Toxicity and Persistence of Surface Applied and Soil Incorporated Insecticides Against Diaprepes abbreviatus Larvae12

Abstract

Laboratory bioassays determined that granular carbofuran, CGA-I2223 ( O -[5-chloro-1-(1-methylethyl)-1 H -1,2,4-triazol-3-yl] O, O -diethyl phosphorothioate), Dowco-275 ( O, O -diethyl O -(6-fluoro-2-pyridyl) phosphorothioate, and ethoprop applied to the soil surface were efficacious against invasion by Diaprepes abbreviatus (L.) neonate larvae one mo posttreatment. Persistence appeared greater in dense soil media. In greenhouse and field tests, larval invasion was prevented by 2 drenches, 12 wk apart, of 0.4 g AI/liter ethoprop. Monthly aldicarb 10G applications did not prevent soil invasion. Aldicarb and ethoprop applications failed to eradicate established larval populations. Additional tests indicated 0.3 g AI/liter drenches of carbofuran or CGA-12223 prevented larval invasion, while concentrations of 1.2 g AI/liter significantly reduced levels of established infestations but were not eradicative. Soil incorporated granular CGA-12223, chlorpyrifos, or ethoprop was ineffective in prevention of larval establishment in soils weathered for 3 mo.