title: Fecundity in twospotted spider mite (Acari: Tetranychidae) is increased by direct and systemic exposure to imidacloprid.
abstract: 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.
authors.affiliation: Department of Entomology, Washington State University, Irrigated Agriculture Research and Extension Center, Prosser 99350, USA. djames@tricky.wsu.edu
authors.forename: David G
authors.initials: DG
authors.lastname: James
authors.forename: Tanya S
authors.initials: TS
authors.lastname: Price
mesh_terms: D000818:Animals; D005260:Female; D005298:Fertility / Q000187:drug effects; D007093:Imidazoles / Q000494:pharmacology*; D007306:Insecticides / Q000494:pharmacology*; D008925:Mites / Q000187:drug effects* / Q000502:physiology; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010058:Oviposition / Q000187:drug effects; D010944:Plants
chemical_list: D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; C082359:imidacloprid