author(s)
Daizy Sarma, DK Saikia and A Devee

abstract
A field experiment was conducted in the Experimental farm, Department of Horticulture, Assam Agricultural University, Jorhat during rabi 2014-15 & 2015-16, respectively to study the effect of different intercrops and border crops against major insect pests and natural enemies of cabbage. The treatments were cabbage intercropped with mustard and cowpea (T₁), cabbage intercropped with mustard and oats as border crop (T₂), cabbage intercropped with cowpea and oats as border crop (T₃), oats as border crop (T₄) and cabbage as sole crop (T₅). Major insect pests recorded during the crop season were diamondback moth, Plutella xylostella (L.), cutworm, Agrotis ipsilon (Hfn.) and flea beetle, Monolepta signata Oliv. The predators were viz., Coccinella transversalis (F.) and syrphid fly, Episyrphus belteotus. Plutella xylostella showed the highest occurrence followed by Agrotis ipsilon. Out of the five treatments, the pooled data revealed that T₁ was found to be more effective treatment in reducing DBM, cutworm and flea beetle (1.25,1.22 and 1.01) / plant, followed by T₃ (1.50,1.44 and 1.19) / plant. The highest population of coccinellid and syrphid was observed in T₁ (3.71, 2.88) / plant followed by T₃ (3.29 and 2.55) /plant, respectively. In case of insect pests as well as predators a significant difference was observed among all the treatments. The maximum yield was observed in T₁ with 212.78q/ha followed by T₃ with 205.28q/ha.