Tag: Melanoplus sanguinipes

Predicted grasshopper development

The grasshopper (Acrididae: Melanoplus sanguinipes) model predicts development using biological parameters known for the pest species and environmental data observed across the Canadian prairies on a daily basis. Model outputs provided below as geospatial maps are a tool to help time in-field scouting on a regional scale yet local development can vary and is only accurately assessed through in-field scouting.

Model simulations were used to estimate grasshopper development as of August 21, 2022. Potential risk continues to be greatest across central and southern regions of Saskatchewan and southeastern Alberta. Simulations indicate that prairie populations are in the adult stage and that females are laying eggs in the soil. Since last week, model simulations indicate that oviposition is now occurring across all of the prairies (Fig. 1). Earlier oviposition can result in above-average production of eggs and increased overwintering survival of eggs.

The oviposition index provides a method to assess where egg production is greatest; higher oviposition index values indicate where egg production is greatest. Model runs for the 2022 growing season (April 1 – August 21) predict that oviposition rates have been greatest across a large region that extends from east of Lethbridge to Regina and north to Saskatoon (Fig. 1).

Figure 1. Grasshopper (*Melanoplus sanguinipes*) oviposition index across the Canadian prairies as of **August 21, 2022** . Higher ovipositional index values indicate greater potential for oviposition.

Grasshopper Scouting Tips:
● Review grasshopper diversity and photos of nymphs, adults, and non-grasshopper species to aid in-field scouting from egg hatch and onwards.
● Access the PPMN’s Grasshopper Monitoring Protocol as a guide to help implement in-field monitoring.
● Review grasshopper lifecycle, damage and scouting and economic thresholds to support sound management decisions enabling the preservation of beneficial arthropods and mitigation of economic losses.

Biological and monitoring information (including tips for scouting and economic thresholds) related to grasshoppers in field crops is posted by Manitoba Agriculture and Resource Development, Saskatchewan Agriculture, Alberta Agriculture and Forestry, the BC Ministry of Agriculture, and the Prairie Pest Monitoring Network. Also, refer to the grasshopper pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (2018) accessible as a free downloadable PDF in either English or French on our new Field Guides page. Review the historical grasshopper maps based on late-summer in-field counts of adults performed across the prairies.

Predicted grasshopper development

Model simulations were used to estimate grasshopper development as of August 14, 2022. Potential risk continues to be greatest across central and southern regions of Saskatchewan and southeastern Alberta. Simulations indicate that prairie populations are in the adult stage and females are beginning to lay eggs in the soil. Earlier oviposition can result in above-average production of eggs and increased overwintering survival of eggs.

The oviposition index provides a method to assess where egg production is greatest; higher oviposition index values indicate where egg production is greatest. Model runs for the 2022 growing season (April 1 – August 14) predicted that ovipositon rates so far in 2022 have been greatest across southern Saskatchewan and southeastern Alberta (Fig. 1).

Figure 1. Grasshopper (*Melanoplus sanguinipes*) oviposition index across the Canadian prairies as of **August 14, 2022** . Higher ovipositional index values indicate greater potential for oviposition.

Predicted grasshopper development

Some areas of the Canadian prairies are presently experiencing high densities of economically important species. Review lifecycle and damage information for this pest to support in-field scouting.

Model simulations were used to estimate grasshopper development as of August 7, 2022. Potential risk continues to be greatest across central and southern regions of Saskatchewan and southeastern Alberta. Adults should now be occurring across central and southern regions of all three prairie provinces. Females are beginning to lay eggs in the soil. Development of grasshopper populations near Moose Jaw, Saskatchewan suggests that local populations are in the adult stage and that oviposition is progressing (Fig. 1). Model output indicates that populations are transitioning to the egg stage (Fig. 2). Potential risk continues to be greatest across the central and southern regions of Saskatchewan.

Figure 1. Predicted development of the migratory grasshopper (*Melanoplus sanguinipes*) population near Moose Jaw, Saskatchewan **as of August 7, 2022**.

Figure 2. Percentage of the migratory grasshopper (Melanoplus sanguinipes) population expected to be in the egg stage across the Canadian prairies **as of August 7, 2022**.

