Grasshoppers are prevalent in southern Vulcan County, northwest Lethbridge County and in Willow Creek (Pexels)

By Justin Goulet

Plenty of Pests

Beware of pests: expert weighs in on what insects can be found in southern Alberta

May 21, 2019 | 11:19 AM

LETHBRIDGE, AB – Pests can be a nightmare for landowners, and there are certain types people in southern Alberta should be on the lookout for.

Scott Meers is an Insect Management Specialist with Alberta Agriculture and Forestry.

He said right now and going into the summer, farmers and agronomists should be on the lookout for cutworms, “virtually on all crops.”

“We haven’t had a lot of issues so far with cutworms, but it’s the time of year to be watching for them,” Meers told Lethbridge News Now.

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“The other thing right now would be flea beetles in canola. In the past couple of years, we’ve had a bit more flea beetle issues in southern Alberta.”

Cut worms hide under soil or litter during the day and come out at night to feed on plants. They tend to start at the first part of the plant they encounter, usually the stem and proceed to ‘cut’ up the rest of the plant, hence their name.

Flea beetles feed on plants of the mustard family that grow across Canada and the Northern Great Plains of North America, according to the Canola Council of Canada.

Eight flea beetles species have been known to attack mustard, rapeseed and canola.

Meers added that as the season moves along, producers might notice pea leaf weevil as well.

“We’re not sure what the population’s doing right now, it’s been down the last couple of years, so we’ll see what comes later this year. Later into the summer, (we have issued with) cabbage seedpod weevil in canola every year,” he said.

Pea leaf weevil feed on the roots (as larvae) and leaves (as adults) of a variety of cultivated and wild legume species. According to provincial government records, the pea leaf weevil is native to Europe and the first case of the insect attacking peas in Alberta was near Lethbridge in 2000.

Cabbage seedpod weevil is found primarily south of the TransCanada highway in Alberta and continues to travel into Saskatchewan south of the South Saskatchewan River.

GRASSHOPPERS

Meers said they’re expecting a resurgence of grasshoppers later in the spring and summer.

“The worst areas from our surveys are the southern Vulcan County and northwest part of Lethbridge County, then over into Willow Creek seem to be where the grasshoppers were building up the most.”

He added that throughout the southern region of the province, specialists are also seeing wheat stem sawfly with the drier weather in the area the last few years.

Wheat stem sawfly is found in the brown soil zone of the Great Plains, attacking wheat and barley crops.

Provincial data shows that increased levels of sawfly damages were found in Vulcan, Foothills and Newell. The M.D. of Acadia, Special Areas 3 and Forty Mile County all experienced an increase in wheat stem sawfly populations in 2018.

PREVENTION

“Preventative (measures are) pretty tough. For the wheat stem sawfly, we do have solid stem wheat that we’re recommending producers in some areas use. For some of the others, it’s ‘scout and react’ if necessary, for all the rest,” Meers said.

Solid stem wheat doesn’t allow sawflies room to grow after they hatch and, in some cases, crush the eggs before they actually hatch.

“Each (invasive species) has their seasonality. We’ll be seeing pea leaf weevil, flea beetles and cutworms right about now. That’s kind of what we’re looking at for potential right away,” _{– Scott Meers, Insect Management Specialist}

“Another thing (for prevention) is just get out and check the field, see what’s happening in the fields. If there’s issues, then that’s how you pick them up. Make footprints in your field is what we like to say.”

DAMAGES

Insects can be very damaging to crops and field vegetation, according to Meers.

“Usually you pick up cutworms by noticing a plant that has wilted or dried up, and then you’d dig around and see if there’s a cut-off and that’s the reason it’s died,” he said.

“Pea leaf weevil looks like somebody took a hole punch and punched out the edge of the leaf, that’s a pretty distinctive feeding pattern. Grasshoppers just disappear in crops, I guess, with lots of little hoppers jumping around.”

Meers added that later in the season, cabbage seedpod weevil can be difficult to spot because damage is located inside the pod of the canola, but he recommends sweeping at samples for monitoring.

“Wheat stem sawfly is also inside the stem so the only way to know if you’ve got wheat stem sawfly is to actually take wheat stem after the heads start forming and split them open to see if they’re inside there. You also know it’s the season because sawfly cut the wheat and that falls over, that’s often the first indication, unless you’ve been watching otherwise.”

He said flea beetles usually leave little “shot holes” on leaves, and every species has its own unique sign that people can watch out for.

Residents can visit the Alberta Insect Pest Monitoring website to view a map of areas that will see potential infestations, and further details on each species.