Seasonal life cycle and biology of Lepidiota mansueta (Coleoptera: Scarabaeidae): a serious root-feeding pest in India

Abstract

the first Indian phytophagous white grub species with nonfeeding adults.

Grub Density of Lepidiota mansueta (Coleoptera: Scarabaeidae) in Different Habitats of the Majuli River Island of Assam, India

“…Presence of highest numbers of L. mansueta grubs in grassland near stream habitat indicates that availability of sufficient soil moisture favoured eggs laying, hatching, growth and development of different life stages; more specifically the pupal stage. Based on available literature on the genus Lepidiota reflects that most of the white grub species belonging to the genus Lepidiota were found to exist either on the Islands or near the river valley (Bhattacharyya et al, 2015). The grubs of L. stigma has been reported to cause extensive damage to maize in river bed areas having loose sandy soil in some parts of Himachal Pradesh of India (Anonymous, 2011).…”

“…Indet., Sophrops irridipennis, Apogonia spp., Adoretus spp. The genus Lepidiota is well-known pests of sugarcane and other agricultural crops in Australia (Allsopp, 2010), India (Gupta, 1969;Anonymous, 2011;Bhattacharyya et al, 2015), Indonesia (Suhartawan, 1995), Nepal (Yubak Dhoj, 2006), Papua New Guinea (Kuniata and Young, 1992), South Vietnam (Ranga Rao and Rameshwar Rao, 2013), Kenya (Mutonyi, 2004) and Philippines (Quimio et al, 2001). In India, Lepidiota mansueta has been reported to cause substantial damage in the Ganges basin of Uttarakhand and Uttar Pradesh (Chandel et al, 2015).…”

“…Of late, L. mansueta had appeared as a severe key pest of many field crops grown in the Majuli, the largest mid-river deltaic island of the world. The tuber damage in potato (Solanum tuberosum), plant damage in sugarcane (Saccharum officinarum) and mung bean (Vigna radiata) and corm damage in taro (Colocasia esculenta) caused by the grubs was 42-48, 15-20, 30-35 and 35-40 per cent, respectively (Bhattacharyya et al, 2015). The abrupt emergence of L. mansueta as a major threat to certain economically important crops of this island may be due to intensive cultivation, conversion of fallow lands in to agricultural lands, deforestation as well as overall changes in the climatic scenario (Bhattacharyya et al, 2013).…”

“…L. mansueta has a biennial life cycle, the first of its kind in North East India. Though it is a biennial white grub species, the third instar grubs were found throughout the year due to mixed population of first year and second year aged grubs of overlapping generations (Bhattacharyya et al, 2015). Moreover, L. mansueta grubs thrive well in wet soil conditions of the Majuli river island and withstand prolonged submergence or flood (Bhattacharyya et al, 2013).…”

“…Though it is a biennial white grub species, the third instar grubs were found throughout the year due to mixed population of first year and second year aged grubs of overlapping generations (Bhattacharyya et al, 2015). Moreover, L. mansueta grubs thrive well in wet soil conditions of the Majuli river island and withstand prolonged submergence or flood (Bhattacharyya et al, 2013). The present investigation on grub density of L. mansueta in five ecologically different habitats of the Majuli river island was carried out to explore the information for ecofriendly and effective management of the grubs.…”