Abstract

Petroleum ether, acetone and water extracts, and fresh seed powder of Milletia ferruginea (Hochst) Baker (Leguminaceae) were evaluated as grain protectant against bean bruchid, Zabrotes subfasciatus (Boheman) in the laboratory at an ambient temperature of 28±1°C and 70% RH in a 12 h light: dark regime at the concentrations of 1, 2 and 3 ml in the case of extracts and at the rates of 5, 10 and 15 w/w in the case of seed powder. Adult mortality, F₁ progeny emergence, oviposition inhibition, insect damage and viability index of haricot bean seeds were the parameters measured. The results obtained showed that water and acetone extracts of M. ferruginea gave 100% mortality of the adult Z. subfasciatus 24 h after treatment application at the rates of 2 and 3 ml. M. ferruginea powder provided good protection of haricot bean seeds by reducing Z. subfasciatus oviposition rate, F₁ progeny emergence and seed infestation. The seed powder treatment did not show any adverse effects on the germination capacity of haricot bean seeds. This study revealed that M. ferruginea can be used as a botanical insecticide to protect haricot bean seeds against Z. subfasciatus in storage.

Key words: Botanicals, Milletia ferruginea, Zabrotes subfasciatus, toxicity, storage pest.