Lifehistory of mealybug Phenacoccus solenopsis tinsley (Hemiptera Pseudococcidae) on different host plants and its relative effect of antibiosis

摘要

Phenacoccus solenopsis Tinsley, (Hemiptera; Pseudococcidae) is a serious pest of many agronomic and horticultural crops in the world. Present research was conducted in Department of Entomology, Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi Pakistan. The research was performed in two experiments. For experiment I, life history parameters (Female and male developmental time, s urvivorship, sex ratio, female longevity and fecundity, relative growth rate and intrinsic rate of population in crease) were observed on five different horticultural plants hibiscus, okra, brinjal, chrysanthemum and cucumber. In experiment II, 3 preferr ed hosts for P.solenopsis were chosen, the hosts were shuffled and effect of antibiosis characteristics were observed for similar life history parameters. In experiment I, The results revealed male and female developmental time as shorter on hibiscus, okra and brinjal. The longevity and fecundity was associated with developmental rate. The females laid more number of sacs with shorter life span suggesting hibiscus, okra and brinjal to be suitable hosts compared with chrysanthemum and cucumber. The ovipositi on period can also be related to the higher number of egg sacs laid. Nymphs fed on hibiscus, okra and brinjal survived more, while on cucumber and chrysanthemum showed high mortality. Low survival could be credited to the unsuitability of hosts. Higher rel ative growth rates, reproductive and intrinsic rates on hibiscus and okra reinforces that these plants are more favorable hosts. It reflects the potential of host plant to add to P. solenopsis population. While, in experiment II, the findings indicated tha t the shuffling of hosts effect negatively to the developmental time, longevity and fecundity. The P. solenopsis showed best growth rate when reared on same hosts but it decreases when replaced with alternative hosts. The survival rate was decreased after shuffling the hosts and the same trend was observed for the net reproductive and intrinsic rates of population increase.