There are three key insect pests of field crops for Manitoba farmers to keep an eye out for this year, says John Gavloski, extension entomologist with Manitoba Agriculture.
And the message you should walk away with, regardless of what crops you’re growing? Scout early, and scout often.
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While there are a number of types of flea beetles, Gavloski says a couple species have proven chronic pests of canola in the province over the past several years.
“Levels are high, and what compounds the problem: when you get growing conditions where it’s taking a long time for those seedlings to get three or four true leaves on them.”
While a seed treatment may be all you need in ideal spring conditions, Gavloski says there’s a big risk when these high populations couple with slow growing conditions.
“As soon as the crop comes up, you want to be checking for flea beetles and cutworms. And even if you’ve got an insecticide seed treatment on your canola (which it all does have) it’s still good to be out there looking. The cutworms can still be an issue, and it’s good to be keeping an eye on just how much feeding you’re getting.”
When it comes to cutworms, Gavloski says we’re not talking a particularly species, but “a complex of species.”
“So you’ve got different types of cutworms, and last year we had two species that were quite prevalent — one’s called dingy cutworm…the other one that we saw a lot of is called redbacked cutworm.”
But Manitoba has also started to see the pale western cutworm, which, in the past has been more prevalent in Alberta and Saskatchewan.
“We’ve had three dry summers in a row, and we were seeing some pale western last year, and where that’s a concern: they don’t come above ground much to feed like the other two cutworms, so when you have them as part of your mix they’re much harder to control with insecticides.”
While grasshopper populations will depend on the weather, Gavloski says 2018 and 2019 were both population-building years. Last year, some areas saw edge-spraying, and others even the whole spraying of fields.
And, fall moisture, and even early spring moisture are unlikely to impact populations much.
“So start scouting early, and again, the areas around your field — the headlands — start looking for grasshoppers in early June.”