Producers must tailor products to the right beetle species for best results in canola, say scientists
Agriculture Canada and the crop protection industry are developing a plan to wean canola growers off neonicotinoid seed treatments.
Department experts met with industry representatives this winter to discuss seed treatments and how farmers can choose an insecticide that’s appropriate for the type of flea beetle in their canola fields.
Producers can now use only insecticidal seed treatments from the neonicotinoid family, sold under names such as Prosper and Helix, or a neonic seed treatment in combination with DuPont’s Lumiderm, a Group 28 chemistry classified as an anthranilic diamide.
However, Lumiderm isn’t available as a stand-alone seed treatment.
“Each product seems to have really strong points and a slightly weak side to them,” said John Gavloski, an entomologist with Manitoba Agriculture.
“What they (industry) have found is they make a good blend.”
Selling Lumiderm with a neonic seed treatment may be effective against flea beetles but coating every canola seed with a neonic will eventually lead to a rise in beetles with resistance to the insecticide, which is not good product stewardship.
“It would be nice to be able to rotate (chemistries) and not have to use a neonic every year,” Gavloski said.
Bob Elliott, an Agriculture Canada entomologist in Saskatoon and a flea beetle expert, said government and industry representatives are working on the problem.
The solution is more complex than using a diamide seed treatment one year and a neonic the next because two primary types of flea beetles feed on canola on the Prairies: crucifer and striped.
Crucifers used to dominate, but striped beetles are now more populous in many regions.
Agriculture Canada entomologist Julie Soroka said in a 2012 report that the striped flea beetle has displaced the crucifer “as the most frequently encountered flea beetle in central Alberta, central Saskatchewan and much of Manitoba. And once rarely encountered in the rape-canola fields of southern Canada, (the striped) is now found there in increasing numbers.”
The population shift is significant because neonics control crucifer flea beetles but are less effective against striped.
Lumiderm controls striped beetles but has its limitations.
“One of the things regarding some of the neonics is their water solubility…. If you get excess rain or moisture, you can see them wearing out early,” Gavloski said.
“Lumiderm, there’s less chance of that happening. But because it’s not as water-soluble, you may not get the really quick uptake.”
Elliott said it’s unlikely that a region or a canola field has one species and not the other. Many areas have both.
He said producers need to select a seed treatment suited for the type of flea beetles on their farm so that they’re not using a neonic on every canola seed, every year.
“The only way that can be done properly is for producers to begin to monitor those populations within their field … (particularly) the emergence of the summer generation of flea beetles that comes out in July, August and September.”
Elliott said farmers could use yellow, sticky traps to assess the spring and summer populations of flea beetles.
“Based on that information, a decision could be made to go with a neonic alone, diamide alone or a mixture of the two,” he said.