Vol. 11, Issue 5 (2022)

Author(s):
Suman Balikayi, R Channakeshava, Shalini N Huilgol and Prasanna PM

Abstract:
Tobacco caterpillar, Spodoptera litura (Fab.) (Lepidoptera: Noctuidae), was reared on soybean leaves and the second instar larvae were selected to conduct bio-assay under in-vitro condition. The larvae were treated with different combinations of microbial bio-pesticides under laboratory conditions. Spore suspensions of microbial conidia were imposed on larvae with topical spray and leaf dip method. Results of the investigation revealed that Metarhizium rileyi (2x10⁸ cfu/g) was most effective treatment against Spodoptera litura with highest larval mortality (100%) followed by the treatment M. rileyi + Bacillus thuringiensis var. kurstaki (Btk) after a week of treatment imposition. The least pupation (8.34%) was observed in larvae treated with Beauveria bassiana (2x10⁸cfu/g). A sequential follow up from this assay was done on the resulting pupae and adults, if any. Further treatment of the resultant pupae caused mortality and adult malformation. The healthy moth emergence and fecundity was least in B. bassiana (5%). Thus, the present investigation confirmed the efficacy of different combinations of microbial bio-pesticides against S. litura that can be exploited under field condition while planning for pest control strategies in an eco-friendly manner.