Project Code: MUR07-040
Robert Vernon - Agriculture and Agri-Food Canada
To study repellency and toxicity of various insecticides to wireworms and to evaluate efficacy of promising insecticidal blends in potato and wheat fields; and to map wireworm pest species on a national basis
Summary of Results - national species distribution map
Wireworms are the larval stage of click beetles. More than 800 species are known worldwide and approximately 30 species are recognised as pests in Canada. They are a problem in many crops, especially potatoes and other such vegetables as corn, cereals, canola, and pulses.
The increase in wireworm populations is likely due to the removal of organochlorine insecticides (that is aldrin, dieldrin and heptachlor) in the 1960s and 70s. In potatoes, the only products currently registered that will reduce wireworm levels and protect daughter tubers at harvest are Thimet 15G (phorate) and Pyrinex 480EC (chlorpyrifos). Thimet is scheduled to be de-registered in 2012. Due to trade barriers, the use of Pyrinex is limited to potatoes designated for the domestic market (no Maximum Residue Limit (MRL) for chlorpyrifos-treated potatoes in the United States (U.S.)).
Agriculture and Agri-Food Canada (AAFC) conducted insecticide screening trials in potatoes to identify low-risk candidates for wireworm control. As the efficacy of certain classes of insecticides (that is neonicotinoids, synthetic pyrethroids) has been shown to vary with differing wireworm species, it created the need in a national survey to determine the predominant wireworm species in key agricultural areas across Canada.
Wireworms were collected from sites across Canada through collaboration between AAFC, growers, and crop specialists. In a series of seminars given in seven provinces during 2007 and 2008 by the Project Lead, R. Vernon, growers and extension professionals have been asked to collect specimens whenever found and send them for identification. All field material was sent to AAFC-Agassiz, British Columbia (BC), and samples have been identified by Wim van Herk. The current version of the wireworm distribution map is comprised of 3-year survey data, 2007-2009.
The national distribution map documents over twenty wireworm species and demonstrates differences in the species composition between major productions regions in Canada. Among the noticeable differences are Agriotes lineatus, a species found in BC and in Atlantic Canada but not in Ontario or the prairies; Agriotes sputator, a species found only in the Atlantic Provinces (Nova Scotia (NS), Prince Edward Island (PEI)); and Limonius canus, a species found only in BC.
The wireworm species distribution map will serve growers and crop specialists alike when choosing the most appropriate pest management tools to be used on a regional basis. It will enable growers to avoid using insecticides known to have reduced efficacy on certain wireworm species in production areas where these species are dominant. It is expected that the survey will continue in the coming years and new, updated versions of the map will be published as they become available.
This study was funded by AAFC's Pest Management Centre.