Flea beetle (Phyllotreta spp.) management in spring-planted canola (Brassica napus L.) on the northern Great Plains of North America

Canola (Brassica napus L. and B. rapa L. [Brassicales: Brassicaceae]) is a major oilseed crop grown globally as a source of vegetable oil, animal feed and biofuel feedstock. The global demand for canola oil as a biofuel feedstock has increased due to recent regulations in the European Union, United States, and Canada. In North America, canola production is centered on the northern Great Plains where it is challenged by two highly destructive flea beetle species, the crucifer (Phyllotreta cruciferae Goeze, 1777) and the striped (Phyllotreta striolata Fabricius, 1803) flea beetles. In the spring, adult P. cruciferae and P. striolata begin feeding on canola seedlings, creating a ‘shot hole’ appearance, which can reduce the plant's photosynthetic capacity leading to uneven plant emergence and growth, reduced plant stand density, and reduced seed yield. Losses resulting from flea beetles are estimated in the tens of millions of dollars annually. At present, the principle means for flea beetle control are insecticides applied as systemic seed treatments and/or subsequent foliar sprays. The continued use of these products is being questioned due to environmental concerns and acquisition of resistance. As such, significant research effort is being directed toward the development of an integrated pest management system for these abundant and hard to manage pests of canola. Here, we review the ecology, pest status, and management of flea beetles in North America and discuss future research needed to promote flea beetle management and sustainable canola production.