Effects of radiofrequency on the development and performance of Callosobruchus chinensis (Coleoptera: Chrysomelidae: Bruchinae) on three different leguminous seeds

Abstract

Callosobruchus chinensis (L.) (Coleoptera: Chrysomelidae) is a common insect pest of stored legume seeds around the world. Since chemical insecticides and fumigation can have adverse effects on human health and environment, the development of a non-chemical method to replace chemical insecticides is urgently needed for the control of stored products pests. In this study, we investigated the oviposition preference, development, and adult performances of C. chinensis at five radiofrequency levels of 0 (control without frequency), 5, 10, 20, and 30kHz on three leguminous seeds: azuki bean, cowpea, and mung bean. In addition, the effects were also studied in three successive generations (parent, F1- and F2-generations) of C. chinensis. We found that radiofrequency application had significant effects on the life history variables of C. chinensis. Radiofrequency exposures on C. chinensis not only affected developmental period, adult longevity and adult weight, but also negatively affected the fecundity of subsequent generations. The total developmental period from egg to adult emergence was longer and adult longevity was shorter in the radiofrequency treatments than in the untreated control. Reduced radiofrequency levels coincided with increased sexual development of adults. The lowest rate of adult emergence and the shortest adult longevity both occurred at 5kHz. The outcomes of this study are discussed in terms of targeting susceptibilities to radiofrequency in storage and semi-field conditions as an alternative to chemical treatments.