PERSISTENCE OF INSECTICIDES IN A LOBLOLLY PINE SEED ORCHARD FOR CONTROL OF THE LEAFFOOTED PINE SEED BUG, LEPTOGLOSSUS CORCULUS (SAY) (HEMIPTERA: COREIDAE)

Abstract

AbstractHigh volume sprays of azinphosmethyl, chlorpyrifos, fenvalerate, permethrin, and phosmet in various concentrations and formulations were simulated on loblolly pine (Pinus taeda L.) foliage in a pine seed orchard in northern Georgia. Persistence of these insecticides under field conditions was determined by weekly bioassays with adult leaffooted pine seed bugs [Leptoglossus corculus (Say)] and gas–liquid chromatography. Fenvalerate was the most persistent insecticide tested. In the first experiment, 0.2% AI fenvalerate caused virtually 100% seed bug mortality in bioassays through the 4th week after treatment, whereas mortality from azinphosmethyl dropped to ca. 14%. By the 6th week, mortality in the fenvalerate treatment was still 91%, even after 10.5 cm of rain. The permethrin treatments persisted for 2 weeks, then mortality declined below 40% at 3 weeks. In the second experiment, fenvalerate at 0.15% AI and 0.075% AI caused 95 and 90% mortality, respectively, after 3 weeks and 16 cm of rain, and the toxicity of the 0.038% and the 0.019% AI fenvalerate treatments lasted only 2 weeks with 12 cm rain. Permethrin in Ambush® EC at 0.2% AI had initial residues of about 150 ppm and caused ca. 84% mortality for 2 weeks with 12 cm rain. Azinphosmethyl WP at 0.2% AI had initial residues of ca. 104 ppm and persisted for 1 week. Seed bug mortality from phosmet at 0.4% AI diminished quickly after 1 week in the field.