Biodegradation of pesticides in soil: Rapid degradation of isofenphos in a clay loam after a previous treatment

Publisher Website
Google Scholar
Abstract
In May 1983, isofenphos (Amaze® 20G) was applied in a 15 cm wide band at 11.0 g AI per 100 m to clay loam soil contained in duplicate small field plots and it was incorporated into the soil by light raking to simulate application for corn rootworm, Diabrotica spp., control. Soil samples were taken from within the band at intervals over 49 wk and were analyzed for insecticide content. After soil samples were taken from the band in the spring of 1984, the soil was thoroughly mixed and the application, sampling and analyses were repeated. In 1984 isofenphos was much less persistent than in 1983. Laboratory tests with 1984 soil samples taken pretreatment and 3 and 10 wk post‐treatment all showed that isofenphos disappeared significantly faster in previously‐treated soil compared to previously‐untreated control soil, ie. 1–2% vs 55–83% remaining after 7 days, suggesting that soil microorganisms had developed a capacity for rapid isofenphos degradation.