Alternative Management Strategies for Carrot Rust Fly
The project cooperators will be targeting Washington State’s 7,000 acres of processing carrots (35 percent of the nation’s processed carrots) and 2,600 acres of fresh market (3 percent). They hope to have 25 percent of growers monitor for rust fly, use rotations and cover crops to reduce rust fly and enhance their beneficial populations, and row covers, wherever practical, to eliminate rust fly. They will also work with growers to adjust their planting and harvesting dates to avoid pests. They hope to reduce the use of diazinon by nearly 100 percent. Cover crop experiments are being conducted at the Puyallup (Hairy vetch) and Vancouver (crimson clover) Research and Extension Centers. Partner farms include Terry’s Berries Organic CSA farm in Tacoma, Collenwood Farm in Chimacum (owned by John Gunning), Dungeness Organic Produce in Sequim and Thorney Farm in Woodland.
Project goals and objectives
1. Determine the effect of cover crops and planting date on Carrot Rust Fly populations.
2. Monitor egg, and adult Carrot Rust Fly populations on the experimental plots located at Puyallup and Vancouver WSU experiment stations.
3. There is no historical presence of Carrot Rust Fly on the WSU-Puyallup experiment station; therefore, a first year objective was to establish a population at that location. that location. The cooperators were able to demonstrate that they could increase predatory beetle populations by creating additional habitat with the cover crops but were not able to show that these generalist predators had an impact on CRF populations.
4. Work with three farmers to develop an adult monitoring program using Carrot Rust Fly specific sticky traps in conjunction with the use of row covers to help reduce the need for pesticide applications.
Cooperators established monitoring programs for CRF (Carrot Rust Fly) on four farms, three organic and one conventional. They developed a pest management strategy that incorporates both cover crops and row crops to reduce CRF damage without reducing carrot yields. Interplanting cover crops with a cash crop is quickly becoming an accepted practice for small farmers in western Washington. Due to a lack of native CRF population pressure on the WSU Puyallup experimental plats, they were not able to document the effectiveness of interplanting cover crops for the management of CRF damage but farmers are adopting the practice anyway because of its soil nutrient and environmental benefits. The literature suggests that cover crops should reduce oviposition rates on carrots. The cooperators were able to demonstrate that they could increase predatory beetle populations by creating additional habitat with the cover crops but were not able to show that these generalist predators had an impact on CRF populations.