Impact of Bt Cotton on Incidence of Insect Pest and Diseases

The present study was conducted in Dharwad, Davanagere, Gadag and Mysore district during the year 2011. These districts are selected based on highest area under Bt cotton cultivation and these districts incidentally represents all the agro climatic zones of the state. The total sample size for the study was 5000. Findings of the study revealed that, in case of boll worms, including American, pink and spotted boll worms, low/no infestation was indicated by over 85 per cent of respondents and such incidents were reported as severe in non Bt cotton as opined by about 60–70 per cent of respondents. About 80.76 per cent of respondents opined that mirid bug was the major insect pest emerged after introduction of Bt cotton followed by shoot weevil (79.38%). Further, the refugia management reveals that most of the respondents (72.32%) were unaware of the refugia concept. Majority of the respondents (74.01%) were not adopting refugia as recommended by the scientists. Further, regarding the usage of the non-Bt (refugia) seeds supplied with the Bt cotton seeds, majority of the respondents (40.52%) used it for gap filling and 29.04 per cent of the respondents used the non-Bt seeds for other fields.