Effect of Isaria fumosoroseus on mortality and fecundity of Bemisia tabaci and Plutella xylostella

Abstract

Abstract Entomopathogenic fungi have been used recently for the management of whitefly (Bemisia tabaci) and diamondback moth (Plutella xylostella). In previous studies, Isaria fumosoroseus has shown some potential to control these insect pests. In this paper, the effects of I. fumosoroseus (strain PF01‐N4) on the mortality, fecundity and other life table parameters were observed under laboratory conditions. As a first step, the susceptibility of second instars of B. tabaci and P. xylostella was examined in dose‐response experiments, which was followed by the studies on the effect of I. fumosoroseus on reproduction. Both B. tabaci and P. xylostella, were susceptible to I. fumosoroseus having median lethal concentration values of 1.10 × 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 × 104 and 1 × 107 conidial/mL, respectively. There was a significant effect of I. fumosoroseus on intrinsic rate of natural increase.