Adulticidal and Larvicidal Toxicity of Aldicarb when Applied as a Soil Insecticide1

Abstract

Aldicarb applied to the soil killed flies of the cabbage maggot, Hylemya brassicae (Weidemann), standing on the surface or drinking from surface moisture in less than 30 sec, and many other kinds of insects in 1 min or less. When applied below the soil surface, toxicants moved to the surface and residues were toxic for several weeks to several months, depending on the concentration and depth of application. Toxicants appeared to move from the soil surface into the tarsal pulvilli or the labella of the insects via a moisture bridge. Addition of excess water to the surface of the soil caused downward leaching, but toxicants again moved upward as moisture moved to the surface and evaporated. The adulticidal effect was negligible after treated soil became air dry but returned to high potency immediately after the surface was moistened. Toxicants of aldicarb were absorbed by rutabagas grown in treated soil and became more highly concentrated in the pulp than in the peel.