The Lodi-Woodbridge Winegrape Commission Crush District 11 was created by referendum during the summer of 1991. The commission conducts extensive on-farm research trials and demonstration projects in cooperation with the University of California, the California State University system and local growers. The results have been disseminated through a series of regular grower meetings, seminars and an IPM newsletter sponsored by the commission and widespread coverage in the agriculture and general media. Several pest management practices which could reduce pesticide inputs have been promoted by the commission's IPM Program, and others are being further validated or are being researched for applicability to growers in the area. The research falls into two distinct categories. The first category of research is evaluation of the efficacy of recommended practices and includes economic analysis and the collection of biological data to evaluate performance from the perspectives of vineyard ecology, input use, and profitability. Intensive study of 10 growers over 2 years showed a highly variable level of adoption. The yield response to pest control inputs showed increasing returns up to the level of inputs of $375 per hectare after which returns leveled off. The second category of research is the development of alternative practices through on-farm controlled trials. The results of 3 on-farm trials are reported. A cover crop trial showed a reduction of pests in 1995 but no difference in 1994 between the cover cropped and bare soil blocks. Yellow sticky bands significantly reduced the number of leafhoppers in a trial vineyard, but was not as effective as pesticide treatments. The comparison of four alternative weed management techniques demonstrated that the use of an in-row cultivator is more effective than preemergent herbicides or mulch placed along the vine row in controlling weeds. A visual sprayer was shown to reduce the use of contact herbicide. The on-farm approach to all of the research and the ‘in your own backyard’ nature of the meetings has created the sense of ownership for the growers that has been instrumental in achieving grower support. The public nature of the information provided by the commission and grower members to all winegrape producers implies a recognition among members of their interdependence and the long-term benefits of reducing pesticide use as a group. The recognition of interdependency is crucial for any group trying to form an IPM district.
integrated pest management winegrapes pesticides cover crops sustainable agriculture economics