MAGNET: A Collaboration to Reduce Dependence on Chlorpyrifos Use
The threat of losing chlorpyrifos (Lorsban) under the Food Quality Protection Act coupled with the development of pest resistance has increased the willingness of growers to test and adopt new management strategies for the cabbage root fly, Delia radicum (also known as the cabbage maggot or CM). In the spring of 2001, researchers started “MagNet,” a network of people working together to develop a best management strategy for the cabbage root fly. As part of this effort, the project cooperators will be targeting Clackamas, Marion, Multnomah counties (140 farms with 10,000 acres) plus 40 farmers on 4,000 acres in the Willamette Valley who grow turnips, rutatbaga and radish. Many of these fresh market vegetable farms are in the now highly urbanized area south of Portland. Their goals include persuading at least 10 growers to adopt at least one additional and at least 10 growers to adopt monitoring practices.
Project goals and objectives
The overall objective of the MagNet project is to reduce grower dependence and broad-spectrum pesticide use of Lorsban (chlorpyrifos; organophosphate) to manage cabbage maggots and to expand grower interest in and adoption of a multiple array of IPM tools for CM management.
The project cooperators made significant progress towards developing a wide array of IPM tactics to control cabbage root fly including monitoring methods, degree-day modeling to predict emergence, spatial management (GIS mapping), spring and fall field cultivation methods; enhancement of beneficial organism habitat; placement of row covers; and testing of alternative chemistries and application methods. They documented three to four egg laying periods, fine-tuning types of traps, their placement and correlating the catches for degree-day modeling. This will help growers better time treatments to high risk periods and will reduce the number of chemical treatments. At least four cooperating growers used monitoring information to eliminate spray applications. Lorsban applied only to furrows, Fipronil, Mustang (pyrethrin), Spinosad (bacterial by-product), Warrior (lambda-cyhalothrin) and film-treated seeds all showed promising results. Fall-disking of pupae-infested fields also worked to reduce the emergence of cabbage root fly adults. Now that several management tools have been validated, the cooperators are transferring these tactics to growers and working with them to choose the right combination of tools. Since growers have been involved throughout the project, the transfer should be rapid. The cooperators are completing a “MagNet IPM Tools Guide” and have started holding Tool Transfer Workshops to help growers design a personal toolbox and achieve integration of tools on their farms.