Field evaluation of horticultural mineral oils and botanicals against bean thrips, Megalurothrips distalis (Karny) (Thysanoptera: Thripidae), in summer mung bean

Abstract

Abstract Background Bean thrips, Megalurothrips distalis (Karny), are a serious insect pest of mung bean grown in summer season as a catch crop in wheat–rice cropping system in North West India. Severe incidence leads to flower shedding and fewer pods leading to loss in grain yield. Field studies were conducted to evaluate the efficacy of horticultural mineral oils, neem-based botanicals, and pongamia soap in the form of spray in comparison to the insecticide dimethoate in 2018 and 2019. Main body Randomized complete block design (RCBD) was used with 11 treatments including untreated control in 3 replications. Neem seed kernel extract (NSKE) at 5% gave the highest mean percent reduction in the number of thrips (90.44 and 79.59%), followed by 10 ml l−1 of Neem Kavach 1500 ppm (85.55 and 78.97%) and the insecticide dimethoate 30% EC at 250 ml ha−1 (84.92 and 78.22%) 1 and 3 days after treatment. Neem Baan 1500 ppm, Indo-Neem 1500 ppm, and Nimbecidine 300 ppm each at 10 ml l−1 also provided 75.29–82.42% and 61.18–75.82% reduction 1 and 3 days after treatment. Horticultural mineral oils also reduced the insect population by about 64%, while pongamia soap was least effective (31.58%) among botanicals. Dimethoate 30% EC at 250 ml ha−1 recorded the highest grain yield and net returns, followed by NSKE, Nimbecidine, and Neem Kavach that were on par with it. Homemade neem extracts evaluated in 2019 caused 62.7–77.3% reduction in thrips population up to 3 days after treatment with yields comparable to 10 ml l–1 of Indo-Neem spray. Conclusion The study indicated that neem extract was capable to manage the bean thrips in flowers of summer mung bean and obtained a high grain yield.