Biology of cabbage aphid under laboratory conditions

Biology of cabbage aphid,brevicoryne brassicae l. was studied on canola leaves under laboratory conditions at multan,pakistan. biological parameters were studied by feeding canola leaves to aphid in 50 ml capacity plastic vials. food was changed daily. aphid had a pre-reproductive and reproductive period of 2.34 and 6.25 days,respectively. number of nymphs produced per female was 30.79 and reproductive rate was 3.85 nymphs per female per day. longevity of reproductive females' was 9.0 days. nymphs completed three instars in 9.09 days. mean duration of first,second and third instar was 2.09,3.50 and 3.50 days,respectively. mortality of nymphs during development was 67.85,17.85 and 14.30 percent in first,second and third instar,respectively. out of the total nymphs produced 54.16% reached the reproductive stage. copyright 2011 zoological society of pakistan.