Bio-efficacy of novel chemicals and tribal pesticide-based integrated modules against brown planthopper in rice

Abstract

Rice brown planthopper (BPH), Nilaparvata lugens (Stal.) is a major menace and cause of significant damage to rice throughout Asian countries. Farmers mostly rely on conventional chemical insecticides to control this pest, however injudicious application of chemicals lead to the problem of insecticide resistance and environmental pollution. Considering the economic importance of BPH a research was conducted during kharif season 2018–2019 to investigate the field-efficacy vis.-a-vis. non-target toxicity and economics of some bio-rational pest management schedules at a BPH biotype 4 endemic location (Burdwan district) of West Bengal, India. Among various treatment schedules, triflumezopyrim (30 g a.i. ha−1), pymetrozine (175 g a.i. ha−1) and sulfoxaflor (30 g a.i. ha−1) in a rotational application with aqueous extract of Jatropha gossypiifolia + cow urine @ 1:1 ratio (3.5%) and aqueous extract of Argemone maxicana + ‘toddy’ @ 1:2 ratio (3.0%) significantly reduced the nymphs and adult populations of BPH. The aforesaid insecticides and indigenous components were also found to be safe to prevailing predatory fauna including Cyrtorhinus lividipennis, Ophionea spp. and spider complex in the field. Though there was a short-term decline in predatory populations after application of insecticides, it started increasing gradually within a week after treatment. Yield of rice significantly increased over control in those treatment schedules during both the years with an incremental cost: benefit ratio of 1:2.62 to 1:3.99. These superior semi-organic modules, as an approach towards “eco-friendly agriculture”, can be an excellent alternative of truly chemical schedules in controlling rice BPH in coming years.