5 EPM larvae. This will be replicated 20 times for each species. We will inspect each dish after 1, 4, 8, and 24 hours to record the total percent of leaves consumed (species total) and the percent of each cultivar consumed to determine if some susceptible species have less susceptible cultivars. EPM is an extreme generalist based on the number of plant species and families on which it feeds. It is important to determine if variation in susceptibility exists among cultivars and if it is enough to make a difference in commercial production. Finally, to compile a broad list of susceptible plants and cultivars we will survey growers at extension events. After presentations to educate growers on EPM and IPM we will use online or in person survey tools (depending if presentation is remote or in-person) to request lists of species and cultivars they have found to be most infested and most damaged by EPM. These grower observations will be compiled with, experimental results, and observations from the PIs and extension professionals to rank species susceptibility in each state. This list should be relevant to most of the south based on the more southern and northern locations of TX and NC.Objective 3. Determine the efficacy of standard and biological insecticides and application strategies for EPM management in commercial production;Methods: The most recent report of insecticide efficacy for managing EPM, prior to Frank and Nagle (submitted), described experiments from 2012-2015 (Bethke et al. 2017). We will conduct replicated experiments under commercial growing conditions to test the efficacy of relatively new insecticides in addition to older insecticides that are inexpensive and used regularly by growers. We will conduct two efficacy experiments (one in Texas and one in North Carolina) with 8 treatments (9 different insecticides, rates, or application procedure) and 6 replicates each. We will also include two treatments per location composed of biological insecticides and entomopathogenic nematodes. Active ingredients included in these experiments will include formulations of the entomopathogenic fungiBeauveria bassiana, Metarhizium spp.,andIsaria fumosoroseaand formulations of the bacteriaBacillus thuringiensis(Bt). We will also test commercially available entomopathigenic nematodes includingSteinernema carpocapsae,Steinernema feltiae, andHeterorhabditis bacteriophora.Plants will be infested from our colony with 12 larvae each prior to experiments or we will use naturally infested plants when they are available from cooperating growers. Live larvae and pupae will be counted by destructively sampling 3 replicate plants in each treatment 7 and 14 days after treatment. Longer experiments are difficult and unnecessary as larvae could mature and fly away as adults, destructive sampling requires many replicates, and products that do not work within 14 days are unlikely to be adopted by growers. We will also record plant aesthetic score rating (as in objective 3 above) 14 days after treatment application prior to destructive sampling.
Project Methods
Objective 1. Determine the distribution of EPM across the US and phenology in the southern region.Methods:To determine the distribution of EPM, we will leverage resources developed by the University of Georgia's Center for Invasive Species and Ecosystem Health EDDMaps (eddmaps.org; letter of support included) to track the current and future distribution of EPM. An online training module will be developed to train master gardeners, county agents, growers, and other green industry professionals on how to recognize EPM larvae, signs of EPM damage, how to use EPM pheromone traps, and how to report to EDDMaps. The training will be provided via live webinar and a recording hosted on YouTube. The PI and co-PI of this proposal will serve as the verifiers for submissions submitted to EDDMaps. We will trap EPM adults and collect larvae for two years to determine seasonal abundance and flight activity of EPM.We will trap EPM near high resolution weather stations in 3 nursery production regions of TX and NC to document EPM activity in different climate regions throughout each state. Two water pan traps, shown to be optimal for this pest, with EPM pheromone will be placed at each site with pheromones replaced per manufacturer recommendations (http://www.agbio-inc.com/). Traps will be collected every two weeks year-round with help from extension agents and cooperating nurseries to count EPM adults.Statistical Analyses: We will use the methodology from Vafaie et al. (2020) to collect high resolution weather station data and calculate cumulative degree days above the lower temperature threshold for EPM of 10.04ºCfrom a biofix date of January 1stfor each sampling year and location using degreedays.net. We will develop a predictive phenological model based on trap catches and climate data and evaluate model performance as described by Damos and Savopoulou-Soultani (2010).Efforts & Evaluation: Training and results from this objective will be provided via in-person programs, webinars