The white halo fungus, Lecanicillium lecanii was evaluated for its insecticidal activity against larvae, pupae and adult stages of the American bollworm, Helicoverpa armigera. In general, the highest concentration of the fungus led to least pupation. The length of larvae and pupae did not vary between the fungal treatments, while the weight showed a significant variation. Prolongation in Larval and pupal duration and as a result, high percentage of malformed adults was noted. Subsequent effect on adults, particularly, the longevity and fecundity was reduced in the highest cone. The biosafety tests on Trichogramma sp. proved that even at the highest conc. the parasitization was on par with the untreated.