Biology and management of rice weevil, Sitophilus oryzae (coleoptera: curculionidae): A Review

Abstract

The rice weevil, Sitophilus oryzae (Coleoptera: Curculionidae) is a serious, polyphagus, extremely destructive primary pest mainly of rice that infests barley, maize and wheat in storage also worldwide. Its adults are capable of infesting intact grain kernels in the while its grubs feed and complete their development inside grain kernels. Adults prefer to feed endosperm decreasing carbohydrate content. On the other hand, grubs prefer to feed on proteins and vitamins decreasing nutritional value as well as germination capacity. For the management of this insect pest, methyl bromide as well as phosphine has been used as fumigants from past few decades. Inspite of receiving success, the use of these fumigants has been prohibited as these deplete ozone layer. In addition, rice weevils have developed resistance due to its continuous uses. This forced to search new alternatives as eco-friendly safe control systems. In this regard, plant based products like extracts, powders and essential oils have been evaluated and received significant promising results. Biological agents like hymenoptera parasite, predators and entomopathogenic fungi have also been investigated but received little success in this direction. Therefore, combined efforts of different control strategies would be more useful to maximize the protection level from rice weevil infestation.