Methodology

The 2020 grasshopper forecast map is based on adult grasshoppers counts conducted in early August 2019 by Agriculture Fieldmen across the province. In a new initiative launched in 2017, a modified sampling protocol and training was offered, which has reduced the workload for agriculture fieldmen and increased the forecast’s accuracy.

The adult grasshopper counts give an indication of the number of individuals 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 and then make the appropriate decisions if control measures are required.

Survey findings

Peace River Region and Central Alberta

The 2019 grasshopper survey found moderate to high levels of grasshoppers throughout most of the Peace River Region and northern portions of central Alberta and growing grasshopper populations in southern Alberta. Investigations in the Peace and northern portions of central Alberta indicate that the most common species, Melanoplus bruneri was in low numbers in 2018 but higher in 2019. This is a species that wasn’t recognized as a pest until very recently. M. bruneri also has documented populations of biennial lifecycle. This biennial lifecycle has a profound its impact on grasshopper forecasts. To view previous year forecasts see: Historical grasshopper population maps.

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 2019 indicate that 2020 will be a low grasshopper year followed by a higher population in 2021.

Southern Alberta

In southern Alberta, consecutive dry summers is resulting in increasing grasshopper numbers. This is especially true in the M.D. of Acadia, Vulcan, Willow Creek, Lethbridge, Cardston, Magrath and Forty Mile. 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.

Portions of southern Alberta indicating moderate to severe risk could experience problems with grasshoppers if environmental conditions favor grasshopper hatching and development 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 2020 will determine the extent of the grasshopper problems later this growing season. Infestation levels in individual fields are NOT indicated in this forecast map.

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.

Control measures

If insecticides are needed, note label precautions regarding user safety and 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.

Acknowledgements

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.

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.

Resources

Economic thresholds for insects attacking forages

Economic thresholds for insects attacking special crops

Economic thresholds for insects attacking cereals and corn

Contact

Please note: our phone lines are experiencing technical issues due to high traffic. If you are having problems getting through, contact us by email: aginfocentre@gov.ab.ca

Connect with the Ag-Info Centre:

Hours: 8 am to 5 pm (open Monday to Friday, closed statutory holidays)
Toll free: 310-FARM (3276)
Phone: 403-742-7901 (outside Alberta)
Email: aginfocentre@gov.ab.ca