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| Investigations in those areas have shown that the most common species, Melanoplus bruneri was in low numbers in 2018. This is a species that wasn’t recognized as a pest until very recently. M bruneri also has documented populations of biennial lifecycle.
This is a possible explanation for the outbreaks in alternate years that have resulted in very wrong forecasts for the past 10 plus years (in the Peace River region and northern central Alberta). Investigations are underway assess the possibility of this biennial lifecycle and its impact on grasshopper forecasts. See the past 11 years of grasshopper forecasts here.
Note that a forecast for a particular year is based on the grasshopper count from the previous August. If the grasshopper population in the Peace River Region and northern central Alberta is following a biennial cycle then the grasshopper counts from 2017 indicate that 2019 could be a high grasshopper year |
In southern Alberta consecutive dry summers is resulting in increasing grasshopper numbers. This is especially true in parts of the Special Areas and western southern Alberta (Vulcan, Willow Creek, Lethbridge, Cardston and Magrath) The grasshopper species found in southern Alberta are a blend of Melanoplus bivitattus, M. packardi, M. sanguinipes and Camnula pellucida. The rest of the province shows light to low grasshopper populations.
The western portions of southern Alberta that are indicating moderate to severe risk could experience problems with grasshoppers if environmental conditions favor the hatching and development of grasshoppers in late May through June. Localized factors such as light soils or south facing slopes result in an elevated risk of grasshopper infestations. Conditions in late spring 2019 will determine the extent of the grasshopper problems later this growing season. Infestation levels in individual fields are NOT indicated in this 2019 Grasshopper Forecast Map.
The 2019 grasshopper forecast map is based on adult grasshoppers counts conducted in early August of 2018 by participating Agriculture Fieldmen across the province. In a new initiative launched in 2017 a modified sampling protocol and training was offered. This should both reduce the workload for agriculture fieldmen and increase the accuracy of the forecast. The adult grasshopper counts give an indication of the number of individuals that are capable of reproduction and egg laying. Environmental factors can result in higher or lower actual populations than forecast. Individual producers need to be aware of the potential risks in their area and monitor fields accordingly to be prepared to make the appropriate decisions if control measures are warranted.
Two stripe grasshopper (Melanoplus bivitattus) on canola
Shelley Barkley, Alberta Agriculture and Forestry | 
Clearwing grasshopper (Camnula pellucida)
Hind leg removed so wing markings are noticeable
Shelley Barkley, Alberta Agriculture and Forestry |
On individual farms, particular attention should be paid to areas that traditionally have higher grasshopper populations. In addition, grasshoppers tend to lay their eggs near areas of green growth in the fall that will provide potential food sources for emerging young the following spring. Areas with early green plant growth such as field margins, fence-lines and roadsides are also areas that will give early indications of potential grasshopper problems.
If insecticides are needed, note label precautions regarding user safety, proper application techniques and instructions to reduce impacts on non-target organisms. It is important to remember that control measures are intended to protect the crops from economic damage and are never successful in totally eliminating grasshopper populations.
Follow this link for a printable version of the grasshopper map.
Follow this link for economic threshold information for grasshoppers.
Frequently Asked Questions
Grasshoppers: Lifecycle, Damage Assessment and Management Strategy
Historic Grasshopper Maps from 2008 to 2019.
Alberta Agriculture and Forestry acknowledges the commitment and support of the Agriculture Fieldmen across the province in conducting the surveys essential to the creation of this forecast.
The data management for this survey was done by Jan Lepp of Alberta Agriculture and Forestry.
Thank you David Giffen, Agriculture and Agri-Food Canada, Saskatoon for building the map. |
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