PLANTING DATES AND VARIETIES VS. CABBAGE APHID, BREVICORYNE BRASSICAE

摘要

A study was carried out in the Entomological Research Farm, SASRD, Nagaland University during rabi, 2010-2011. Results showed that planting dates has significant influence on the aphid population with the peak population from 30 DAP to 75 DAP (days after planting), during December to mid-February. Maximum population (8.10 aphids/leaf) was recorded at 30 DAP and minimum (2.32 aphid/ leaf) at 90 DAP on 15"' December planting. Out of the five varieties tested, maximum population was recorded on G-8 variety (8.83 aphids/leaf) and least on the cultivar Rare Ball (5.26 aphids/leaf). Overall, late planted crop of 15>h December harboured less population and variety Rare Ball planted on 30,b November was found most ideal in Nagaland condition.