Apple, San Jose Scale Control, 1978

Insecticides with and without superior oil were evaluated for control of San Jose scale. The sprays were applied to runoff to single-tree plots in a randomized block design consisting of 4 replicates of Stayman Winesap apple trees. The trees were heavily infested with San Jose scale. The materialswere applied with aspraygunfrom a truck-mounted John Bean sprayer equipped with a 25 gpm pump. A general purpose spray of 0.5 lb Guthion 50W/acre was applied with an airblast sprayer at 50gal water/acre to the whole block atca. 3-wk intervals. Effectiveness of the materials was evaluated by counting the number of live scales on 4 four-inch sections of new growth/replicate from the top part of the trees. Numbersof livescaleupto 100 scale/twig were counted. Fruit evaluations consisted of examining 50 apples/replicate on Aug 17 and 100 apples/replicate on Oct 11. Number of scale marks up to 100 scale/apple were counted.