Alberta insect forecast and survey maps now available
By Alberta Agriculture
Alberta Agriculture releases the 2019 Wheat Midge Forecast Map, Pea Leaf Weevil Survey and the 2019 Wheat Stem Sawfly Forecast Map, allowing producers to make informed decisions on which pest threats to watch and seed treatments to use.
By Alberta Agriculture
Scott Meers, insect management specialist with Alberta Agriculture and Forestry, explains what the pest forecast maps and surveys indicate. Overall Meera indicates that the wheat midge threat has decreased while wheat stem sawfly numbers are on the rise. Pea leaf weevil numbers are also low. The drier-than-average conditions experienced in southern Alberta could be a factor in the shifting patterns in pest prevalence.
Meers says that wheat midge numbers on the whole are down quite substantially. “When we look at the map it shows no patches of yellow, orange or red. It is just a few yellow dots here and there, in amongst lower populations. There will be individual fields still at risk even though the overall forecast is down. There are still little hot spots scattered through central Alberta and into the Peace region.”
The wheat stem sawfly numbers, on the other hand, are the complete opposite. Explains Meers, “We are actually seeing sawfly numbers increasing in a number of areas. The traditional areas such as the MD of Acadia, Special Area No. 3, in Foremost – County of Forty Mile, Vulcan County, the MD of Willow Creek and parts of Lethbridge County – are all showing increases in the wheat stem sawfly numbers. We are actually finding low numbers in areas such as the MD of Foothills and up into Rocky View County as well.”
“It is a definite upward trend in wheat stem sawfly numbers overall, and nowhere near like it was in the early 2000s. If we continue on our dry trend in southern Alberta, we will be watching sawfly increase in severity and importance along with the dry weather.”
Meers says that the pea leaf weevil survey found low overall numbers. “When we look at year over year, in the last five years, this is the lowest level of damage across the board. It does not mean that they have gone away completely.”
“We see an east-west divide where the east is quite low in pea leaf weevil numbers all along the east side of the province. Southern Alberta is still relatively high. Along the Highway 2 corridor and up all the way north of Edmonton, we are seeing substantial pea leaf weevil numbers. However, we are recognizing that overall, the numbers are down from previous years.”
As for seed treatment, he says that it can be a tough call. “Generally if you are in a traditional area, we are still recommending pea leaf weevil control using seed treatment. If you are outside those traditional areas and haven’t experienced large populations in the past, then we are not recommending pea leaf weevil seed treatment management.”
The remaining maps are scheduled to come out mid-January, including those for grasshopper, bertha armyworm and cabbage seed pod weevil.
Read the 2019 Forecast Maps/2018 Survey Maps.