Early season apple pest management: control of two species of scales (Homo: Diaspididae) and Bruce spanworm (Lep.: Geometridae) with methidathion

The organophosphate insecticide, methidathion, proved to be more efficacious for the control of San Jose scale (Quadraspidiotus perniciosus (Comstock)) and European fruit scale (Q. ostraeformis (Curtis)) than dormant oil when applied at the tight cluster stage of bud development. The compound also provided effective control of Bruce spanworm (Operophtera bruceata (Hulst)) and did not cause excessive mortality of the predaceous mites responsible for the biological control of orchard phytophagous mites. Methidathion use could be integrated into existing orchard pest management programs by using currently accepted sampling schemes for the above pest organisms to determine when thresholds requiring treatment have been exceeded.