Methodology

The 2022 grasshopper population map is based on adult grasshoppers counts conducted in August 2021 by agricultural fieldmen across the province. 

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.

For information on identification, life cycle, damage and pest management, see Grasshopper – Overview.

Survey findings

Peace River Region and Central Alberta

The 2021 grasshopper survey found light to severe levels of grasshoppers throughout most of the Peace River Region. Investigations in the Peace and northern portions of central Alberta indicate that Melanoplus bruneri was the most common species in 2021. Melanoplus bruneri (Bruner’s spur-throat grasshopper) has been documented as having a biennial lifecycle which has a profound impact on the grasshopper forecasts. The grasshopper forecast map 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 2021 indicate that 2022 will be a low grasshopper year followed by a higher population in 2023 and that 2024 will be a low year. Scouting in the spring is vital to confirm this on individual farms.

Southern Alberta

In southern Alberta, dry summers are resulting in increasing grasshopper numbers. This is especially true in the counties south of, and bordering Highway 1. Populations are increasing in the dryer areas along the Alberta-Saskatchewan border too. The 2021 growing season coupled with a long, warm fall was ideal for grasshopper egg laying.

“Lesser migratory grasshopper, Melanoplus sanguinipes, a pest of cereals and oilseeds, was low in density, and low in relative abundance across much of Alberta, and nearly absent in the area from Lethbridge to the USA and east to Saskatchewan. Lesser migratory grasshopper, like all of the pest species, increase in numbers locally when warm, dry spring and summer weather allow.

Two-striped grasshopper, Melanoplus bivitattus, increased in abundance in 2021 across southern Alberta, with hot spots of over 100 per square meter in areas near Carmangay, Skiff, Foremost, Lethbridge, and east to the Saskatchewan border. Variability also increased, hot spots were separated by large areas of with no Melanoplus bivitattus to be found. The fungal disease, E. grylli, a common sight in some areas, killed thousands in southern Alberta in 2021. Two-striped grasshopper is expected to increase in numbers and range in 2022. Packard’s grasshopper, remains much lower and more restricted to roadsides near grass and hay.

Clear-winged grasshopper increased density in southern Alberta, and in Peace River, but remain much lower in numbers than other dominant species.” Dan Johnson, October 2021.

Portions of southern Alberta indicating moderate to severe risk could experience problems with grasshoppers if environmental conditions favour 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 2022 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. It is easier to scout and control grasshoppers earlier in their lifecycle rather than waiting until they are more mobile.

Acknowledgements

Thank you to the Alberta agricultural fieldmen who complete this survey for us, your help is so valuable to the continuation of this very important work. Thank you to Cypress County for your assistance with data entry. Thank you Dan Johnson for you contribution to this summary. Lastly thank you David Giffen, Agriculture and Agri-Food Canada, Saskatoon for building the map.

Historical population maps

Resources

Economic thresholds for insects attacking forages

Economic thresholds for insects attacking special crops

Economic thresholds for insects attacking cereals and corn

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