Evaluation of biorationals in management of chrysanthemum aphid, Macrosiphoniella sanbornii (Gillette)

Nymphs and adults of chrysanthemum aphid Macrosiphoniella sanbornii (Gillette) colonize on under-surface of leaves, apical shoots, buds and flowers. They suck sap resulting in devitalization of affected parts. In order to find out the relative efficacy of different biorationals/insecticides like azadirachtin @ 5 ml/l, karanj oil @ 2 ml/l, Verticillium @ 5 g/l, Verticillium @ 5 g/l followed by azadirachtin @ 5 ml/l, Verticillium @ 5 g/l followed by karanj oil @ 2 ml and imidacloprid @ 0.4 ml/l two sprays at ten days interval were applied. Field experiment was conducted at Floriculture Research Station, Rajendranagar, Hyderabad. The insecticides were evaluated on the basis of reduction in population over control at 1, 3, 5, 7 and 10 days after spraying (DAS). Among treatments imidacloprid was the most effective treatment in reducing aphid population by 92.31 per cent which was a significant reduction over untreated control as compared to the other treatments. The next effective treatments were Verticillium followed by azadirachtin (68.54%), two sprays of azadirachtin (68.49%) and Verticillium followed by karanj oil (67.34%) which were all significantly different from each other. Two sprays of Verticillium were found to significantly reduce aphid population over control but was least effective (64.66%) in comparison to rest of the treatments.