ABSTRACT
Pinnock, Dudley E., Richard J. Brand, James E. Milstead, and Nancy F. Coe. 1975. Suppression of populations of Aphis gossypii and A. spiraecola by soap sprays. Journal of Economic Entomology 67(6):
An integrated control program for highway landscape pests is under development in California. Among the pest species in the landscape system are the stem-feeding aphids, Aphis gossypii Glover and A. spiraecola Patch, which occur in very large numbers on various flowering shrubs, particularly Pyracantha varieties. Formerly, the shrubs were treated with organophosphate insecticides to control early outbreaks of these aphids. This treatment, while effective in temporarily suppressing the aphid populations, kills parasitoids and predators of both the aphid species and the redhumped caterpillar, Schizura concinna (J.E. Smith), another important pest in the highway landscape. Soap sprays have been a traditional means of aphid suppression for over a century and are considerably less toxic to insects than organophosphate insecticides. Thus it seemed possible that a dilute soap spray could provide the required suppression of the aphids and probably cause less mortality among the parasitoids and predators than would the newer insecticides, thus permitting more effective long-term biological control. A specially formulated soap spray was effective for removal of Aphis gossypii and A. spiraecola on highway plantings of Pyracantha in California. Water alone produced a removal rate of 46-47% for both species, and a general pattern of increased removal rate with higher concentrations of the soap solution was noted. The maximum soap concentration tested, 0.1 %, produced removal rates of 72 and 79% for A spiraecola and A. gossypii, respectively.
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