Relative Abundance and Field Efficacy of Insecticides and Bio-control Agents Against Stem Borer Species in Rice (Oryza sativa L.)

Abstract

Background: In India, out of the total loss incurred by different insect pests of paddy, 25 to 30 per cent damage is done by stem borer alone. Many conventional insecticides though have been evaluated against stem borers, yet, most of the chemicals have failed to provide adequate control. Hence, the present study aimed to evaluate the efficacy of some newer molecules of insecticides and bio-control agents.Methods: Field trials were conducted to record the seasonal incidence and to evaluate the efficacy of insecticides and bio-control agents against the stem borer species in rice during Kharif and Rabi. Result: Field experiments revealed that during Kharif 2018, chlorantraniliprole 18.5 SC was highly effective with 92.98 and 91.24 per cent reduction of stem borer infestation over control at vegetative and reproductive stages, respectively and recorded a high yield of 5720 kg/ha followed by spinetoram 11.7 SC with 83.16 and 80.82 per cent reduction of stem borer over control at vegetative and reproductive stages, respectively. During Rabi 2019, spinetoram 11.7 SC was highly effective with 92.36 and 93.73 per cent reduction of stem borer infestation over control at vegetative and reproductive stages respectively and recorded a high yield of 4570 kg/ ha, followed by chlorantraniliprole 18.5 SC with 84.60 and 91.48 per cent reduction of stem borer at vegetative and reproductive stages, respectively. The difference in the efficacy of insecticides during Khaif, 2018 and Rabi, 2019, might be due to shift in the species occurrence of stem borer, with a dominant occurrence of yellow stem borer (80.61%) in Kharif 2018 and pink stem borer (70.00%) in Rabi, 2019. The bio-control agent Trichogramma japonicum exerted minimum reduction of stem borer with a low grain yield of 3946.6 kg/ha.