Differences in Phyllotreta cruciferae and Phyllotreta striolata (Coleoptera: Chrysomelidae) responses to neonicotinoid seed treatments

• Author(s) / Creator(s)

  • Keddie, B. A.
  • Sarfraz, R. M.
  • Tansey, J. A.
  • Dosdall, L. M.

• Abstract: Insecticidal seed treatments are used commonly throughout the Northern Great Plains of North America to systemically protect seedlings of canola (Brassica napus L. and Brassica rapa L.) from attack by the flea beetles Phyllotreta cruciferae (Goeze) and Phyllotreta striolata (F.) (Coleoptera: Chrysomelidae). Here, we investigated differential responses by the two flea beetle species to the neonicotinoid seed treatments thiamethoxam (Helix and Helix XTra) and clothianidin (Prosper 400) in greenhouse experiments. P. cruciferae experienced higher mortality and fed less when exposed to these compounds than did P. striolata. Beetles of the overwintered and the summer generations responded differently when feeding on seedlings that developed with insecticidal seed treatments, with mortality higher for P. cruciferae in May than in August. When the two flea beetle species were held together at equal densities and allowed to feed on seedlings affected by the seed treatments, mortality of P. cruciferae significantly exceeded that of P. striolata. Differences in efficacies of these compounds for these beetles have ramifications for management strategies in regions where these insects occur sympatrically. Competitive release of P. striolata was previously reported to occur when P. cruciferae was excluded from brassicaceous crops; consequently, the consistent use of these seed treatments over millions of hectares of canola cropland may be a factor that contributes to a shift in prevalence of flea beetle pest species from P. cruciferae toward P. striolata.

• Date created

  2008

• Subjects / Keywords

  • Canola
  • Neonicotinoid
  • Flea beetles
  • Seed treatment
  • Species composition shift

• Type of Item

  Article (Published)

• DOI

  https://doi.org/10.7939/R3M61BS86

• License

  © 2008 Entomological Society of America. This article is the copyright property of the Entomological Society of America and may not be used for any commercial or other private purpose without specific written permission of the Entomological Society of America.