Efficacy of Purpureocillium lilacinum CKPL-053 in controlling Thrips palmi (Thysanoptera: Thripidae) in orchid farms in Thailand.

Ten entomopathogenic fungi were tested for the control of female adult Thrips palmi Karny in the laboratory. The most virulent fungus Purpureocillium lilacinum CKPL-053, two commercial bioinsecticides and a chemical insecticide were tested for control of T. palmi in two Dendrobium sp. orchid farms. Controls of T. palmi in both farms were highest with P. lilacinum CKPL-053. Purpureocillium lilacinum CKPL-053 and the Odashima strain P. lilacinum produced paecilotoxins A, B, and C when cultured in complete medium 1 but not in potato dextrose broth. Jasmonic acid contents in Dendrobium sp. petals after application of P. lilacinum CKPL-053, B.bassiana CKB-048, M. robertsii CKM-048, and P. lilacinum CKPL-012 spore suspensions were significantly higher than with imidacloprid and water control treatments. This suggests that jasmonic acid might assist in activating plant defense mechanism to exhibit the repellence and/or resistance effect of Dendrobium sp. against T. palmi. The LC and LT for P. lilacinum CKPL-053 against female T. palmi were 2.67 × 10 conidia ml and 2.6 days at the concentration of 1 × 10 conidia ml, respectively. [ABSTRACT FROM AUTHOR]