Reissig, W.H., Weires, R.W., Onstad, D.W., Stanley, B.H., & Stanley, D.M. 1985 Timing and effectiveness of insecticide treatments against the San Jose scale (Homoptera: Diaspididae).. Journal of Economic Entomology 78: 238-248.

Notes: Evaluation of single dilute sprays of various types of petroleum oil alone, methidathion or chlorpyrifos alone, or combinations of oil with the two insecticides applied at the half inch green growth stage were all highly effective against overwintering populations of the apple pest Quadraspidiotus perniciosus in New York state.