Recipient Organization
MICHIGAN STATE UNIV
(N/A)
EAST LANSING,MI 48824
Performing Department
Plant, Soil and Microbial Science
Non Technical Summary
The game of golf transcends all ages and genders. It is gaining popularity among females even though it has traditionally attracted predominantly males. It is a form of exercise for those who choose to walk rather than use a golf cart. Dollar spot is the most important disease in the northern United States. My lab has been conducting several multi-year studies to determine methods to reduce fungicide use as well as to lower fungicide rates of application in order to reduce their impact on the environment. In the cool season turfgrass growing region of the United States, dollar spot, caused by the fungal pathogen Sclerotinia homoeocarpa, is the most economically important disease on golf courses. The disease can occur from April through October. Multiple fungicide applications throughout the season are required to manage this disease. Management strategies are needed to reduce the environmental impact of managing dollar spot by reducing the number of pounds of fungicide applied to the ground. This would help to reduce the potential for polluting soil and ground water. Golf course superintendents throughout the world would benefit from the findings of this research if the results support our hypotheses. Studies at Michigan State University have shown that the cultural practice of rolling greens three to five times a week significantly reduced the amount of dollar spot. Whereas the original intent of the research was geared towards increasing green speed, a side benefit was the suppression of dollar spot and reducing the need for fungicide applications (15). Golf courses in cool season turfgrass growing regions have greens, tees and fairways that are primarily seeded to creeping bentgrass. Most of the creeping bentgrass cultivars currently being used are susceptible to many fungal diseases including dollar spot. Michigan State University, in conjunction with the Seed Research of Oregon Company, developed a cultivar of creeping bentgrass called Flagstick that is highly resistant to dollar spot. Converting golf course greens, tees and fairways to Flagstick would greatly reduce the need for fungicides to control dollar spot. However, it is difficult to maintain pure stands of creeping bentgrass as they are usually invaded with Poa annua over time. Poa annua, like most of the creeping bentgrass cultivars, is also susceptible to dollar spot. Furthermore, not all golf courses will immediately convert to Flagstick just because it is resistant to dollar spot. Most golf course greens, tees and fairways will remain combination stands of dollar spot susceptible creeping bentgrass cultivars and Poa annua. This is why it is important to determine if rolling, in combination with reduced rate fungicide applications, can reduce fungicide inputs in mixed stands of dollar spot susceptible creeping bentgrass cultivars and Poa annua golf course turfs.Boscalid is a very effective fungicide for the control of dollar spot. It often gives up to 3 weeks control of this disease with a single application. A one drawback to the use of boscalid is a 5 to 7 day delay before the product becomes active in the plant to provide control of dollar spot. It is recommended that boscalid applications be applied with a chlorothalonil fungicide to protect the turf from dollar spot until the boscalid becomes active. This, of course, puts more fungicide load into the environment and increases the potential for pollution. It is hoped that by incorporating rolling in combination with lower rates of boscalid, the need for chlorothalonil applications in conjunction with boscalid will be eliminated. It is also hoped that rolling will allow for the use of lower rates of boscalid while still providing effective control of dollar spot.One current project encompasses the use of an integrated management approach for dollar spot reduction by combining the use of cultural, genetic, and chemical practices. It will continue to be conducted at the Hancock Turfgrass Research Center on the campus of Michigan State University in East Lansing, MI. The goal of this plant pest management strategy is to ultimately reduce environmental inputs. In the research trial, two cultivars of creeping bentgrass including a commonly used dollar spot-susceptible cultivar, Penn A1, and the recently released dollar spot-resistant cultivar, Flagstick, will be compared. For each cultivar, lightweight rolling conducted once or twice daily for five days weekly combined with reduced rate fungicide (boscalid) applications at 25% of the label rate will be evaluated for dollar spot incidence, turfgrass quality and playability as measured by greens speed.A primary goal of the United States Environmental Protection Agency (EPA) is "to ensure that all Americans are protected from significant risks to human health and the environment where they live, learn, and work" (16). Specifically, golf courses are regulated in such areas as fertilizer use, pesticide storage and use, and wetland preservation. The objective of this second research project is to reduce human exposure risk from fungicides and the environmental risk from nitrogen/phosphorus fertilizer applications to golf courses and other highly maintained turfgrass areas, while meeting or exceeding current industry standards of turfgrass quality and disease management. Addition of a small amount of an MSU-developed, patent-pending adjuvant/biostimulant to the spray tank allows for a reduction of 50% or more in the label application rates for fungicides and fertilizers, without a loss of efficacy (5). Continued testing of the efficacy of the formulation and component ratio testing is needed. The focus will be on the management of three important golf course diseases (snow mold, anthracnose, and dollar spot) with tank-mixes of the MSU adjuvant and reduced rates of relevant fungicides.In addition to the previously described disease research projects, a need has been identified to investigate nematode problems in turf. A recent trend shows an increase in nematode-related issues in turf on golf courses. A third project involves studies to evaluate the extent of this problem and to identify which of the new nematicides are most effective in managing nematodes in the northern hemisphere. Whereas these nematicides have been tested on nematodes common to the southern United States, there has been no research conducted with them in the northern United States.
