Efficacy of Selected Insecticide and Biopesticide Combinations against Major Insect Pests of Late Maturing Pigeonpea [Cajanus cajan (L.) Millsp.]

Abstract

Aim: To evaluate the comparative efficacy of different chemical insecticide and biopesticide combinations against tur pod fly [Melanagromyza obtusa (Malloch)], gram pod borer [Helicoverpa armigera (Hübner)] and tur pod bug (Clavigralla gibbosa Spinola) on pigeonpea. Study Design: Randomized Block Design with three replications. Place and Duration of Study: Field experiments were conducted at Agriculture Research Farm, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi during Kharif seasons of 2015-16 and 2016-17. Methodology: The experiment consisted of eight treatments having different combinations of insecticides and biopesticides including untreated control. Effectiveness of these treatment regimes was determined on the basis of per cent pod and grain damage due to major insect pests and grain yield of pigeonpea. Results: Treatment regimes having combinations of chemical insecticides and biopesticides were found to be more effective in comparison to treatments modules where there was sole use of biopesticides. The treatment comprising of sequential application of Multineem 0.03% followed by second spray of Rynaxypyr 18.5 SC @ 30 g a.i./ha and third spray of Indoxacarb 15.8 EC @ 73 g a.i./ha at 15 days interval was significantly superior in managing M. obtusa, H. armigera and C. gibbosa on pigeonpea over rest of the treatments in terms of lower pod and grain damage and higher grain yield. However, all the insecticidal treatment modules were found significantly superior over untreated control. Conclusion: Sequential application of Multineem 0.03% - Rynaxypyr 18.5 SC @ 30 g a.i./ha - Indoxacarb 15.8 EC @ 73 g a.i./ha may be considered for recommendation in alternate sprays for managing major insect pests on long duration pigeonpea in Varanasi region of Indo-Gangetic plain.