Characterization of insecticidal compound from Streptomyces gramineus against Thrips palmi.

[Display omitted] • Actinomycete IMBL-2090 showed high insecticidal activity against T. palmi. • IMBL-2090 was identified to Streptomyces gramineus. • Phenylacetic acid was isolated as main insecticidal compound from IMBL-2090. Thrips palmi, also known as melon thrips, is one of the serious phytophagous sap-sucking insects that not only damages a wide range of crops but also serve as a vector for plant viruses. Actinomycetes have been reported to produce various insecticidal compounds such as spinosad and avermectin, suggesting that secondary metabolites from actinomycetes could be useful biological insecticides. In this study, culture filtrates of 174 actinomycetes isolates were screened for their insecticidal activity against T. palmi. Among them, Streptomyces IMBL-2090 showed superior insecticidal activity with 100% mortality and no acute fish toxicity. Through bioassay-guided fractionation using culture filtrate of IMBL-2090, phenylacetic acid was identified as the major insecticidal substance. These results suggested that Streptomyces IMBL-2090 could be exploited as an effective biological insecticide for control of T. palmi. [ABSTRACT FROM AUTHOR]