Sask insect outlook: Wheat midge, grasshoppers

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Published: April 7, 2016

Winnipeg, April 7 (CNS Canada) – Based on surveys and last year’s conditions, one provincial specialist is naming several insect pests that Saskatchewan producers should watch out for this growing season.

WHEAT MIDGE

The biggest pest wheat producers face is wheat midge, said Scott Hartley, provincial specialist in insect and vertebrate pest management with the government of Saskatchewan.

Wheat midge. | File photo
Wheat midge. | File photo

Wheat midge is primarily an issue in eastern parts of Saskatchewan, mostly east-central and southeast, Hartley said.

“But some other patches of high population have shown up in a survey right through in the central area,” he said.

Prince Albert and north of Regina have also been flagged as areas with high wheat midge populations.

Since not all fields are sampled, there is the potential for wheat midge appear in other areas, Hartley added.

“We always have a bit of a disclaimer that it depends on the weather conditions, but climatic conditions can favour the midge,” he said.

Dry conditions are not favourable to wheat midge emergence.

Producers should watch for them while crops are heading and flowering.

CABBAGE SEEDPOD WEEVIL

“In canola the most common one we’re getting now is cabbage seedpod weevil,” Hartley said.

He added that the weevils are most commonly seen in southwest parts of Saskatchewan, but are expanding out of that region.

There are cabbage seedpod weevil populations east of Regina and near the Manitoba border.

Cold and wet spring conditions reduce the likelihood of a cabbage seedpod weevil infestation.

Producers can look for them with a sweep net during bud and flowering periods.

Weevil also use other crops in the mustard family as host plants.

FLEA BEETLES

Warm, dry conditions also favour canola-munching flea beetles.

“Last year with the conditions in the spring, we started to see a lot of flea beetle pressure,” Hartley said.

Flea beetle numbers were high going winter, so they could pose a problem this season once canola starts emerging.

Flea beetles overwinter and emerge in the spring.

GRASSHOPPERS

“Grasshopper populations aren’t expected to be very high, which is a bit of a surprise to me,” Hartley said.

Buildup populations of grasshoppers have been high the last few years.

But a survey done last year, which included observing adult populations and egg laying potential, showed that they could be less of an issue this season than in previous years.

But it only takes a small population of grasshoppers to pose an issue, Hartley said.

With some crops it only takes two per square metre to be a significant problem, he said.

The survey showed the highest numbers in northwest parts of the province, near Meadow Lake and Big River.

“I’ve seen this before, there’s certain species that have done well up there, so it could be a problem,” Hartley said.

SWEDE MIDGE AND DIAMONDBACK MOTH

Swede midge, a fly which eats canola and other crucifer crops and weeds, and the diamondback moth, which also feeds on canola and mustard, could pose an issue this year, but it’s still up in the air.

“The diamondback is an unknown one. We monitor over the summer because they get blown in,” Hartley said.

Swede midge is being monitored in Saskatoon. If they appear this year it will likely be in northeastern parts of the province, though they have been spotted across the northern wheat belt.

“Because of the quite mild winter … I kind of expect there to be some surprises with some of the insect populations out there,” Hartley said.

Other insects that could pose an issue this season include the alfalfa weevil, red turnip beetle and the wheat stem sawfly.

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