Study of a biological ovipositional deterrent, Myco-Jaal®, a commercial oil based formulation of Beauveria bassiana for enhanced Management of Terphid Fruit Flies

The horticultural crops suffer major economic loss on account of fruit flies belonging to genus Bactrocera spp. across Asia. Bactrocera dorsalis being the most destructive species amongst all the flies in this genus needs special focus and effective management strategies. Reduction of egg laying by female fruit flies can be an effective technique which will lead to large reduction in population and could compliment other IPM strategies like use of lure and cue-lures thereby reduce further crop losses. Beauveria bassiana has a repellent effect on the fruit flies barring them from oviposition on treated fruits. An oil based formulation of 10% Beauveria bassiana “Myco-Jaal^®” was evaluated in the present study. In laboratory studies, the highest tested dose of 6 ml/L reduced the emergence up to 98.7% from the infested fruits. The efficacy of formulated spores is found to be equal to that of unformulated spores hence establishing the potency of the formulation of Myco- Jaal. In field, it was found that a dose of 5 ml/L provided a cost effective solution to the grower reducing the infestation up to 85.5% over the untreated control. A comparison of dip method of treatment with spray application establishes that there is no loss of spores due to drift in spray method hence can be used as a method of application. The biological ovipostional deterrent could well fit into the exiting IPM strategies to further reduce yield and quality losses. The results are discussed in the context of sustainable horticulture intensification in Asia.