S.B. PatilAyyanna B.2016-11-212016-11-212012http://krishikosh.egranth.ac.in/handle/1/86835Field experiments were carried out on population dynamics and management of shoot weevil, Alcidodes affaber Auriv. on Bt cotton during 2011-12 at ARS, Dharwad Farm, University of Agricultural Sciences, Dharwad. The incidence of shoot weevil in 20-06-2011 sown crop varied from 1.00 to 22.00 in Kanaka Bt and 0.00 to 19.00 /100 plants in DCH 32 non Bt. Similarly, the activity of the adult in 05-07-2011 sown crop ranged between 0.00 to 18.00 (Kanaka Bt) and 0.00 to 17.00 (DCH32)/100 plants respectively. The percentage of plant damage in the first sown crop of Kanaka and DCH 32 ranged from 23.00 to 100.00 and 10.00 to 95.00 per cent respectively. The maximum infestation of 100.00 and 95.00 per cent was recorded in Kanaka and DCH 32 in the first fortnight of October. Similarly, the infestation of shoot weevil in second sown crop varied from 25.00 to 93.00 per cent and 23.00 to 91.00 per cent in Kanaka and DCH 32 hybrids. The adult shoot weevil population was positively correlated with high rainfall, relative humidity and low temperature which indicated that these factors were congenial for increased activity of shoot weevil during both the sowings. The survey carried out to know the status of shoot weevil in different cotton growing areas viz., high, moderate and low rainfall ecosystem revealed that higher infestation of shoot weevil was recorded in high rainfall ecosystem. Among the three surveys that were carried out over a period of 90 days right from the date of sowing indicated that the crop up to 90 days was found to be more vulnerable for shoot weevil attack. Management of cotton shoot weevil involving insecticides, trap crop (okra), mechanical collection and destruction of weevils revealed the superiority of Thiodicarb 70 WP + DDVP 76 EC and Profenophos 50 EC+ DDVP 76 EC application. The application of Thiodicarb 70 WP was found to be the next best treatment. Trapping weevils on okra and mechanical collection were observed to be less effective compared to insecticidal application.Thesis