EFFECT OF INTERCROPPING ON THE INSECT PEST INFESTATION AND THEIR NATURAL ENEMIES OF CABBAGE

Abstract

A field experiment was carried out at research farm of Sher-e-Bangla Agricultural University to find out the effect of intercropping on the insect pest infestation of cabbage. The crop combinations were cabbage ± garlic, cabbage + radhuni. cabbage + mouri, cabbage + methi. cabbage + kalizira, cabbage + coriander. cabbage + onion and sole cabbage. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications. The lowest number of insect pest (0.03. 0.12, 0.32, 0.60,1.20, 1.59, 2.15, 2.41 and 3.00 at 15, 22, 29. 36, 43, 50, 57. 64 and 71 DAT, respectively) and highest infestation reduction over control (97.89, 92.281 83.08, 75.68, 66.40, 62.61, 56.20, 54.75 and 55.40 at 15, 22, 29, 36, 43, 50. 57, 64 and 71 DAT, respectively), The highest number of natural enemy (0.98, 1.41. 1.75 and 2.18 at 50, 57. 64 and 71 DAT, respectively), lowest number of insect pest family (2.21) and highest reduction over control (69.07%). The highest number of natural enemies (2.85) and The highest increase over control (64.29%) were achieved by Cabbage + garlic intercropping system. The highest cabbage yield (63.29 riha). relative yield (1.08 t/ha) and cabbage equivalent yield (63.50 t/ha) were obtained in Cabbage + garlic intercropping system. The highest gross return (Tk. 305160.00/ha) was recorded from the Cabbage + garlic intercropping system. Considering the results of the present study, cabbage + garlic intercropping system showed the best performance in respect of reducing insect pest and increasing natural enemies, relative yield, cabbage equivalent yield and gross return.