ASSESSMENT OF FIELD HAZARDS TO BIRDS FROM METHIOCARB APPLICATIONS TO FRUIT CROPS

Methiocarb, a broad-spectrum carbamate insecticide, has shown efficacy in repelling birds from a variety of crops, especially fruit. To eval uate the hazards posed to wildlife, we reviewed laboratory studies of methiocarb toxicity and repellency to birds and mammals and field stud ies of methiocarb treatments to fruit and sweet com. Calculations reve aled that birds encountering typical maximum residue levels found in t reated crops would have to eat extremely large amounts of treated food to die and would in almost all cases be repelled or immobilized long before a lethal dose could be ingested. Results from feeding tests in laboratories support these calculations, as do the findings from 33 fi eld studies in 28 locations. In spite of extensive searches and observ ations, only 14 dead birds were found in treated fields. Based on esti mates from 26 studies, treated plantings averaged 15% loss of fruit to birds compared with 36% for nearby untreated plantings. We conclude t hat methiocarb, applied to fruit crops at 1.7 kg a.i. ha-1, will not a dversely affect birds.