Time to End County Insecticide Spraying Programs Targeting Native Insects

Beginning in 2000 and for several years since then including 2013 and 2014, Fairfax County, Virginia has sprayed insecticide by helicopter and truck over thousands of acres in the county targeting a native moth caterpillar called the fall cankerworm, also affectionately referred to as the “inchworm.” As a native, the fall cankerworm has evolved over the millennia with our trees and wildlife. The insecticide applied is deadly to all exposed butterfly and moth caterpillars, not just the native target.  The County estimates that 80 – 90% of fall cankerworm populations are eliminated in the spray areas, but does not measure the impacts on other butterfly and moth caterpillars. Fall cankerworm caterpillars are an especially important food source to migrating and breeding birds. Insecticide spraying takes place during peak songbird migration from mid-April to mid-May. Birds are also beginning their breeding season at the time of the insecticide spraying. Chickadees feed their young a diet more than half comprised of caterpillars like the fall cankerworm alone. Fall cankerworm caterpillars are an ideal food source for birds because they are smooth, without hair or spines, and lack chemical defenses. Adult moths are food for Eastern screech owls and other wildlife like the Eastern red bat, which is a moth specialist. Prince William County also conducts a broadcast insecticide-spraying program targeting the native fall cankerworm.