Sustainable Pest Management: Compatibility of <i>Metarhizium anisopliae</i> with Botanical and Chemical Insecticides

Chemical pest control is effective and widely used in agriculture because it can quickly reduce pest populations. However, it has significant environmental and agronomic impacts. This study assessed the “in vitro” compatibility of the entomopathogenic fungus Metarhizium anisopliae (Metchnikoff) Sorokin with deltamethrin and neem oil insecticides. We used three fungal isolates obtained from the commercial product Metarril® WPE9. Bioassays measured the effect of the insecticides on vegetative and reproductive parameters. The results showed that deltamethrin stimulated the vegetative growth of the three isolates tested and was compatible with the fungus at all the doses evaluated. However, neem oil reduced the growth and germination of the isolates at the highest concentration, being classified as moderately toxic. Deltamethrin showed potential for use in addition to M. anisopliae in integrated pest management (IPM) programs due to its compatibility. Neem oil showed compatibility at commercial concentrations but toxicity at the highest concentration, indicating that its combined use with M. anisopliae should be carefully evaluated. This study allowed us to understand the interactions between entomopathogenic fungi and insecticides, providing valuable information for adopting biological control strategies in agricultural systems.