2013 crops | Specialist says problematic pests will include bertha armyworms, flea beetles and cabbage seedpod weevils
Potential insect threats in Alberta this year include bertha armyworms, wheat midge, flea beetles and the evil weevils — cabbage seedpod and pea leaf.
Scott Meers, insect management specialist with Alberta Agriculture, gave his pest predictions at the Jan. 16 agronomy update in Lethbridge, along with an assessment of 2012 insect problems.
Meers said 200,000 acres were sprayed for bertha armyworms last year, primarily in east-central Alberta. Hot spots were reported in the counties of Vulcan and Wheatland, which could be a harbinger of infestation this year.
However, he estimated 30 to 40 percent of the worms were killed by parasitic flies and wasps, as well as by viral disease.
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The northeastern and southern regions are the most likely to see bertha problems this year.
He said bertha damage in corn crops in the Viking region last summer illustrated the importance of weed control in suppressing insects.
“They were doing significant damage to the crop. Why was that going on? If you looked underneath the canopy of the corn, there was solid growth of lamb’s quarters.”
The weeds are a preferred food for armyworms, but the insects will move to crops when the weeds are gone.
“In agriculture, everything we do is connected, so when we do our weed control, it might have impacts on your insect season.”
Wheat midge was found in all 61 wheat-growing counties in 2012, indicating potential problems this year.
“We are finding wheat midge throughout the province … and we are finding it in fairly high numbers in southern Alberta. In fact, more in southern Alberta than in central Alberta, which is a little bit contradictory.”
The insect is usually a bigger problem in central regions, but it reached problem levels in Willow Creek, Lethbridge, Vulcan, Wheatland and Rockyview last year.
“It’s time to pay attention to it,” said Meers.
The coming season could also bring flea beetle issues. Meers said he received many reports from across the province last fall of plentiful beetles during swathing.
“If you are seeing high numbers of flea beetles while you’re swathing, that’s your warning for next year because those overwintering flea beetles are the ones that attack your seedlings next year, so pay attention to that.”
High levels of pea leaf weevil are expected this year, particularly south of the Trans-Canada Highway and in all counties that touch it.
Meers said farmers who intend to plant peas should consider seed treatment because populations are high and a warm spring could worsen the problem.
Seed treatment may be better than foliar spraying, he added.
“We are not getting good control of this problem. We are not getting yield response from using a foliar application of insecticide,” he said.
“It might make you feel good because you do kill the weevils, but you don’t get the yield response because the weevils have probably already laid their eggs.”
As for the other evil weevil, Meers encouraged growers to scout canola crops for cabbage seedpod weevil, which is also expected to be a problem south and surrounding Highway 1.
He said the insect seems to be extending its reach, and growers north of the highway should scout and consider how they plan to control outbreaks.
Diamondback moths, wheat stem sawfly and grasshoppers are not expected to present major problems this year.
