Insecticidal efficacy of two diatomaceous earths from Serbia against the Plodia interpunctella (Lepidoptera: Pyralidae) infestation on maize

Abstract

The evaluation of diatomaceous earths (DEs) against a wide range of major stored-product insect pests highlights their possible importance in integrated pest management protocols, as an environmentally friendly alternative to conventional insecticides. This study was conducted to evaluate the insecticidal efficacy of two DEs from Serbia (DE S-1 and DE S-2, mined in the Kolubara region) and one commercial formulation (Protect-It®) applied at rates of 0.5, 1.0 and 1.5 g/kg, as maize protectants against the infestation of Plodia interpunctella. The total number of P. interpunctella adults that survived the treatment with DEs was recorded and the life history traits (mean developmental duration (MDD), sex ratio, adult longevity and fecundity) were investigated. Although Protect-It® proved 100% effective in protecting maize from P. interpunctella infestation in all three applied rates, both DEs from Serbia also showed significant efficacy. The results indicate that DE S-1 and DE S-2 could effectively suppress P. interpunctella infestation on maize, based on significantly low number of emerged adults, prolonged MDD and shorter adult longevity.

Fecundity was lower in the treatments with DE since only one pair of moths successfully mated and laid 41 eggs. No losses in maize weight were registered in treatment with Protect-It®. In DE S-1 and S-2 treatments, maize weight losses were significantly lower in comparison to the negative control. Diatomaceous earth S-1 applied at a rate of 1.5 g/kg and DE S-2 applied at rates 1.0 and 1.5 g/kg significantly influenced mean developmental duration and longevity of P. interpunctella adults and showed excellent insecticidal potential in this moth control and suppression on maize. The results of this study provide the necessary information about the possibility of preventive application of Serbian DEs, against P. interpunctella infestation.