ROLE OF INSECT POLLINATOR ON CUCUMBER (CUCUMIS SATIVUS L.) YIELD

Abstract

Foraging activities of insect visitors were studied on cucumber (Cucumis sativus L.). The insect visitors in decreasing order of abundance were Formica sp. >Apis mellifera >Halictus sp. > Apis cerana>syrphids. The activity of insects was peaked between 08.00-09.00 followed by 11.00-12.00 and 14.00-15.00 hours. The foraging behaviour of A. mellifera and Halictus sp. was studied. The bees spent significantly more time per flower during morning hours (sec/flower) and foraged significantly fewer flowers (7.9 flowers/min) compared to evening hours. There were significantly more nectar foragers (6.03/m²/10 min) than pollen foragers (5.16/m²/10 min). Most pollen foragers were observed during morning hours (6.59/m²/10 min) whereas nectar foragers were most active during noon hours (6.63/m²/10 min). Significant increase in fruit set was observed; highest being in hand pollination (70.68%) followed by open pollination (61.92%) and without honey bee pollination (48.96%). Percentage of misshapen fruits was maximum in without honey bee pollination (24.35%) followed by open pollination (20.25%) and hand pollination (14.1%). Without honey bee pollination resulted in significantly lowest percentage of healthy fruits (75.25%) as compared to hand (85.50%) and open pollination (79.64%). Similarly weight of fruits (770.51 g), number of seeds per fruit (390.56), fruit diameter (23.9 cm), fruit length (21.8 cm) and weight of 1000-seeds (23.14 g) was lowest in honey bee pollination as compared to hand pollination which was highest among the three form of pollination and that was fruits (985.13 g), number of seeds per fruit (425.22), fruit diameter (27.1 cm), fruit length (26.7 cm) and weight of 1000-seeds (28.64 g).