Hero Image

Innovative Almond Pest Control Reduces Toxic Pesticide Use and Improves Environment

The Issue

Tree crop growers typically use organo-phosphate (OP) pesticides in the dormant season to control an array of harmful insect pests. However, chemical residues of OP insecticides have been found in California waterways at concentrations harmful to aquatic life in the ecosystem. Apparently, heavy winter rains wash pesticide residues from orchards into nearby streams that drain into the major river systems. As a result of river water testing, state regulations have outlawed or imposed strict limitations on the use of many chemicals. The development of environmentally safe and effective alternatives to toxic chemicals is critical to sustaining both profitable crop production and a healthy environment.

What Has ANR Done?

Field research conducted by UC farm advisors led to the discovery of an effective alternative to toxic dormant pesticides. Using the environmentally compatible insecticide Bacillus thuringiensis (Bt), a novel insect spray program was developed. Bt sprays pose no danger to humans or the environment but are deadly when ingested by worm pests. Well-timed bloom sprays of Bt could replace dormant OP sprays and effectively control the peach twig borer at the worm stage. Bt is a natural and very safe insecticide that is sanctioned for use even in organic farming systems Large-scale on-farm demonstration plots conducted by UC farm advisors throughout the state proved to growers and pest control advisers that this new approach was effective and economical.

The Payoff

River ecosystem improved

Almond orchards, covering 680,000 acres in the Central Valley, were one of the largest users of OP sprays in California. As a result of governmental regulations, dormant applications to almonds of all OPs declined 80 percent from 1992 to 2000. In the void left by the regulatory loss of OPs, the Bt program provided an effective alternative for controlling a major almond pest. California's environment has been the beneficiary. Recent government pesticide testing programs in California waterways now report reduced levels of OPs throughout the state river system representing a substantial reduction in the toxic load on our ecosystem.


Supporting Unit: Colusa County

John Edstrom
UC Farm Advisor
Colusa County
(530) 458-0570