Shashidhar ViraktamathVinayak Pise2016-11-122016-11-122011http://krishikosh.egranth.ac.in/handle/1/85221Comparative studies on pollinator fauna, foraging activity of honey bees and effect of indigenous bee attractants on bee visitation and yield parameters of Bt and non-Bt cotton were made during Kharif season of 2010 at Dharwad. Among 18 species of pollinators, Apis dorsata F., was the most dominant (29.83 %) followed by A. cerana F. (25.21 %) and A. florea F. (22.54 %). Activity of honey bees was observed throughout the day with a peak at 1200 h in both Bt and non-Bt cotton. No significant difference in the activity was observed between Bt and non-Bt cotton hybrids. Indigenous bee attractants (Citral E, Citral Z, Fagara budrunga, Swertia densifolia) were equally effective in attracting significantly more number of bees (2.25 to 3.25 and 2.17 to 3.17 bees /10m2/5 min in Bt and non-Bt cotton, respectively) which was as good as the Fruit boost, a commercial bee attractant. However, there was no significant difference among Bt and non-Bt cotton hybrids with respect to bee visitation. Bee attractants enhanced the yield parameters viz, good opened bolls (8.37 to 9.56 and 7.18 to 8.25 % in Bt and non-Bt cotton, respectively), seeds per boll (10.82 to 21.89 and 10.67 to 16.64%), lint yield (5.80 to 7.83% and 4.85 to 5.13), seed yield (11.60 to 14.02 and 7.63 to 11.84%) and kapas yield (10.39 to 15.05 and 8.56 to 12.65%). At the same time there was a decline in the bad opened bolls (30.82 to 28.53 and 22.22 to 16.66 %) both in Bt and non-Bt cotton hybrids. The extent of increase in the total yield due to spray of indigenous bee attractants was more or less similar both in Bt (10.39 to 15.05 %) and non-Bt cotton (8.56 to12.65 %) hybrids.Agricultural EntomologyThesis