Activity of oil-formulated conidia of Nomuraea rileyi and Paecilomyces tenuipes against Spodoptera, Heliothis and Helicoverpa larvae and pupae

Conidia of nine strains the entomopathogens Nomuraea rileyi and Paecilomyces tenuipes were formulated in mineral and vegetable oils for topical bioassays against larvae of Helicoverpa zea, Heliothis virescens, Spodoptera exigua and Spodoptera frugiperda and prepupae and pupae. Most oils were compatible with both fungi, allowing the induction of infections. Nomuraea was more active than Paecilomyces against larvae. Among larvae, Heliothis virescens was the less susceptible species to Nomuraea. This fungus induced high mortality levels in Spodoptera spp. larvae at operational doses (<10⁸ conidia/ml). Paecilomyces tenuipes caused infections in pupae. The use of oil-formulated conidia of Nomuraea and Paecilomyces tenuipes against lepidopterans warrants further investigation under field conditions.