NOTES ON THE HABITS OF THE SAN JOSE SCALE AND THE EUROPEAN FRUIT SCALE (HOMOPTERA: DIASPIDIDAE) ON HARVESTED APPLES IN BRITISH COLUMBIA

Abstract

The habits of the San José scale, Aspidiotus perniciosus Comstock, and the European fruit scale, A. ostreaeformis Curtis, on harvested apples in British Columbia are discussed under the following topics: stages found on apples; distribution and mortality on apples; influence on size, odor, and skin of apples; discoloration of fruit; and appearance of scales on apples. Outstanding characteristics of the San José scale are: all stages occur on the fruit; crawlers settle primarily in the stem end of Newtown and Winesap apples, equally in the stem and calyx ends of Rome Beauty, and predominantly in the calyx end of Delicious; the scale survives longer in the stem end than in the calyx end of stored Newtown, Winesap, and Delicious apples; all scales eventually die in storage; and infestations decrease the size of apples, adversely affect color and maturity, impart a moldy odor to the fruit, and mark the skin of all varieties by causing red spots around the scales. Comparable habits of the European fruit scale are: males and females do not occur on the fruit; more crawlers settle in the stem end of Newtown, McIntosh, and Hyslop crab apples than in the calyx end but the reverse distribution occurs on Rome Beauty; the scale survives longer in the calyx end of all varieties; all scales do not die on apples placed in storage; infestations apparently do not affect size, color, maturity, and odor of fruit; and feeding of the scale seldom marks the skin of Newtown apples but it does cause purplish-red spots around the scales of all other varieties of apples.