Potential of microbial control agents in a strategy against Duponchelia fovealis Zeller (Lepidoptera: Crambidae)

The use of entomopathogenic microorganisms represents a viable alternative in managing Duponchelia fovealis (Lepidoptera: Crambidae). In the present study, we evaluated the mortality of immature stages of D. fovealis caused by entomopathogenic fungi and commercial bioinsecticides under laboratory conditions. The most virulent strains were Beauveria bassiana 4485 and 4488, which led to mortality rates higher than 80% for thirdinstar larvae. Mortality rates for these strains were higher than 50% in the first larval stages. However, a reduction to 8.31% and 32% for 4485, and 6.74% and 33% for 4488, was recorded in eggs and pupae, respectively. The most pathogenic commercial product was based on the HD-1 strain of Bacillus thuringiensis (Bt), which had a mortality rate higher than 90%. This product decreased the survival rates of D. fovealis larvae more rapidly than B. bassiana strains, with a mean survival time of 85.52 h after seven days of exposure. Initial developmental stages of D. fovealis showed higher lethality, with a mortality rate of 91.75% for the first instar and 79.79% for the second instar. Our results show that B. bassiana strains 4485 and 4488, and the HD-1 Bt-based product have potential to control D. fovealis. However further studies in the field are needed to assess their potential as an effective management strategy.