Biology of cabbage aphid under laboratory condition in Nagaland

Abstract

A field experiment was carried out in the laboratory of Department of Entomology, School of Agricultural Sciences (SAS), Nagaland University, Medziphema campus during November, 2021 to March, 2022 to study biology of Brevicoryne brassicae on cabbage in laboratory condition. The duration of total nymphal period, pre-reproductive period, reproductive period, post-reproductive period, adult longetivity and total life span was 10.00±0.28, 2.00±0.34, 17.70±3.34, 2.70±1.40, 27±3.91 and 35.5±5.38 days, respectively. Number of nymphs produced per female was 69.65±1.18 and reproductive rate was 3.00±0.98 nymphs per female per day. Mean duration of first, second, third and fourth instar of nymph were 2.00±0.37, 3.00±0.29, 3.00±0.43 and 3.00±0.12 days, respectively. The morphometry studies of B. brassicae revealed that there was a progressive increase in size of the body. The 1st, 2nd , 3 rd and 4th instar of nymphal were measured from 0.658, 1.095, 1.537 and 1.985 mm, respectively. The total length of the antennae of 1st, 2nd, 3rd, and 4th, nymphal instar were 0.401, 0.687, 0.989 and 1.293 mm, respectively. The apterous adult are dark-greyish green in colour with a body length of 2.31 mm and a width of 1.56 mm. The length of antennal segment III, VI and total antennae were 0.431 mm, 0.565 mm, and 1.75 mm, respectively. Length of Untimate Rostral Segment (URS) in adult stage is 0.129 mm and hind tarsal segment 2 is found to be 0.126 mm.