P-105 Screening for Insecticide-Producing Streptomyces Isolates from Thai Soil

Total of 359 Streptomyces isolates were obtained from Thai soil. They were screened for insecticidal activity using brine shrimp bioassay. Five isolates (1.39%) showed potential insecticidal activity. Of 5 isolates, 3 isolates namely 442, 449 and O145702 showed strong insecticidal activity. The activity was found in both mycelium and culture supernatant. The ethyl acetate extracts of the whole culture of these strains were subjected to MS analysis. The results showed that molecular masses of all compounds produced by these strains were different from those of the common commercial insecticides, avermectins, abamectins Ba and Bb produced by Streptomyces avermitilis which have molecular masses of 860, 858 and 872, respectively. From the preliminary analysis, these strains may produce novel insecticidal compounds