Potential of secondary metabolites from soil-derived actinomycetes as juvenile hormone disruptor and insecticides

Actinomycetes represent sources of potential alternatives to chemicals as biological pest control agents, and several actinomycetes are known to produce metabolites with insecticidal activities against insect pests. Although these metabolites are eco-friendly and effective, it is necessary to identify a novel insect-specific insecticidal agents that can minimize the occurrence of resistance. Thus, in this study, we screened the juvenile hormone disruptor (JHD) and insecticidal activities of crude acetone extracts derived from various actinomycetes as novel biopesticide candidates. A total of 300 soil-derived actinomycetes were isolated from various sites in Korea, and were screened for their JHD and insecticidal activities against a range of important medical and agricultural pests. Among them, eight extracts showed high levels of JHD activity. The AN120590 strain showed a broad insecticidal spectrum with stably maintained JHD properties. Additionally, the dead larvae of Aedes albopictus and Plutella xylostella treated with acetone extracts of the AN120590 strain displayed morphological deformities similar to those of insects treated with juvenile hormone-based insect growth regulators (IGRs). These findings indicate that actinomycetes represent promising sources of novel IGRs that can be effectively applied as insecticides with a broad insecticidal spectrum.