INSECT FAUNA DYNAMICS AND IMPACT OF BEE POLLINATION IN THE SANDBAR PUMPKIN PRODUCTION

Abstract

The experiment was carried out to explore the insect diversity of sandbar area of Tista River located at Gangachara upazilla in Rangpur district where pumpkin production has a great socio-economic impact on sandbar inhabitants. The investigation process was furnished by visual searching and sweeping net method during winter from January to April. Few species of insects found in the sandbar pumpkins. Aphid, red pumpkin beetle, truit fly and lady bird beetle were noticed during the cropping period. The number of aphids was the highest as compared to other species and no pollinator was observed. The extent of damage of pumpkins by the insects was observed during the period. Highest infestation (0.46 — 0.54%) on estimated leaves was infested in mid March to mid April while the lowest (0.02 — 0.03%) infestation occurred in January to February. The number of male flowers per plant was more than female flowers and the ranges of male flowers were 16 to 23 where the female flowers were 5 to 8 per plant. However, the fruit formation was higher in bee pollinated plant than hand pollinated plants. Bee pollinated plants produced 2 to 4 fruits per plant while hand pollinated plants produced 2 to 3 fruits. The number of pumpkin produced from bee pollinated plots ranges from 71 to 76 while it was 62 to 72 in hand pollinated plots. However, the bee pollinated plots showed the highest production of pumpkins (628.4 kg). On the contrary, the maximum yield was from the hand pollinated plots which was 579.1 kg.