Pulse beetle diversity in Sub Himalayan West Bengal

A study was conducted to investigate the diversity of Callosobruchus spp. (Coleoptera: Chrysomelidae), a major insect pest of stored chickpea in Sub Himalayan region of West Bengal. Chickpea seeds weighing 500 grams were collected randomly from several grocery shops of each of the three districts in northern parts of West Bengal, i.e., Coochbehar, Alipurduar and Jalpaiguri. The seeds collected from different districts were packed and labelled properly and kept in the laboratory and observed until the emergence of pulse beetle, Callosobruchus spp. After emergence, different species of pulse beetles were identified using a modified taxonomic key. Moreover, the specimens were sent to ICAR-National Bureau of Agricultural Insect Resources (NBAIR), Bengaluru for further identification and confirmation. The insect species were deposited in the repository of National Insect Museum, NBAIR, Bengaluru, Karnataka. Four species namely, Callosobruchus chinensis (L.), Callosobruchus maculatus (F.), Callosobruchus analis (F.) and Callosobruchus sp. (Indet.) were found infesting chickpea in the Northern tracts of West Bengal. An account on the species along with well-illustrated photographs is provided in this paper that facilitates easy identification. From this study it can be interpreted that four species of Callosobruchus are found in Sub Himalayan region of West Bengal. Regular monitoring and further exploration of species of pulse beetles is essential to understand the intra and inter-specific variations.