title: Susceptibility of Aphelinus certus to foliar-applied insecticides currently or potentially registered for soybean aphid control.
abstract: BACKGROUND
  Soybean aphid, a serious economic pest of soybean in North America, is currently managed by applying non-selective foliar insecticides during outbreaks according to decision thresholds and crop maturity. Natural enemies, such as the parasitoid Aphelinus certus Yasnosh, potentially play an important role in suppressing soybean aphid. Using selective insecticides that preserve A. certus may enhance the biological control service they provide and thus prevent or reduce the severity of soybean aphid outbreaks. The toxicity of five insecticides (λ-cyhalothrin, dimethoate, flonicamid, mineral oil, spirotetramat) and the biopesticide Beauveria bassiana to A. certus was assessed.
  
  
  RESULTS
  The LD50 values of λ-cyhalothrin and dimethoate were similar; however, the hazard quotient of dimethoate was greater than that of λ-cyhalothrin. In a screening bioassay, the descending order of toxicity for the recommended rates 48 h after application was dimethoate>λ-cyhalothrin>flonicamid>mineral oil>Beauveria bassiana>spirotetramat.
  
  
  CONCLUSIONS
  Overall, λ-cyhalothrin and dimethoate were both harmful to A. certus. The other insecticides tested were harmless to A. certus and are potential candidates for inclusion in soybean aphid management programs.
authors.affiliation: School of Environmental Sciences, University of Guelph, Guelph, ON, Canada.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Frewin
authors.forename: Arthur W
authors.initials: AW
authors.lastname: Schaafsma
authors.forename: Rebecca H
authors.initials: RH
authors.lastname: Hallett
mesh_terms: D000818:Animals; D001042:Aphids / Q000469:parasitology*; D007306:Insecticides; D007928:Lethal Dose 50; D010572:Pest Control, Biological; D013025:Glycine max / Q000469:parasitology; D014863:Wasps
chemical_list: D007306:Insecticides