Toxicity, repellency and development inhibition of several essential oils against storage pest Callosobruchus maculatus (bruchidae: coleoptera)

Abstract

Shelf life is considered as an important factor for all agricultural products. Type of different chemicals used as a control measure in storage plays an important role especially when crops and their products are transferred from the farm to storage houses. Previous studies explained that essential oils can be potential insecticides if used according to specifications or in right amount. According to the findings of preliminary studies most entomologists have noted and advocated for the use of essential oils as a potential alternative insecticide to control and manage insect pests in stored and warehouses. The main aim of the present study was that to evaluate the effectiveness of different essential oils including lemon (Citrus limon), citronella (Cymbopogon nardus), ginger (Zingiber officinale), cardamom (Elettaria cardamomum) and cinnamom (Cinnamomum zeylanicum) at 5%, 10%, 20%, and 30% against bean beetle Callosobruchus maculatus under laboratory conditions and their toxicity, repellency and development inhibition effects were noted. Research was carried out at Laboratory of Entomology (SEAMEO BIOTROP), Bogor, Indonesia. The results of study revealed that all the tested essential oils showed better results for development inhibition, mortality and repellency as well. Among the tested essential oils C. nardus was the most toxic to the adults of C. maculatus with the higher mortality after short time period exposure of 24 hours with the minimum concentration of 5% while after 96 hours of exposure with maximum concentration of 30% showed high mortality while other concentrations 10% and 20% showed moderate mortality followed by Z. officinale where it has caused lower percent population reduction at lowest concentration rate while at highest concentration with maximum exposure time showed maximum mortality. Other concentrations at moderate dose rate exhibited moderate population reduction percentage. Minimum population reduction was caused by E. cardamomum where at lowest rate with minimum exposure time showed minimum mortality while at maximum concentration and with maximum exposure tome showed moderate mortality among the tested essential oils at same concentrations. In development inhibition case E. cardamomum results were maximum at all the given concentrations with 100% development inhibition followed by Z. officinale where it has caused higher development inhibition and maximum malformations for different life stages as well. C. limon and C. zeylanicum showed moderate results for development inhibition. Minimum results of development inhibition have been recorded in E. cardamomum. For repellency experiment maximum repellency was showed by C. nardus followed by Z. officinale. C. limon and C.zeylanicum exhibited moderate percent of repellency while E. cardamomum showed minimum results of percent repellency. Overall it is concluded that all the tested essential oils have better effects against storage pest C. maculatus and in future can be used as reliable and effective control measure which can suppress and control C. maculatus in different ways.