Looking for trouble? You should be when it comes to insects that might be a threat to your crops. The “big three” this year are bertha army worm, grasshoppers, and wheat stem sawfly, says provincial pest specialist Scott Meers.
But it depends where you farm, so Meers recommends you bookmark the website of the Alberta Insect Pest Monitoring Program, first checking out last year’s survey maps and then this year’s forecasts and (later in the growing season), the live insect reports.
“All the forecast maps do is tell you if the risk is high in your area and if so, you need to go check your fields,” said Meers. “There is no direct recommendation to spray — it’s strictly information that your risks are higher and therefore you need to pay more attention.”
That said, a lot of producers are going to be paying attention to this trio:
Public Enemy No. 1: Bertha Army Worm
Populations have been increasing in east-central Alberta between Camrose and Vermilion, and there’s a noticeable buildup in the central Peace.
“We won’t really know until we get into the monitoring season, but every indication says we are going to have an outbreak in 2019,” said Meers.
Bertha army worm is primarily attracted to canola but will feed on pretty much any broadleaf crop.
“They really, really like quinoa and we’ve seen them cause significant damage to fababeans in the past.”
Because it loves Alberta so much, bertha army worm gets a lot of attention — there will be counts of the insect from 350 traps throughout the province, said Meers.
“Those traps will go up mid-June and will run until the end of July. By the third week in July we will have a pretty good indication of what we’re expecting for a bertha army worm outbreak.”
For quick results, just Google ‘bertha army worm monitoring Alberta.’
Public Enemy No. 2: Grasshoppers
There were higher populations in some areas last year — and it looks like a trend is developing.
“There is a forecast for increasing grasshoppers in southwestern Alberta including Vulcan, Lethbridge, Willow Creek, and continuing to Cardston and Warner,” said Meers. “If we get another spring favourable to grasshoppers we could have some serious outbreaks down there.”
Peace Country down through north-central Alberta bears watching as traditionally, grasshoppers in these areas seem to have a schedule.
“They seem to outbreak every other year in odd-numbered years.”
But a dry, warm spring matters more than the calendar.
“If we get heavy rainfall (in May and early June), we often see the freshly hatched grasshoppers are negatively impacted. After that point, their populations are not really weather related. They’re pretty tough.”
Grasshoppers prefer cereals but since they consume as much as 100 milligrams of plant material daily, they’ll eat whatever is in front of them, including canola, lentils, and peas.
Public Enemy No. 3: Wheat Stem Sawfly
These baddies also found southern Alberta to their liking last year.
“We are seeing increases in wheat stem sawfly in 40-Mile County and the Foremost areas, the southern parts of the MD of Taber over into Warner and up into Willow Creek and Vulcan and parts of Lethbridge,” said Meers. “I would also say that we are seeing an increase in the Special Areas in the eastern part of southern Alberta.”
It’s what’s grown in drier regions that attracts the aptly named pest.
“Those drier areas tend to have a heavy wheat component in their rotations.”
Forces for good
A bit of good news is that wheat midge seems to be on the decline.
“Wheat midge is at an all-time low level right now and seems to have run its cycle,” said Meers. “It looks like parasitism has held the populations in check. However, we have some individual fields in central Alberta that are at moderate risk. For producers, if they are getting midge downgrading, they need to pay really close attention to wheat midge in season.”
Areas that regularly have problems with cabbage seed and pea leaf weevils will likely continue to have problems with those pests.
But again, use the provincial data to enhance your scouting. The pest monitoring network also has specifics on scouting periods.
“If you look at the cabbage seed pod weevil, for example, the scouting period is the early flower — if you scout prior to the flower or at the end of flowering, you miss your opportunity to manage that issue,” said Meers.
“That’s why there’s some power in these maps. There are always links from the maps to further information on those species. Dig into some of the life cycle and scouting recommendations that are tied to the maps.”
Lastly, remember Twitter has a constructive side.
“Every Wednesday at 10 a.m. we do tweet chats where we talk about what’s hot and what’s going on that week,” he said.
“We have a Twitter outreach during the summer months — that’s a good way to know what’s happening.”