Experiments were conducted in 1980 and 1981 at Arlington and Hancock, Wis., to develop action threshold levels (ATL) for Empoasca fabae (Harris) on potatoes in Wisconsin. Various levels of adult and nymphal densities were achieved with different treatments of fenvalerate, and subsequent effects on yield were determined. In 1980, when adults migrated into the state in relatively small numbers, the appropriate ATL was 25 adults per 25 sweeps when nymphal densities exceeded ca. 20 per 25 leaves. In 1981, adults entered the state in large numbers and the appropriate ATL was 100 adults per 25 sweeps when nymphal populations were .≤10 per 25 leaves. A dynamic action threshold model was developed by regressing the maximum number of adults attained without causing significant yield reductions in 1980 and 1981 against the nymphal population at various adult densities. This model describes a population of adults and nymphs with a single value, and is dependent on the age structure of the potato leafhopper population. The age structure is, in turn, largely determined by the size of influxes of adults.
Document Type: Research Article
Publication date: October 1, 1984
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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.