Effect of temperature on the morbidity and recovery of the Pacific Coast wireworm, Limonius canus, following contact with tefluthrin‐treated wheat seeds

Abstract

AbstractLate instars of the Pacific Coast wireworm, Limonius canus (LeConte) (Coleoptera: Elateridae), were exposed to wheat seeds treated with tefluthrin at 10 g active ingredient/100 kg wheat seed, for 2 min, at 10, 15, 20, and 25 °C. All wireworms were moribund within 20 min of first exposure and recovered fully within 7 h. Morbidity induction time (i) decreased considerably as the temperature (t) was increased from 10 to 15 °C, but did not decrease further when the temperature was increased from 15 to 25 °C. For each temperature, induction time decreased as wireworm weight (w) increased, so that . A strong negative temperature coefficient was observed in wireworm recovery, the time required for recovery (r) after exposure decreasing as both temperature (t) and wireworm weight (w) increased, so that r = 1102.47(w)−0.1848 * e−0.1012t. The temperature at which wireworms contact insecticides in the field may significantly affect the induction and duration of morbidity, and determine whether wireworms will become moribund before they are repelled by tefluthrin. The ability of wireworms to recover from tefluthrin‐induced morbidity may seriously limit the efficacy of this insecticide in reducing wireworm populations in the field.