Southeast Alberta could be facing an invasion on three fronts this growing season if the latest insect forecast maps from Alberta Agriculture and Forestry prove accurate. Grasshoppers, pea weevils and cabbage seedpod weevil numbers are all on the rise and have the potential to reach severe levels in some areas in 2017.
Part of this rising tide is to do with weather patterns, says Mark Cutts, a crop specialist with the Alberta Agro-Info Centre, and part of it is to do with natural breeding cycles.
“A long, open fall allows the adults a longer period of time to lay eggs, and then, ultimately, if conditions are right in the spring you can get some significant hatches,” says Cutts. “Insect pests are also typically cyclical. It looks like we’re at the height of that cycle (for some of these) right now.”
Of the three, grasshoppers are of least concern for the Medicine Hat region.
“Grasshoppers thrive in dry years,” says Cutts. “What we saw last year was going into the year we had some areas at higher risk (like Medicine Hat), but the later moisture conditions, I believe, set the numbers back fairly significantly.”
Pea weevils are also not as major a problem coming into 2017, but the trend is rising. A mild or cold winter could tilt that balance one way or the other, says Cutts.
“This past year was a big year for pea leaf weevil because the number of acres of peas were up significantly. So they had lots of what they needed to carry on their lifecycle. The pea leaf weevils over-winter as adults so if they make it through the winter, and the conditions are right for them to start moving around and finding those pea fields, they are going to go find them and start carrying out that process of mating and laying eggs.”
The most severe infestation facing southeast Alberta will come from cabbageseedpod weevils. Studies done in August show the number of adult insects at already severe levels throughout much of southern Alberta. If those critters successfully hatch a new brood, the problem will be significantly worse in 2017.
“That’s one, for sure, producers will have to keep their eyes open for,” warns Cutts. “The big things with cabbage seedpod weevil is they are basically going to really key in on those first canola fields that are flowering. If you have one of the first canola fields in flower in a particular area, you are going to find them.”
Cutts says it may be best to hope for a longer, colder winter stretch ahead.
“Time will tell, but it certainly helps that the winter has been cooler (so far). If the winter went on for a longer period of time, that might be a positive impact as well.”