Animal Health Component
90%
Research Effort Categories
Basic
(N/A)
Applied
90%
Developmental
10%
Goals / Objectives
Test and establish parameters for reduced fungicide management of creeping bentgrass putting greens by utilizing a disease-resistant bentgrass cultivar, reduced fungicide rates, and optimizing lightweight rolling practices.Determine whether acceptable levels of disease, turfgrass quality, and playability are obtainable without the use of fungicide or reduced rates of fungicide through data collection and analysis.Determine whether bacterial population abundance is affected by irrigation programming or host susceptibility to dollar spot.Evaluate the effect of irrigation frequency and timing on soil moisture in the upper soil profile and on dollar spot incidence in fairway height turfgrass.Test the efficacy of a spray additive that can reduce human exposure risk from fungicides and the environmental risk from nitrogen/phosphorus fertilizer applications to golf courses and other highly maintained turfgrass areas, while meeting or exceeding current industry standards of turfgrass quality.Monitor already established snow mold disease adjuvant/fungicide fairway studies using MSU adjuvant/biostimulants in combination with reduced fungicide rates.Continue dollar spot and anthracnose disease adjuvant/fungicide studies using commercial canola oil (Persist UltraTM) and pigment (EnvyTM), produced by Precision Labs, Inc., in combination with MSU's adjuvant to modify previous studies showing reduced fungicide application rates. Investigate the impacts of the nematicides Divanem (abamectin), Indemnify (fluopyram), and Nimitz (fluensulfone) on populations of nematodes, other soil invertebrates, and selected prokaryotes.Determine if nematode species population changes over time by sampling and analyzing soil from greens of different ages.
Project Methods
Rolling resistance study: A large (~5,800 ft2) study site was established at the Hancock Turfgrass Research Center on campus in a randomized complete block design using three replicates of two different creeping bentgrass cultivars: 'Penn-A1' (dollar spot susceptible) and 'Flagstick' (dollar spot resistant). Within each cultivar plot, seven treatments will be randomly located and treated as follows:Rolling once per day (1x)Rolling twice per day (2x)Rolling once per day (1x) with reduced fungicide application (1/4x rate)Rolling once per day (2x) with reduced fungicide application (1/4x rate)No rolling with reduced fungicide application (1/4x rate)No rolling with standard fungicide application (full label rate)Untreated controlRolling treatments of 1x and 2x per day will be implemented five days per week throughout the growing season (mid-May - September). These treatments have been selected based on research studies showing the impacts of daily rolling on dollar spot incidence (7, 15). A rolling treatment will consist of rolling across the plot in one direction, and back across the plot in the opposite direction. The roller will be provided by Smithco (Wayne, PA), and will be representative of a commonly used model on golf courses around the world. Weighing around 800 lbs, the roller will be carefully maneuvered via its steering mechanism through the untreated alleyways between plots while staging rolling treatments. This will ensure uniform rolling coverage and minimize misapplication on plots. A standard full label rate fungicide treatment will be applied as a positive control and will consist of 28-day interval sprays of the fungicide boscalid (Emerald, BASF) using the maximum labeled rate. Other fungicide treatments will be applied at 25% of the maximum labeled rate on a 28-day interval, representing reduced fungicide usage. These reduced rate applications will be made as standalone treatments as well as in combination with daily rolling (both 1x and 2x rolling frequencies). Assessments will be made throughout the growing season. Disease will be rated when present on a whole-plot percent basis (0-100) using visual assessment which an industry accepted method. Dollar spot, as well as other prevalent diseases, will be rated on all plots throughout the duration of the dollar spot season (May - October). Visual quality ratings will be assessed by considering turfgrass density, uniformity, color, and overall appearance and will assessed on a 1-9 scale. Chlorophyll (color) ratings will be collected using a FieldScout TCM 500 NDVI Turf Color Meter which measures reflected light from approximately a 7.5 cm diameter section of turfgrass in the red (660nm) and near infrared (850nm) spectral bands. Data analysis will be performed in SAS.Irrigation timing microbial Populations: The proposed project focuses on irrigation applications with