Impact of weather parameters on pollinator activity in cauliflower (Brassica oleracea var botrytis L) seed crop in mid-hills of Himachal Pradesh

The activity of insect pollinators visiting cauliflower (Brassica oleracea var botrytis L) seed crop was studied at Nauni, Saproon and Kandaghat in Solan district of Himachal Pradesh during 2014–15 and 2015–16. Four classes of pollinators viz honeybees, syrphid flies, wild bees and other insect pollinators (butterflies, moths, beetles etc) were recorded on cauliflower seed crop at these study locations. The highest number of insect pollinators was recorded at Saproon (26.2 insects/5 plants) followed by Kandaghat (23.6 insects/5 plants) and lowest was recorded at Nauni (18.0 insects/5 plants) in the first week of observation. During second week the number of insect pollinators was 24.8, 33.6 and 30.1 per 5 plants at Nauni, Saproon and Kandaghat respectively. Among different pollinators honeybees were most frequent visitors. The average number of honeybees recorded per 5 plants was 38.4 and 49.5 during first and second observation week respectively followed by syrphid flies (27.4 and 36.4 respectively), other insect pollinators (14.5 and 18.9 respectively) and other wild bees (9.9 and 13.0 respectively). The maximum temperature influenced the foraging activity of pollinators positively whereas forenoon humidity exhibited negative effect on number of pollinators visiting cauliflower seed crop.