The effect of imidacloprid on fecundity in twospotted spider mites, Tetranychus urticae Koch, was investigated in laboratory experiments using individual females on bean leaf discs. Mites were directly exposed to spray formulations of imidacloprid or fed on discs cut from a systemically treated bean plant. Imidacloprid-treated T. urticae produced 10–26% more eggs during the first 12 d of adult life and 19–23% more during adulthood compared with a water-only treatment. Increased egg production occurred immediately after exposure and lasted for about 15 d in sprayed mites. In mites exposed to imidacloprid by ingestion, increased egg production was not apparent until after 6 d and lasted until about day 18. Longevity was significantly greater in mites that ingested imidacloprid but not in sprayed mites. The significance and importance of imidacloprid-stimulation of fecundity in T. urticae to pest management in crop systems like hops, which routinely use this insecticide, is discussed.
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.