different timing and frequency and their impact on microbial populations in the upper inch of soil, which may help explain the reduction of dollar spot resulting from these different irrigation regimes.Evaluate the effect of irrigation frequency and timing on soil moisture in the thatch and upper soil profile and on dollar spot incidence in fairway height turfgrass: This dollar spot study will be conducted on previously established individual plots of 'Declaration', 'Flagstick' and 'L-93' cultivars of creeping bentgrass fairway turf maintained at 0.5" height of cut. Three irrigation regimes will be randomly assigned to each of three 36' x 36' irrigation plots. Irrigation averaging approximately 0.1" (historically approximately 80% PET) will be applied daily at either (a) 0500 h or (b) 2200 h, or (c) 0.3-0.4" will be applied twice weekly at 2200 h. Within each irrigation whole plot are 3 cultivar subplots measuring 9' x 12'. All plots will be fertilized at 0.5 lb. nitrogen per 1000 ft2/month. Soil moisture will be monitored using a Spectrum Technologies TDR 300 with 1.5" probes twice weekly. PET will be monitored using the MAWN website, averaged on a weekly basis, and 80% of that amount will be applied per irrigation treatment, i.e. the total amount divided by 7 and applied daily or divided by 2 and applied twice weekly. Further data collection will include measurements of dollar spot incidence, which will be rated by visually estimating the percent of the plot area infected with disease, a standard method used in small plot, high maintenance turfgrass research. In addition, turfgrass quality ratings will be taken using a 1-9 scale, and chlorophyll (color) ratings will be collected with a FieldScout TCM 500 NDVI Turf Color Meter. Facilities to be used in the research include creeping bentgrass fairway plots in nine 40 ft x 40 ft irrigation blocks located at the Hancock Turfgrass Research Center on the MSU campus. Equipment to measure soil moisture, temperature and humidity are currently owned by the Vargas lab.Fungicide and fertility efficacy tests with MSU patented adjuvant to reduce fungicide and fertility inputs: The MSU adjuvant will be applied with ½ and ¼ label fungicide rates and compared to standard label recommended rates for important turfgrass diseases like dollar spot, anthracnose and the snow molds. The dollar spot and anthracnose plots will be evaluated on a weekly basis to determine the efficacy of the reduced rate fungicide application in combination with the MSU adjuvant compared to label rates. The snow mold treatments will be evaluated following snow melt in the spring of the year. Clippings will be collected for each treatment to determine whether the MSU adjuvant can reduce fertilizers inputs. Visual quality ratings will also be taken weekly to investigate whether the quality of the turfgrass has improved.Nematode populations and control studies: We will conduct research at the MSU Hancock Turfgrass Research Center as well as selected golf courses. Replicated fields trials will be established at the Turfgrass Facility consisting of five replications per treatment. Plots will be left untreated or be treated with Divanem, Indemnify, or Nimitz. Plots will be sampled and soil analyzed for nematodes as well as other microscopic, soil invertebrates (oligochaetes, rotifers and tardigrades) five times during the golf season at 45-day intervals for 180 days. Sampling will commence the day of the first application of nematicide in May. Nematodes and other microscopic animals will be enumerated in every plot. Soil samples collected will be divided into two portions, one containing the top 2" of soil and the second containing soil from a 2-6" depth. A separate analysis will be conducted for each portion. In preliminary sampling done in the fall of 2017, stunt nematodes were recovered from soil in the top two inches of the greens tested but none were detected from 2 - 6 inches. Ring and spiral nematodes were found in roughly equal numbers in the top two inches and at the deeper depths. Most biological activity in turf is associated with the root zone and thatch layer, so differences might be more drastic following applications with nematicides. Nematodes will be extracted from 100 cm3 of soil using centrifugation/flotation (9). Plant parasitic as well as beneficial nematodes will be counted. The centrifugation/flotation method also recovers other microorganisms, those small enough to pass through a sieve with openings of 1.2 mm but large enough to be collected on another with openings of 38 um. Microscopic earthworms (oligochaetes), rotifers and tardigrades are all beneficial organisms that may also contribute to the health of the soil and may be noted upon sample analysis.