Biocontrol-based management module provided maximum protection in potato against white grub, Lepidiota mansueta Burmeister in Assam, India

Abstract

Background The present study was conducted to evaluate the efficacy of some eco-friendly management modules based on plant oils and Metarhizium anisopliae against a biennial white grub species, Lepidiota mansueta Burmeister (Coleoptera: Scarabaeidae) infesting potato crop in the farmer’s field at Majuli river island, Assam, India. Results Amongst all the modules evaluated against L. mansueta grubs, the pooled analysis of two years of data (2019–2020 and 2020–2021) revealed that Module-VI [presowing treatment of mustard oil cake @ 150 kg/ha + wood ash @ 150 kg/ha + panchagavya @ 3% plus the application of Metarhizium anisopliae @ 10 g/sq.m after 1st & 2nd earthing up (25 & 60 Days after Sowing (DAS))] and Module-III [presowing treatment plus soil drenching with jatropha oil @ 5 ml/lit after 1st & 2nd earthing up (25 & 60 DAS)] were significantly superior and statistically at par over the rest of the modules in recording high yield (122.71 and 121.50 q/ha, respectively), minimum per cent tuber damage on weight basis (11.32 and 11.82%, respectively) and number basis (14.07 and 14.78%, respectively). The maximum benefit cost ratio was recorded in Module-VI, followed by Module-III and Module- II. Conclusion All the management modules were effective, however, Module-VI and Module-III were found to be significantly superior and registered the least tuber damage on weight and number basis and the highest tuber yield compared to other modules.