and YouTube video(s). We will evaluate the impact of this objective through a post retrospective survey of attendants to measure perceived increase knowledge of EPM life history, biology, and effective monitoring.Objective 2. Determine EPM preference for, and damage to, nursery crop species and cultivars common to NC, TX, and throughout the southern region.Methods:In years 1 and 2 we will visit 3 nurseries in each state three separate times during the growing season (late spring, summer, and fall). At each nursery we will inspect the foliage and surface of the media for EPM eggs, larvae, and webbing. We will also tip each plant from its pot to inspect the surface of the root ball. We will also rate EPM damage as percent of plant canopy affected (leaf damage, stunting, wilting), presence/absence of stem girdling, and assign a marketability rating using a <10% damage thresholdfor the most marketable plants (rating of 1), 10-25% as potentially marketable (rating 2), or unmarketable (3). We will also record irrigation type (e.g., overhead hand, overhead sprinkler, drip), fertilizer type and rate, insecticide regimen, and the wholesale and market value for each commodity inspected, as reported by the grower. To determine differences in feeding preferences, we will conduct laboratory feeding preference assays in TX. We will select 3 cultivars each of 8 woody plant species and 5 herbaceous species to examine EPM preference and potential as hosts. To be sure our work has regional importance we will focus on species and cultivars that are most common and economically important throughout the south based on the southern nursery Crop Profile and Pest Management Strategic Plans, and demonstrated susceptibility from field monitoring in objective 1.For each species we will place a leaf from each of three cultivars in a petri dish with moist filter paper and 5 EPM larvae. This will be replicated 20 times for each species. We will inspect each dish after 1, 4, 8, and 24 hours to record the total percent of leaves consumed (species total) and the percent of each cultivar consumed to determine if some susceptible species have less susceptible cultivars.Statistical Analyses:We will determine if there are differences in observed frequencies of EPM infestation in cultivars or crops being scouted compared to the null hypothesis that there are no differences between crops or cultivars using a chi-square test. We will also determine if the frequency of EPM increases over the season on specific crops over the duration of the season using a generalized linear mixed model with frequency of EPM as the response variable, month as the fixed factor, and crop, cultivar, and location as the random effects. We will determine if larval abundance differs by crop species or cultivar or location within and between states using ANOVA. To determine the susceptibility of host crops to EPM larvae, we will use an ANOVA with crop species or cultivar as the fixed effect and percent of leaf surface consumed.Efforts & Evaluation: Training and results from this objective will be provided via in-person programs, and webinars. We will evaluate the impact of this objective through a post retrospective survey of attendants to measure perceived increase knowledge of EPM plant hosts, crop and cultivar preferences.Objective 3. Determine the efficacy of standard and biological insecticides and application strategies for EPM management in commercial production;Methods: The most recent report of insecticide efficacy for managing EPM, prior to Frank and Nagle (submitted), described experiments from 2012-2015 (Bethke et al. 2017). We will conduct replicated experiments under commercial growing conditions to test the efficacy of relatively new insecticides. We will conduct two efficacy experiments (one in Texas and one in North Carolina) with 8 treatments (9 different insecticides, rates, or application procedure) and 6 replicates each. We will also include two treatments per location composed of biological insecticides and entomopathogenic nematodes.Plants will be infested from our colony with 12 larvae each prior to experiments or we will use naturally infested plants when they are available from cooperating growers. Live larvae and pupae will be counted by destructively sampling 3 replicate plants in each treatment 7 and 14 days after treatment.We will also record plant aesthetic score rating (as in objective 3 above) 14 days after treatment application prior to destructive sampling.Statistical Analyses:We will compare survival of EPM within each DAT, the total number of pupae and aesthetic score at the final DAT between the different insecticidal treatments using an ANOVA with a Tukey's multiple comparison to determine differences between means.Efforts & Evaluation: Training and results from this objective will be provided via in-person programs, and webinars. We will evaluate the impact of this objective through a post retrospective survey of attendants to measure perceived increase knowledge of EPM management and potential decrease in crop loss due to EPM.