Effect of azadirachtin applied systemically through roots of plants on the mortality, development and fecundity of the cabbage aphid (Brevicoryne brassicae)

The effect of low concentrations of azadirachtin applied systemically through root tissues of rape plants (Brassica napus subsp.napus) on the mortality, period of development, longevity and fecundity of the cabbage aphid (Brevicoryne brassicae L.) (Sternorrhyncha: Aphididae) was studied. The concentrations of azadirachtin A tested were: 0.25, 0.05, 0.005, 0.0005 and 0.00005 mg ml−1. The mortality of cabbage aphid nymphs, particularly during the period of ecdysis, increased significantly with increasing concentrations. Azadirachtin had no effect on the length of the development period of the respective immature stages of cabbage aphids. The average longevity of the cabbage aphids decreased with increasing azadirachtin concentration and time spent feeding. The fecundity of aphids decreased after the application of azadirachtin.