The purpose of this research is to assist growers in the adoption of economically effective alternatives to methyl bromide for the control of weeds, diseases, and nematodes. <ol> <LI>Implement replicated large acreage methyl bromide alternative trials with five growers on over 60 acres in five counties for the management of weeds, diseases, and nematodes. <LI>Determine the most effective and economical methyl bromide alternative fumigant rates when applied under various types of mulch. <LI>Establish plant back intervals required when alternative fumigants are applied under various mulches.<LI>Investigate the impact of multiple-season adoption of methyl bromide alternatives in terms of pest species composition, including weeds, diseases, and nematodes.<LI>Evaluate the mechanisms that allow purple nutsedge to persist and reproduce under various mulch types.<LI>Compare the economic validity of each methyl bromide alternative system for all trials conducted in objectives 1-4 for potential adoption by southeastern vegetable producers. <LI>Distribute results on the adoption of methyl bromide alternatives to growers and other interested parties.
Non-Technical Summary: Vegetables produced on plasticulture in Georgia account for a farm gate value of over $340 million dollars. Methyl bromide controls weeds, diseases, and nematodes in these crops. Currently, methyl bromide is available in Georgia through our Critical Use Exemption efforts. Acceptable methyl bromide-alternative systems have not been adopted by vegetable growers in the Southeast because these alternatives lack weed control, especially for nutsedges (Cyperus spp.). A recent survey by Georgia Extension Agents noted that moderate to severe nutsedge infestations are present on up to 66% of our acreage, clearly emphasizing that any acceptable methyl bromide-alternative system must address nutsedge control. Our research has shown there are three potential methyl bromide alternatives that have been successful for the management of weeds including nutsedge, diseases, and nematodes in small-plot research. However, these efforts must be duplicated in large acreage replicated trials with fumigant systems being applied by growers with our assistance. While a single fumigant was previously the cornerstone for pest control in vegetable crops, significant research efforts have shown that an integrated management system that utilizes cultural practices, alternative soil fumigants, various mulches, and herbicides will be required to replace methyl bromide. These systems are being perfected in small-plot research but must be implemented in grower fields. <P> Approach: This research will be conducted throughout Georgia including a minimum of nine (some growers will conduct two trials) on-farm replicated trials located in Colquitt, Cook, Echols, Lowndes, and Tift counties as well as three research facilities including the Ponder Research Farm (University of Georgia), the Jones Research Farm (USDA-ARS), and the Tifton Vegetable Park (Research and Demonstration, University of Georgia). Research trials will be conducted on soils with 88 to 96% sand, which represents vegetable producing areas throughout Georgia and the southeast coastal plain. Climate affords multiple growing seasons each year in Georgia, therefore trials will be conducted for both spring and autumn crops in each year. Fertilization, cultivar selection, insecticides, fungicides as well as all other production aspects will be implemented by growers in the on-farm trials and will follow recommendations by the University of Georgia Cooperative Extension Service. These trials will focus on fruiting vegetables and cucurbits; however, successful pre-plant soil-applied fumigant alternatives will be applicable in all vegetable crops that previously used methyl bromide.