Almond and stone fruit growers reduce OP, increase pyrethroid use in dormant sprays

Growers and pesticide applicators in California are legally required to file pesticide use reports with details about every application to commercial crops. We used the individual applicator records to document a decline in the use of organophosphate pesticides (OP) on almond and stone fruit orchards during the rainy season in California, a time period in which the trees are dormant. The decline is important because dormant applications are a major source of surface water contamination and the Federal Clean Water Act mandates a reduction in movement of OPs into surface water. However, the decline in use of OPs has been accompanied by an increase in use of pyrethroid pesticides, particularly in stone fruit orchards. Additional implementation of “reduced-risk” integrated pest management practices could further reduce use of dormant applications of OPs and pyrethroids on almonds and stone fruit orchards