Three additional insect forecast and survey maps now available

  From the January 28, 2019 issue of Agri-News
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 Three more insect forecast and survey maps – 2018 Bertha Armyworm Survey, 2019 Grasshopper Forecast and 2018 Cabbage Seedpod Weevil Survey – are now live. Scott Meers, insect management specialist with Alberta Agriculture and Forestry explains what those maps and surveys indicate.

Bertha armyworm

Meers says that bertha armyworm is trending upwards and there could be some outbreaks. “Last year we saw quite a substantial jump up in central Alberta. I fully expect we are going to see an outbreak phase someplace in central Alberta this growing season.”

He adds that it looks like an outbreak that is growing in the Peace Country. “We also have a couple questions further south of Highway 1, but we see that up and down over the years, and often it is not an outbreak. However, it really does look like central Alberta is in for bertha armyworm – it is hard to read exactly where - but probably centered around Camrose.”


As for the 2019 grasshopper forecast, Meers says that a few interesting things are happening. “We are seeing in southwest Alberta – Vulcan, Willow Creek and Lethbridge counties – higher grasshopper numbers in 2018. That forecasts into bigger numbers in 2019, depending on factors such as spring weather. There were problem spots in 2018, and there is potential for those to increase in 2019.”

“The 2019 grasshopper forecast map shows a very low number for the Peace, but we have been seeing a two-year cycle in that region. If we follow that pattern and we look at the map based on the 2017 survey, it looks like we could be in an outbreak situation. We say if because we just don’t have the scientific basis to make that call, but all the trends show a two-year cycle. Given the pattern of every other year, 2019 very likely will be a grasshopper year in the Peace.”

Cabbage seedpod weevil

Meers says that he has seen a retraction in the cabbage seedpod weevil range. “We were finding it almost to Vermilion, the east part of the province, and Edmonton to the west, and we have seen that back off.”

“That is related to winter weather conditions. We had a couple harsh winters, and this year we are having a very nice warm winter. Because of that, we will probably see a higher cabbage seedpod weevil number into 2019.”

“We saw a bit of resurgence - not a lot of high populations - but higher than in 2017. I believe what we are looking at are higher numbers in the traditional areas. They may be creeping back into those non-traditional areas in central Alberta, but certainly not at the threshold numbers. Threshold numbers will likely be seen south of Calgary. I would recommend that we watch all canola – basically Red Deer to Provost and south just in case there is a hot spot in there.”

“It is always important to scout. The maps give us general guidelines and the level of risk, but decisions have to be made on a field-by-field case-by-case situation,” he adds.

A number of maps are updated during the growing season, including diamondback moth, cabbage seedpod weevil, cutworm and bertha armyworm. Explains Meers, “It is really important to follow the bertha armyworm map because it gives us a two-to-three-week head start on where the actually outbreaks will be. There will be about 300 sites across the province this growing season, and that will hopefully point out to us which areas are at highest risk.”

Read the 2019 Forecast Maps/2018 Survey Maps including ones for wheat midge, pea leaf weevil and wheat stem sawfly. For more information, contact


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For more information about the content of this document, contact Scott Meers.
This document is maintained by Christine Chomiak.
This information published to the web on January 25, 2019.