Integrated Management Strategies for Methyl Bromide Replacement in Golf Course Construction and Turfgrass Sod Production

Non-Technical Summary: Methyl bromide (MB) has been the predominant broad-spectrum soil fumigant for controlling pests prior to turfgrass installation on golf courses, sports fields, and sod farms. Pest problems controlled with MB include weeds, diseases and plant parasitic nematodes, however, MB fumigation is primarily used to eliminate weeds and to insure genetic purity of turfgrasses. In the U.S., MB is used on newly constructed and reconstructed golf course greens, and sometimes on tees and fairways. There are approximately 16,000 golf courses across the U.S., serving over 26 million golfers, who play 520 million rounds of golf annually on an estimated 728,000 ha. MB is used on approximately 0.02 percent of the total golf course area in any single year. Fumigation of golf course greens, tees, and fairways is relatively infrequent, so MB is used on an individual golf course perhaps every 15 to 20 years. The identification of best management practices to reduce MB use when an alternative fumigant is used in the golf industry could result in a significant reduction in the CUE request of 63,848 kg MB. This project will aid golf course managers in warm-season climates to transition from methyl bromide (MB) based fumigation strategies to integrated chemical and non-chemical alternatives thereby reducing dependence on MB and the critical use exemption process. This will be accomplished through a multi-faceted approach aimed at identifying best management practices to reduce MB use on turfgrass fumigated sites.<P> Approach: Obj. 1: Research will be conducted on sand:peat putting green. Prior to fumigation, the plot area will be sprayed with glyphosate to kill existing annual weed species and to provide some initial suppression of existing bermudagrass. Plot area will be stripped of existing vegetation and tilled to prepare the soil for sheet steaming/fumigation. Indicator weed species will be incorporated into the soil prior to treatment to determine the effectiveness of the fumigation treatments for preventing weed seed germination. Treatments include sheet steaming + potassium hydroxide; dazomet; sheet steaming + potassium hydroxide + dazomet; iodomethane; methyl bromide; and, 6) a nontreated control. All treatments will be applied using industry standard practices. Soil temperature will be monitored in selected plots using data loggers. Soil samples will be collected after treatment and placed in trays. Lettuce seed will be planted in each tray to serve as a bioassay to test for the presence of residual fumigants. The trays will be placed in a greenhouse and kept moist to allow weed seed and lettuce germination. Weed and lettuce emergence will be evaluated after sampling. Obj. 2: Economic analysis will consider producer costs for alternative production practices, marketability of turfgrass products, and impact to golf courses. Costs and returns to producers will be evaluated using a pro forma budgeting approach. Total annual income will be estimated from yield data and regional average market prices. Production costs will be estimated based on quantities and prices of inputs developed from consensus opinion of producers, researchers and industry experts. Costs will be tracked for a cropping cycle, with quantities and prices of material inputs for production taken from purchase records, and data collection forms developed for field personnel to record work time, so that production related labor can be distinguished from management and research activity. Budgeted costs will be validated against actual costs reported by cooperating commercial growers. Turfgrass that is produced with or without use of MB, may differ in quality characteristics due to varying degrees of weed, insect, and disease control. Marketability and consumer acceptance of turfgrass will be evaluated through market survey research. Obj. 3: An outreach program will be conducted to communicate results to golf course superintendents. This will be accomplished through written and electronic media including extension fact sheets, CD-ROMs, and a website devoted to MB alternatives for golf course managers. Presentations will be made at grower conferences and demonstration plots will be established in conjunction with grower field days. Outputs, or the direct products of the outreach program activities will be measured against outreach program outcomes to assess the impact this research has on golf course managers. This will be accomplished through a series of pre- and post-event surveys developed in cooperation with the Program Dev. and Eval. Center at UF/IFAS. The expected outcomes from this work should easily be verified from grower technology/practice adoption surveys.