In British Columbia parathion was first officially recommended to the fruit grower in 1949 for the control of orchard insects and mites, particularly the pear psylla, Psylla pyricola Foerst.; the European red mite, Metatetranychus ulmi (Koch)=[Paratetranychus pilosus (C. & F.)]; and the Pacific mite, Tetranychus pacificus McG. Similar recommendations were made simultaneously in other Canadian fruit-growing areas. In British Columbia the Okanagan Spray Committee advised the use of only one formulation and one concentration: 15 per cent wettable powder at 0.75 pounds per 100 imperial gallons. At the start of the season most growers were rather reluctant to use parathion, not necessarily because it was new but because the poisonous nature of the material had been so thoroughly impressed upon them. However, as the season progressed and orchard pests became generally more troublesome, their attitude changed, so that by mid-season the use of parathion was common. It is estimated that at least 75 per cent of Okanagan Valley fruit growers used this insecticide at one time or another during the season. They bought from 40 to 50 tons of 15 per cent parathion wettable powder in 1949.