Four oils of different properties were evaluated for the control of the pear psylla, psylla pyricola Foerster, on Bartlett pears in British Columbia. A "superior type" oil, applied either alone or in combination with azinphosmethyl during the foliage season gave good control. Two oils of low viscosity (58.4, 58.5 S.S.V.) were compared with an oil of high viscosity (147 S.S.V.) as delayed dormant sprays in April and as foliar sprays in June. The low-viscosity oils gave poor control of the pear psylla adults, while the high-viscosity oil provided good control. There was little difference between the oils in their effect upon the nymphal stages, but owing to lack of adult kill, trees sprayed with the lighter oils were quickly reinfested. The heavier oil provided control for 6 weeks during the foliage season. The lighter oils were phytotoxic to pear leaves, causing marginal burn and necrotic spots. The heavy oil did not cause any significant injury. Analysis of oil deposits on the foliage showed that the superior type oil and the high-viscosity oil persisted for 28 days. The low-viscosity oils dissipated rapidly; 50% of the initial deposit was lost in 7 days.
Document Type: Research Article
Publication date: February 1, 1967
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Journal of Economic Entomology is published bimonthly in February, April, June, August, October, and December. The journal publishes articles on the economic significance of insects and is divided into the following sections: apiculture & social insects; arthropods in relation to plant disease; forum; insecticide resistance and resistance management; ecotoxicology; biological and microbial control; ecology and behavior; sampling and biostatistics; household and structural insects; medical entomology; molecular entomology; veterinary entomology; forest entomology; horticultural entomology; field and forage crops, and small grains; stored-product; commodity treatment and quarantine entomology; and plant resistance. In addition to research papers, Journal of Economic Entomology publishes Letters to the Editor, interpretive articles in a Forum section, Short Communications, Rapid Communications, and Book Reviews.