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Insecticide Choice for Alfalfa May Protect Water Quality

The Issue

Some insecticides used for controlling Egyptian alfalfa weevil have been detected in California's surface waters. Many are of concern due to their impact on water quality and toxicity to some aquatic life.

What Has ANR Done?

UCCE farm advisors and specialists teamed up to determine how organophosphate insecides move offsite from alfalfa fields, and to find alternative pesticides that do not impair water quality in irrigation runoff. In a three-year project, they demonstrated that using pyrethroid pesticides rather than the more common organophosphates is more effective for controlling Egyptian alfalfa weevil and also reduces the amount of pesticide that could run off the field into natural waterways. This project involved working directly with 30 farmers in the northern Sacramento Valley. UCCE's link with farmers helped this project succeed because we worked together for a solution on water quality problems.

The Payoff

Use of chlorpyrifos on alfalfa down 60% in Yolo and Solano counties

As a result of this project, annual use of the organophosphate chlorpyrifos in alfalfa decreased by 50% in Yolo County (14,000 lbs to 7,000 lbs) and by 75% in Solano County (12,000 lbs to 3,000 lbs). Reduced organophosphate use in alfalfa will help improve water quality in areas where there is irrigation runoff from alfalfa fields and organophosphates are found in surface waters.


Supporting Unit: Yolo County

Rachael Long
Farm Advisor, Yolo County
(530) 666-8734