Himachal Pradesh Krishi Vishva Vidyalaya College of Agriculture, Solan
Studies were conducted on the incidence and control of mustard aphids, Hyadaphis erysimi (Kalt) and Brevicoryne brassicae (L) vis-a-vis economics of different spray schedules on mustard. Behaviour of these aphids differs, as the former attacks the inflorescence the latter also the leaves. Population of B. brassicae and H. erysimi was in the ratio of 3:2 and that of the predators 3.3/plant. Methyl demeton, phosphamidon, dimethoate, methyl parathion and endosulfan were found effective in descending order on 3, 10, 15 and 30 days after treatment, however by the tenth day their effect was non significant when a repeat spray was given.
Two spray schedule was found to be superior to one because it covers the peak infestation period. It was also found economical as the net gain varied from Rs. 431/ha to Rs. 1657/ha against one spray schedule where the net gain was Rs. 143/ha to Rs. 411/ha.
