Assessment of Entomopathogenic Nematodes in Oil Emulsions to Control Scyphophorus acupunctatus in Agave under Laboratory Conditions

The weevil Scyphophorus acupunctatus Gyllenhal causes damage and losses in agave crops and has traditionally been controlled using contact and systemic agrochemicals. Implementing microbial control strategies is proposed as an alternative to mitigate the environmental impact associated with agrochemicals. The objective of this study was to determine the survival of entomopathogenic nematodes in oil emulsions for the control of adult S. acupunctatus. Three species of entomopathogenic nematodes were evaluated: Steinernema carpocapsae, S. glaseri, and Heterorhabditis bacteriophora. We used two concentrations (50 ± 5 and 100 ± 10 infectious juvenile nematodes), and oil emulsions derived from Salvia hispanica, Triticum vulgare, and Olea europea with oil purity of 20% and 40%. The effectiveness of these treatments was assessed by determining the mortality rate of S. acupunctatus. The results indicate that the combination of S. glaseri and H. bacteriophora, at concentrations of 50 ± 5 and 100 ± 10 nematodes, respectively, with T. vulgare and O. europea oils, achieved a mortality rate of 85.76% in S. acupunctatus adults at 24 h. At 120 h, a mortality rate of 100% was achieved with specific formulations, such as S. glaseri with 100 ± 10 nematodes + O. europea, and H. bacteriophora with 100 ± 10 nematodes + O. europea. Consequently, we conclude that oil formulations combined with nematodes show potential as an effective and environmentally friendly alternative for the control and management of S. acupunctatus.