An update of mirid bug infestation in Bt cotton fields of Haveri and Dharwad districts of Karnataka, India

Abstract

Mirid bugs are important sucking insect pests of Bt cotton ecosystem in Karnataka. The substantial symptoms and damage inflicted by mirid bugs leads to significant economic losses to the cotton crop. To have an updated understanding about the pest, roving field surveys were conducted during 2023-24 in cotton ecosystem of Haveri (Ranebennur, Haveri, Bydagi, Savanur) and Dharwad (Dharwad, Hubballi, Kalaghatagi) districts, of Karnataka. The highest number of mirid bug incidence, square shedding, boll shedding, parrot beaked bolls and bolls with scars were noted in Haveri district (5.10 ± 2.52 bugs/ 5 squares), (1.90± 1.67 squares/plant), (1.54± 0.38 bolls/plant), (3.14± 0.75 bolls/plant) and (4.37± 0.52 bolls/ plant), respectively. However, the incidence of the pest in Dharwad district found significantly lower than the Haveri district (3.88±2.02 bugs/ 5 squares), (1.02±0.82 squares/plant), (0.89±0.29 bolls/plant), (2.38 ± 0.13 bolls/plant) and (3.07± 0.53 bolls/plant). Among different taluks, Haveri taluk cotton fields exhibited the highest incidence, followed by Byadagi and the lowest incidence was observed in Kalghatagi taluk. Across various cotton cultivars, the highest mirid bug incidence and associated damage was recorded in BGII cotton hybrid MRC-7351, while the lowest in US-7067. These findings underscore the necessity for targeted pest management strategies in cotton ecosystems to mitigate mirid bug incidence effectively.