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Mortality of Panonychus ulmi (Koch) susceptible and resistant to dicofol was measured in apple trees to estimate the selective effect of dicofol applications on mite populations. Mortality of P. ulmii from a susceptible (0% survivors in discriminating dose bioassay) and a resistant (70% survivors in discriminating dose bioassay) population were compared in a field bioassay. With conventional application procedures used in apple orchards, mites from the resistant population had 50% mortality; those from the susceptible population had 95% mortality. Frequencies of resistant phenotypes (RP) of P. ulmi were measured in five commercial orchards before and after treatment with dicofol, and one year after treatment. Frequencies before treatment averaged 7 and 3%, respectively, in dicofoltreated and untreated control plots. Two weeks after treatment, RP frequencies averaged 32%(dicofol) and 8%(control); 1 yr after treatment, RP frequencies were 41%(dicofol) and 14% (control). The measurements of selection resulting from single dicofol applications are discussed within the context of establishment of appropriate acaricide rotations for control of spider mites in New York apple orchards.
Document Type: Research Article
Publication date: February 1, 1991
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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.