An assessment of talc formulation of Hirsutella thompsonii against coconut eriophyid mite (Aceria guerreronis Keifer) in field condition at Karnataka

Abstract

Currently, there are several chemicals have been evaluated against the coconut eriophyid mite Aceria guerreroneis Keifer (Acari: Eriopyidae). But these chemicals are not eco-friendly, chance of development of resistance and have residual effect. Hence, there is need to assess for the safer entamopathogen to manage the coconut mite. Considering this mite pest to cause extensive damage, attempt was made to evaluate the efficacy of Hirsutella thompsonii Fisher for the management of eriophyid mite. The four years pooled data (2014-15 to 2017-18) revealed that spraying of talc formulation of H. thompsonii @20g/palm – 3 sprays during October, January and April was recorded the least mite damaged nuts (58.16%), mite population (10.52 per 4mm2) and Mean Grade Index-MGI (0.81) has been found effective in reducing the mite population followed by spraying H. thompsonii @ 20g /palm during October + botanical formulation (2% Neem oil – garlic – soap emulsion) during January, April treated palms registered the least damaged nuts of (64.01%), mite population (11.24 per 4mm2) and MGI (1.18) and Spraying palm oil – sulphur emulsion – 3 sprays / year during October, January and April recorded fewer damaged nuts of (67.89%), mite population (12.95 per 4mm2) and MGI (1.42) compared to untreated control with higher damaged nuts of (80.49%), mite population (20.50 per 4mm2) and MGI (2.28). It is concluded that spraying of talc formulation of H. thompsonii @ 20g/palm recorded the least mite damaged nuts, mite population per 4mm2 and mean grade index has been found effective in reducing the mite population in coconut at Arsikere centre, Karnataka.