Selectivity of Some Newer Horticultural Mineral Oils and Some Insecticides on Parasitoid Complex of San Jose Scale (Quadraspidiotus perniciosus Comstock) on Apple in Kashmir

Field trials were conducted during 2004 to study the effectiveness of five horticultural mineral oils (HMOs) viz., D.C. tron plus (O₁), P.D. spray oil (O₂), H.P. spray oil (O₃), Atso spray oil (O₄) and Diesel oil (O₅) @ 2 per cent alone and in combination with five chemical insecticides, viz., endosulfan (C₁), ethion (C₂), Chlorpyrifos (C₃), dimethoate (C₄) and quinalphos (C₅) @ 0.05, 0.05, 0.021, 0.03 and 0.03 per cent, respectively against the San Jose scale (Quadraspidiotus perniciosus Comstock) on apple trees used as dormant spray. All treatments were observed effective against the pest but at the same time all treatments were evaluated for their impact on emergence of predominant parasitoids of San Jose scale (Encarsia perniciosus and Aphytis proclia). It was observed from the caged twig samples that all insecticides have more or less deleterious effect on the bio-agents. In oils alone highest population (3.66) of parasitoids were found associated with O₅ (Diesel oil) and lowest with O₁ (D.C. tron plus) 1.22 per cm² while in combination highest (2.55) emergence of parasitoids were found associated with O₂C₂ (P.D. spray oil + ethion) and lowest (0.11%) with O₁C₃ (D.C. tron plus + chloripyrifos). It was observed from the data that all oils were found safe to both the parasitoids with D.C. tron plus (O₁) slightly more toxic than other oils, while oil-chemical combination have deleterious effect on emergence of parasitoids.