The control of wireworms in Canada
By Top Crop Manager Staff
Lindane was one the most effective treatments for the control of wireworms. This active ingredient killed 65 to 70 per cent of the resident wireworm larvae and more than 85 per cent of new neonate larvae that were produced later in the season – knocking back populations for three years.
The neonicotinoid insecticides replaced lindane, but these active ingredients do not have the capacity to kill many resident larvae – allowing the larvae to recover fully by mid-summer. Then in early- to mid-summer, new neonate wireworms hatch and survive the treatment as well. This leaves large populations of wireworms in the field for the following season, and leads to an increase in wireworm populations over time.
Many Canadian farmers have noticed that wireworms have become much more prevalent since the loss of lindane. Why have U.S.-based producers not voiced similar concerns? The range of pest-management tools available to producers for the control of wireworms in field crops in the U.S., relative to their Canadian counterparts, may provide some insight.
Canadian producers have access to four active ingredients for the control of wireworms in a range of field crops; whereas U.S.-based farmers have access 22 active ingredients. Of the 18 active ingredients not available in Canada, the PMRA has:
- never registered seven,
- phased out the use of five,
- not registered use patterns for field crops for four,
- not registered any use pattern in any crops for one, and
- phased out the relevant use pattern for wireworm control for one.
Two of these 22 active ingredients include imidacloprid and lambda-cyhalothrin and two are, or will soon be, subject to re-evaluation. Should Canadian farmers lose any of the four active ingredients left for the control of wireworms, it may no longer be possible to control wireworms with any crop protection product in Canada.
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