Persistence and uptake of cloethocarb in a mineral soil and its efficacy against the tuber flea beetle, Epitrix tuberis Gentner

Abstract

Lance 15G (15% cloethocarb) at 2.0 and 4.0 g of ai/lO m of row was applied as an in-furrow band to potatoes (cv. Russet Burbank) a t planting in a silt loam to control the tuber flea beetle, Epitrix tuberis Gentner. Cloethocarb persisted in the soil for more than 64 days, and its disappearance followed first-order kinetics. The calculated rate constants and half-lives were 0.032 d a y 1 and 21.7 days at the low rate and 0.023 day-' and 30.1 days at the high rate. Cloethocarb was translocated readily into potato leaves. The ratio of cloethocarb concentration between the leaves and the treated soil was highest (3.35) in 37-day-old plants and lowest (0.90) in 65-day-old plants. The concentrations accumulated in the leaves were lethal to the adult beetles and effectively suppressed the populations of overwintered adults introduced to treated plants 28-30 days after planting. Almost complete adult mortality occurred within 24 h of beetle release, which resulted in a significant reduction of emergence of the next generation of adults. Control of beetles released onto treated plants 56 and 64 days after planting, however, was less effective.