Beauvericin, synthesized by entomopathogenic fungi, as a promising natural pesticide of Leptinotarsa decemlineata.

BACKGROUND Beauvericin (BEA) is a secondary metabolite produced by Beauveria bassiana, Isaria fumosorosea and Fusarium spp., known for its insecticidal properties. Leptinotarsa decemlineata, commonly known as the Colorado potato beetle, is a major pest that feeds primarily on potato plants. Over time, this species has developed resistance to many conventional insecticides, highlighting the need for novel control agents. BEA was purified from three B. bassiana and three I. fumosorosea strains using a molecularly imprinted cryogel column and tested for its efficacy against fourth-instar larvae of L. decemlineata. To determine the optimal method for its application, BEA derived from the B. bassiana Lul1 isolate was initially evaluated using three methods: injection, spraying and leaf-dipping. RESULTS The lethal time for 50% mortality for the injection, spraying and leaf-dipping methods were determined to be 7.8, 8.5 and 9.7 days. The spraying method was selected for subsequent dose-mortality studies using four concentrations of BEA from three B. bassiana and three I. fumosorosea isolates, and a commercial BEA. Significant differences in the lethal concentration for 50% mortality (LC₅₀) values were observed across different post-exposure times. On days 5, 8 and 10, LC₅₀ values were 218.39, 0.07 and 0.04 μg/mL, respectively for the extract obtained from the B. bassiana isolate KVL 03129. CONCLUSION In conclusion, BEA has significant potential as an effective insecticide candidate for controlling L. decemlineata populations, offering a promising alternative to traditional chemical insecticides. © 2025 Society of Chemical Industry.