Entomopathogenic fungi have been used recently for the management ofwhite- fly （Bemisia tabaci） and diamondback moth （Plutella xylostella）. In previous studies, lsaria fumosoroseus has shown some potential to control these insect pests. In this paper, the ef- fects of I. fitmosoroseus （strain PF0 l-N4） on the mortality, fecundity and other life table parameters were observed under laboratory conditions. As a first step, the susceptibility of second instars ofB. tabaci and P. xylostella was examined in dose-response experiments, which was followed by the studies on the effect of/. fumosoroseus on reproduction. Both B. tabaci and P. xylostella, were susceptible to I. fumosoroseus having median lethal con- centration values ofl.10 x 104 and 0.48 ~ 104 conidia/mL after 12 and 11 days treatment, respectively. The fungal infection significantly reduced the longevity and fecundity of B. tabaci. At 1 ~ 107 conidia/mL, a minimum average longevity of 9 days was observed as compared to 16.3 days for the control. Similar results were also observed in P. xylostella with an average longevity of 5.6 days as compared to 17.68 days in the control. In case of reproduction, the number of progeny produced by B. tabaci and P. xylostella decreased with an increase in conidial concentration, with the average values of 83.67 and 26.85, 10.92 and 225.51,112.08 and 31.02 eggs/female for control, 1 × 10^4 and 1 × 10^7 conidial/mL, respectively. There was a significant effect of L. fumosoroseus on intrinsic rate of natural increase.
