DNA barcoding reveals the natural occurrence of Beauveria bassiana (Balsamo) Vuillemin in two-spotted spider mite, Tetranychus urticae Koch in Bhendi [Abelmoschus esculentus (L.) Moench] ecosystem in Coimbatore district of Tamil Nadu.

COIMBATORE (India); TAMIL Nadu (India)

Background: Two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae) incidence is a major constraint in vegetable cultivation. The indiscriminate use of acaricides is causing environmental threat and also residual effect in vegetables. To develop an eco-friendly management strategy, an investigation was made to access the natural occurrence of entomopathogenic fungi (EPF) infecting mites in bhendi, India ecosystem. Results: Natural incidence of EPF was high during the month of December. Twelve EPF isolates were isolated from the mycosed T. urticae cadavers using Potato Dextrose Agar Medium. Morphological studies confirmed that the isolated fungi were Beauveria bassiana. PCR amplification of ITS region was carried out and the results showed, amplification at 560 bp. In NCBI database, the sequence of the virulent isolates had shown 99.2, 98.7, 99.1, 97.7 and 96.8% homology with other B. bassiana isolates, confirming the occurrence of B. bassiana mycosed mites in vegetable ecosystem. Conclusion: The isolate MZ749636 (B.b-7) was found to be virulent against T. urticae causing 86% mortality of T. urticae at the conidial load of 1 × 108 conidia/ml at laboratory conditions and so it could be utilized for the eco-friendly management of T. urticae. [ABSTRACT FROM AUTHOR]