Alberta’s annual insect forecasts show few worrisome areas, with one notable exception
Alberta farmers may have fewer issues with cabbage seedpod weevil this year, except for those near Foremost.
Grasshopper forecasts also indicate limited threat, except for those near Foremost.
And as for wheat stem sawfly? Yes, Foremost could see greater numbers.
The County of Forty Mile in southeastern Alberta has potential to be the insect hot spot this summer, according to forecasts from provincial entomologist Scott Meers.
He gave a summary of 2014 insect problems and predictions for the coming crop year during the Jan. 20-21 agronomy update in Lethbridge.
Alberta Agriculture specialists monitor seven insects, assisted by agricultural fieldmen, agronomists and researchers. Surveys are designed to enable early warning of potential problems.
Cabbage seedpod weevil, a perennial pest in southern Alberta that has steadily spread northward, is likely to be a problem south and east of Calgary and in the deep south-central region. A hot spot north of Medicine Hat is also possible.
“They’re not hard to deal with. It’s pretty straightforward,” said Meers.
However, a warning on the insect forecast page makes this point:
“Any producers that grow canola in southern Alberta and into the south portion of central Alberta will have to check their canola crops as they come into flower. The earliest flowering canola crops tend to have the highest risk from cabbage seedpod weevil and should be monitored very closely.”
The weevils are not particularly cold hardy, but they can overwinter in headlands and field trash. Meers said last year’s longer winter likely reduced numbers, but this year has been relatively mild.
“We’re going to deal with it as long as we grow canola in southern Alberta.”
As for grasshoppers, Meers said weather and moisture conditions play a major role in grasshopper numbers. Risk has been increasing in recent years in the south but has decreased in central Alberta and the Peace region.
“If we have the perfect conditions for them in the spring, we will need to spray for grasshoppers in southern Alberta,” said Meers.
Wheat stem sawfly is not expected to be an issue this year for most farmers.
“Unless you’re in Forty Mile, you’re probably not going to be worrying about it.”
Pea leaf weevil is another story. Forecasts indicate this insect could force farmers to spray across a wide portion of the province.
Meers said farmers in Kneehill County, which includes the Three Hills area, should use seed treatments to reduce risk in the northern range of the weevil.
Though the pea leaf weevil range hasn’t expanded much, Meers said its intensity has, possibly because of an increase in fababean acres.
“I really think that this is connected to fababeans,” he said.
That crop is attractive to the insect.
Diamondback moths don’t overwinter in Canada but can enter from the United States. Last year they caused crop damage in the Foremost area, with about 30,000 acres sprayed.
The pest monitoring network has 30 sentinel sites designed to trap incoming moths this spring and gauge the likelihood of threshold levels.
Meers said the 319 soil samples in 60 counties and municipal districts this fall showed interesting wheat midge results.
Based on overwintering cocoons, the Peace region is unlikely to have a problem, but areas around Two Hills, Smoky Lake and Vermilion have potential. The irrigated wheat region around Bow Island is another possible hot spot for wheat midge.
Meers noted the strong connection between high moisture and high midge numbers.
“We’ve seen in Newell County in the past, we’ve seen substantial yield losses for people that don’t pay attention to this,” said Meers.
“Irrigated wheat is just like that high rainfall area. You’re creating (conditions) perfect for midge.”
There is some parasitism in wheat midge, which can help with control.
Bertha armyworm might be a problem in Forty Mile County and west of Edmonton, said Meers.
“If you pushed me, I would say that this area to the west of Edmonton is probably poised for another year of bertha armyworm.”
Meers said an increase in hemp acres could create new insect challenges because many insects like that crop, including bertha and lygus bugs.
A relatively new threat is the European skipper, a small orange butterfly that was seen in relatively high numbers last year in central Alberta.
It feeds on grasses and is especially fond of timothy. It has also been found in winter wheat near Mayerthorpe.
Meers said it is unlikely to be a huge economic problem, but if it does proliferate, timothy will be the first target.
Alberta lists its insect forecasts and maps at bit.ly/1f7nmeT