Toxicity of botanical insecticides on<i>Diaphania hyalinata</i>, their selectivity for the predatory ant<i>Paratrechina</i>sp., and their potential phytotoxicity on pumpkin

Abstract

The use of botanical insecticides could be an alternative efficient pest management in Cucurbitaceae against melonworm Diaphania hyalinata and less harmful to its predator. Few studies jointly assess the efficiency of botanical insecticides, their effects on pest, and their effect on the natural enemy and target crop. Here we examine (1) their impact against the melonworm D. hyalinata, a key pest of Cucurbitaceae, (2) their toxicity to the predatory ant Paratrechina sp., and (3) their phytotoxicity to pumpkin plants. The botanical insecticides citronella oil and eucalyptus oil were highly toxic to D. hyalinata and they exhibited to be less harmful for the predatory ant Paratrechina sp. Andiroba oil, eucalyptus oil, garlic extract, and citronella oil caused feeding inhibition of the D. hyalinata larvae. Eucalyptus oil, andiroba oil, garlic extract, and rotenone inhibited the oviposition of D. hyalinata. None of the insecticides was phytotoxic to pumpkin plants. Eucalyptus oil and citronella oil have induced high mortality and altered the behavior of target pests. In addition, they were selective for the predator Paratrechina sp. and not exhibited phytotoxicity on pumpkin plants. Eucalyptus oil and citronella oil seem the most promising compounds for incorporation into melonworm management programs, because they induced high mortality and altered the behavior of target pests and were selective for the predator Paratrechina sp.