Field assessment of Biopesticides against Bondar’s nesting whitefly (Paraleyrodes bondari peracchi) in coconut ecosystem

Abstract

Coconut (Cocos nucifera L.) cultivation in India is increasingly threatened by the exotic whitefly, Bondar’s nesting whitefly (Paraleyrodes bondari Peracchi) necessitating the development of sustainable and eco-friendly management strategies. A field experiment was conducted during 2021-22 at HRS, Ambajipeta, to evaluate the efficacy of different biopesticides against whitefly populations under coconut ecosystem. The experiment was laid out in a randomized block design with seven treatments, including four entomopathogenic fungi, one botanical (azadirachtin 10,000 ppm), jet water spray, and an untreated control, with five replications. Observations on nymphs and adults were recorded at 7, 14 and 21 day intervals following spraying. Among the treatments, Isaria fumosorosea (NBAIR pfu-5 @ 5 ml L⁻¹) was most effective, significantly reducing whitefly populations and recording the highest reduction over pre-treatment counts with 58.42% reduction of nymphs and 80.10% reduction of adults. Azadirachtin 10,000 ppm ranked next in efficacy, followed by Lecanicillium lecanii, Beauveria bassiana, whereas Metarhizium anisopliae showed comparatively lower effectiveness. Jet water spray provided only marginal control, whereas the untreated control recorded a progressive increase in pest population. The superior performance of I. fumosorosea may be attributed to its ability to produce cuticle-degrading enzymes, facilitating rapid infection and mortality of whitefly stages. The study clearly demonstrates the potential of entomopathogenic fungi and botanicals as effective, environmentally safe components of integrated pest management (IPM) strategies for sustainable management of exotic whitefly complex in coconut.