​Bio-efficacy of Chemical Insecticides and Biopesticides against Gram Pod Borer, Helicoverpa armigera (Hubner) and Spotted Pod Borer, Maruca testulalis (Geyer) on Greengram, [Vigna radiata (L.) Wilczek]

Abstract

Background: Gram pod borer, Helicoverpa armigera (Hubner) and spotted pod borer, Maruca testulalis (Geyer) are important pod boring insects infesting the greengram, [Vigna radiata (L.) Wilczek] throughout the India. A number of synthetic insecticides are known to be effective against these borers but most of them have been phased out as a result of high toxicity to the pollinators and other biotic fauna, therefore, a group of new chemical insecticides with biopesticides have been tested for bioefficacy against these insect pests. Method: A field experiment was conducted at S.K.N. College of Agriculture, Jobner, Rajasthan during kharif, 2018 in randomized block design (RBD) with 9 treatments and 3 replications. The observations were recorded of Helicoverpa armigera (Hubner) and spotted pod borer, Maruca testulalis (Geyer) borers one day before and 1, 3, 7 and 15 days after application of insecticides and biopesticides in each the spray from ten randomly selected and tagged plants/ plot. From the data recorded per cent reduction in population over control was calculated. The per cent pod damage was calculated by counting damaged pods out of healthy pods of greengram. Result: The spinosad 45 SC (0.01%) proved to be most effective, indoxacarb 14.5 SC (0.01%) followed by fipronil 5 SC (0.01%), whereas, treatments of neem leaf extract (10.00%), Beauveria bassiana 1.15 WP 1X108 spore/ l proved to be least effective. The maximum seed yield of 9.13 q ha–1 was obtained in the plots treated with spinosad 45 SC (0.01%) followed by indoxacarb 14.5 SC (0.01%) (8.89 q ha-1), fipronil 5 SC (0.01%) (8.60 q ha-1).