Prediction of spray drift using insecticide tracers and two types of collector
Abstract Two insecticides, carbaryl and chlorpyrifos, were evaluated at low concentrations as tracers to predict the behaviour of spray clouds of malathion at field strength. Aerial sprays were produced from a Cessna Ag Husky equipped with a dual liquid dispersal system, spraying simultaneously. Spray drift was measured at 90 or 30 m downwind using 1.6 mm polyester cord and 0.6 mm monofilament line suspended from a helium‐filled blimp tethered 15.25 m above ground level. Recoveries of malathion averaged 87.3% and 85.2% of the amount predicted from the tracers on the monofilament and polyester, respectively. The coefficients of variation for 12 flights were 50.9% for the monofilament line, and 17.4% for the polyester cord.