Laboratory evaluation of Beauveria bassiana, some plant oils and insect growth regulators against two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae)

The acaricidal activity of entomopathogenic fungus Beauveria bassiana (strain GHA), three essential plant oils namely, neem (Azadirachta indica A. Juss), mahogany (Swietenia mahogoni L.) and karanja (Millettia pinnata L.), and two insect growth regulators (buprofezin and lufenuron) were evaluated against the two-spotted spider mite, Tetranychus urticae Koch under laboratory conditions by leaf disc bioassay method. Results revealed that B. bassiana was highly effective in controlling T. urticae adults causing mortality from 3 days after treatment application. Among the plant oils tested, karanja and mahogany oils were found most effective against T. urticae and both the oils showed significantly better performance compared to all other treatments (P < 0.05). Although neem oil showed comparatively lower toxicity than other plant oils, it was more effective than both the IGRs, buprofezin and lufenuron. However, all the treatments were found effective in controlling T. urticae populations and the study, therefore, suggested that the selected treatments could be considered for biorational management of the T. urticae.