Studies on the Efficacy and Economics of Sprays of Synthetic Pyrethrows Against Mustard Aphid, Lip Aphis Erysimi (Kalt) On Rape Seed.
Two field experiments were conducted during 1983–85 at Hissar (Haryana) to compare the efficacy of four synthetic pyrethroids - permethrin (100 g/ha), cypermethrin (100 g/ha), decame-thrin (28 g/ha) and fenvalerate (100 g/ha) with the organophosphorus insecticide oxy-demeton methyl (250 and 500 g/ha) on mustard for the control of the aphid, Lipaphis eyrsimi (Kalt.). Based on counts at 3,7 and 15 days after spray, the synthetic pyrethroids, especially fenvalerate and decamethrin gave good control of the aphid, comparable, to oxy-demeton methyl. However, at 20 days after spray considerable aphid build up occurred only in plots sprayed with the synthetic pyrethroids. Based on the overall seed yield and the cost of spraying the insecticides, it was found that the synthetic pyrethroids had narrower cost: benefit ratios than oxy-demeton methyl.