Susceptibility of Duponchelia fovealis Zeller (Lepidoptera: Crambidae) to different entomopathogens in laboratory conditions

Abstract

ABSTRACT Duponchelia fovealis Zeller, is currently considered one of the most important emergent pests of a range of crops. This pest is common in Europe, but its presence in the Americas, particularly Brazil and Mexico, has been only recently reported in strawberry crops. Since its recent arrival in Mexico interest in the potential of different entomopathogens for the control of D. fovealis has increased. Here we evaluated commercial products of the bacterium Bacillus thuringiensis; three different species of entomopathogenic nematodes; and different isolates of four species of entomopathogenic fungi. All pathogens were evaluated against 3rd instar larvae, except nematodes which were evaluated against both larvae and pupae. Analysis revealed significant differences in virulence amongst B. thuringiensis products, where the most virulent was nine times more virulent than the least virulent product. Amongst nematodes, Heterorhabditis bacteriophora was the most virulent and larvae were more susceptible to nematodes than pupae; larval mortalities at the highest dose evaluated (200 infective juveniles [IJs]) were between 80 and 95%, while for pupae they were between 25 and 40%. Mortality of larvae due to entomopathogenic fungi was lower than for the other entomopathogens; the highest mortality observed was 25% caused by an M. anisopliae isolate, although this was not statistically different to other fungal isolates. Overall, our results showed that biological control products based on B. thuringiensis or the nematode H. bacteriophora have the greatest potential; we consider that H. bacteriophora could be more convenient as it infects larvae and pupae.