Earlier oviposition can result in above average production of eggs and increased overwintering survival of eggs. The oviposition index provides a method to assess where egg production is greatest; higher oviposition index values indicate where egg production is greatest. Model runs for the 2022 growing season (April 1 to August 7, 2022) predict that oviposition rates should be greatest near Winnipeg, Manitoba, Moose Jaw, Saskatchewan and Medicine Hat, Alberta (Fig. 3).

Figure 3. Grasshopper (*Melanoplus sanguinipes*) oviposition index across the Canadian prairies as of **August 7, 2022** . Higher ovipositional index values indicate greater potential for oviposition.

Predicted grasshopper development

Some areas of the Canadian prairies are presently experiencing high densities of economically important species. Review lifecycle and damage information for this pest to support in-field scouting.

Model simulations were used to estimate grasshopper development as of July 31, 2022. Grasshopper development has progressed rapidly over the past few weeks and development rates are more advanced this year than expected based on long-term climate normal values. Based on estimates of average development, populations should consist of 4th (18%) and 5th (37%) instar nymphs and adults (33%) across the southern regions of all three prairie provinces (Fig. 1). Adults should now be occurring across the southern regions of all three prairie provinces (Fig. 1). Model output indicates that oviposition (egg-laying) is now occurring across the southern prairies (Fig. 2). Potential risk continues to be greatest across the central and southern regions of Saskatchewan.

Figure 1. Predicted migratory grasshopper (*Melanoplus sanguinipes*) development, presented as **average instar**, across the Canadian prairies **as of July 31, 2022**.

Figure 2. Percent of the migratory grasshopper (Melanoplus sanguinipes) predicted to be in the egg stage across the Canadian prairies **as of July 31, 2022**.

Predicted grasshopper development

Some areas of the Canadian prairies are presently experiencing high densities of economically important species. Review lifecycle and damage information for this pest to support in-field scouting.

Model simulations were used to estimate grasshopper development as of July 24, 2022. As a result of above-normal temperatures, grasshopper development has rapidly progressed over the past few weeks. Last week, adults were just beginning to appear. Based on estimates of average development, populations should consist of 4th (25%) and 5th (34%) instar nymphs and adults (19%) across the southern regions of all three prairie provinces (Fig. 1). Adults should now be occurring across the southern regions of all three prairie provinces (Fig. 2). Potential risk continues to be greatest across the central and southern regions of Saskatchewan.

Figure 2. Long-term average predicted migratory grasshopper (Melanoplus sanguinipes) development, presented as the percent adults, across the Canadian prairies **as of July 17, 2022**.

Predicted grasshopper development

The grasshopper (Acrididae: Melanoplus sanguinipes) model predicts development using biological parameters known for the pest species and environmental data observed across the Canadian prairies on a daily basis. Model outputs provided below as geospatial maps are a tool to help time in-field scouting on a regional scale but local development can vary and is only accurately assessed through in-field scouting.

SCOUT NOW – Some areas of the Canadian prairies are presently experiencing high densities of economically important species. Review lifecycle and damage information for this pest to support in-field scouting.

Model simulations were used to estimate grasshopper development as of July 17, 2022. Based on estimates of average nymphal development, populations should consist of primarily in the 4th and 5th instar and adults across southern regions of all three prairie provinces (Fig. 1). Adults should now be occurring across southern regions of all three prairie provinces (Fig. 2).

Predicted grasshopper development

The grasshopper (Acrididae: Melanoplus sanguinipes) model predicts development using biological parameters known for the pest species and environmental data observed across the Canadian prairies on a daily basis. Model outputs provided below as geospatial maps are a tool to help time in-field scouting on a regional scale but local development can vary and is only accurately assessed through in-field scouting.

SCOUT NOW – Some areas of the Canadian prairies are presently experiencing high densities of nymphs and economically important species are present. Review lifecycle and damage information for this pest to support in-field scouting.

Warm, dry conditions across southern and central regions of the prairies have advanced grasshopper development. Model simulations were used to estimate grasshopper development as of July 10, 2022. Based on estimates of average nymphal development, populations are predicted to consist of primarily 4th and 5th instar stages across all three prairie provinces (Fig. 1). Across most of the prairies, grasshopper development is predicted to be similar to average values; development is delayed across southern Manitoba (Fig. 2).

