Insecticidal Activities of Essential Oil from Piper betle Linn. Against Storage Insect Pests

摘要

The insecticidal activity of essential oil extracted from the leaves of Piper betle (Linn.) was evaluated against the bean weevil (Callosobruchus maculatus F.), the corn weevil (Sitophilus zeamais Motchulsky) and the lesser grain borer (Rhizopertha dominica F.) using aged grain assay. The efficacy of treatments was assessed by determining the acute toxicity on adult insects and the extent of preventing or suppressing the production of progenies. The volatile oil in 30% dust formulation exhibited toxicity against adult C. maculatus, S. zeamais and R. dominica at varying application rates such as 0.2 g/100 g, 1.75 g/100 g and 2.0 g/100 g, respectively. Survival of adult C. maculatus was prevented up to 6 mo by 52% while the treatment allowed 6 mo protection of corn against S. zeamais and R. dominica. Although eggs were visible in the treated mungbean, the treatment prevented them from further development. Meanwhile, the absence of eggs of both S. zeamais and R. dominica was prominent in the treated corn. The treatments were able to inhibit entirely the emergence of progenies. No living progenies were observed in treated samples until 6 mo while progenies were abundant in two control samples, check and untreated. The results, therefore, suggest thatthe essential oil from P. betle leaves is a promising grain protectant.