Abstract:
The present study constitutes a laboratory investigation of the life history parameters of the predatory bug Orius laevigatus (Fiber) when predated on the tobacco whitefly Bemisia tabaci (Gennadius). The later was offered on
tomato and eggplant leaf discs under laboratory constant conditions of 25±1°C, 75±5% R.H and 16 L: 8 D photoperiod regime. Both nymphs and adults of O. laevigatus were able to feed on eggs and larvae of B. tabaci
when offered on tomato or eggplant leaf discs. The preference for feeding on B. tabaci eggs was higher than that on larvae. During all nymphal stages, O. laevigatus consumed an average of 364.7 and 283.5 of B. tabaci eggs
and larva when reared on tomato and eggplant leaf discs, respectively. In addition, during adulthood, adult females of O. laevigatus consumed an average of 883 and 455 of B. tabaci eggs and larva when reared on tomato
and on eggplant, respectively. Thus, adult longevity and fertility of O. laevigatus were greater when fed on B. tabaci infestation offered on tomato rather than on eggplant. The survival of O. laevigatus was found to fit to
Type II when fed on B. tabaci infestation offered on tomato, but to Type III on eggplant. The rate of predation and fertility of O. laevigatus was affected by the host plant. Further investigations have to be done on the practical use of O. laevigatus as a bio-control agent against B. tabaci infestation on tomato and eggplant.
