Abstract

The present study was carried out to trace the life cycle of mealy bug, Rhizoecus amorphophalli on three different hosts including elephant foot yam, taro and tannia tubers. Investigation revealed that the mealy bug reproduces sexually and the adult female secretes an egg sac of white waxy substance in which eggs were laid. Female nymph moult normally, but male instar produces a cottony puparium around its body and form a pupal stage from which adult males emerge. On tubers of elephant foot yam, average fecundity and incubation period were 68.30±6.22 and 7.80±0.88 days respectively. But, it was significantly lesser for those on the taro and tannia tubers. Nevertheless irrespective of hosts, the percentage of hatching maintained uniformity. The total life cycle of bug which includes three instars and a pupal stage took 27.10 days for females and 22.40 days for males on tubers of elephant foot yam. The larval stages of mealy bug did not show prominent morphometric changes among the hosts used for life cycle study.

Key words: Rhizoecus amorphophalli, elephant foot yam, taro, tannia, mealy bug, biology, life cycle.