Digestive α-amylase inhibition negatively affects biological fitness of the Indian meal moth, Plodia interpunctella (Hub.) (Lep: Pyralidae)

The Indian meal moth, Plodia interpunctella, is a cosmopolitan pest of many different stored products. Pesticides have been relied on as the main action against stored product pests including P. interpunctella, however resistance of pests to many insecticides, and possible side effects of chemical applications have led us to search for safe and more specific alternative control measures such as suppression of digestive enzymes using specific inhibitors. In the present study, we investigated the effect of the amylase inhibitor, acarbose, on the fitness of P. interpunctella to gain a better understanding of the effect of enzyme inhibitors on physiology of digestion and biological characteristics. The results showed a dose-dependent inhibitory effect of acarbose on digestive α-amylase activity in both in vitro and in vivo assays. The zymogram experiments revealed inhibition of at least one and two bands of the enzyme activity in low and high inhibitor concentrations, respectively. As the result of amylase inhibition, significant effects on weight, size of head capsule and length of larvae, larval mortality, pupal weight, adult longevity and fecundity was observed. In general, the amylase inhibitor can interfere in the function of carbohydrate digestion in the midgut, thus affecting many biological parameters of P. interpunctella, and may be an efficient tool for including in integrated pest control programs.