Figure 2. Long-term average predicted migratory grasshopper (Melanoplus sanguinipes) development, presented as the average instar, across the Canadian prairies as of July 10, based on climate normal data.

Predicted grasshopper development

The grasshopper (Acrididae: Melanoplus sanguinipes) model predicts development using biological parameters known for the pest species and environmental data observed across the Canadian prairies on a daily basis. Model outputs provided below as geospatial maps are a tool to help time in-field scouting on a regional scale but local development can vary and is only accurately assessed through in-field scouting.

Compared with the previous week, warm, dry conditions have advanced grasshopper development, particularly across central and southern regions of the prairies. Model simulations were used to estimate grasshopper development as of July 3, 2022. Based on estimates of average nymphal development, first to fifth instar nymphs should be occurring across southern and central regions of all three prairie provinces (Fig. 1). Across most of the prairies, grasshopper development is predicted to be similar to average values; development is delayed across southern Manitoba (Fig. 2).

Predicted grasshopper development

The grasshopper (Acrididae: Melanoplus sanguinipes) model predicts development using biological parameters known for the pest species and environmental data observed across the Canadian prairies on a daily basis. Model outputs provided below as geospatial maps are a tool to help time in-field scouting on a regional scale but local development can vary and is only accurately assessed through in-field scouting.

Warm, dry conditions across central and southern regions of Saskatchewan have resulted in rapid grasshopper development. Model simulations were used to estimate grasshopper development as of June 26, 2022. The grasshopper hatch is nearly complete for the southern prairies (Fig. 1). Hatch is still progressing across the Parkland and Peace River regions. Based on estimates of average nymphal development, first to fifth instar nymphs should be occurring across southern and central regions of all three prairie provinces (Fig. 2).

Figure 1. Predicted migratory grasshopper (Melanoplus sanguinipes) hatch (%) across the Canadian prairies as of June 26, 2022.

Figure 2. Predicted migratory grasshopper (*Melanoplus sanguinipes*) development, presented as average instar, across the Canadian prairies **as of June 26, 2022**.

Predicted grasshopper development

The grasshopper (Acrididae: Melanoplus sanguinipes) model predicts development using biological parameters known for the pest species and environmental data observed across the Canadian prairies on a daily basis. Model outputs provided below as geospatial maps are a tool to help time in-field scouting on a regional scale but local development can vary and is only accurately assessed through in-field scouting.

Review lifecycle and damage information for this pest to support in-field scouting.

Model simulations were used to estimate percent grasshopper egg development and hatch as of June 19, 2022. Warmer temperatures across the southern prairies have resulted in increased rates of grasshopper egg development and hatch is now well underway. Egg hatch may be nearly complete for some regions.

Last week, the average embryological development was 83 %. This week, average egg development is predicted to be 90 % and is 2 % greater than the long-term development rate for this time in the growing season. Hatch is progressing across the prairies, with southern and central regions of Alberta and Saskatchewan having hatch rates greater than 75% (Fig. 1). Compared to last week, recent warm conditions across southern Manitoba have resulted in higher hatch rates.

Figure 1. Predicted migratory grasshopper (Melanoplus sanguinipes) hatch (%) across the Canadian prairies as of June 19, 2022.

Based on estimates of average nymphal development, first to third instar nymphs should be occurring across southern and central regions of Alberta and Saskatchewan (Fig. 2). Warm, dry conditions across central and southern regions of Saskatchewan have resulted in rapid grasshopper development.

Predicted grasshopper development

The grasshopper (Acrididae: Melanoplus sanguinipes) model predicts development using biological parameters known for the pest species and environmental data observed across the Canadian prairies on a daily basis. Review lifecycle and damage information for this pest. Review the historical grasshopper maps based on late-summer adult in-field counts performed across the prairies.

Model simulations were used to estimate percent grasshopper egg development and hatch as of June 12, 2022. Warmer temperatures over the past 30 days have resulted in increased rates of grasshopper development across Saskatchewan and Alberta; wetter/cooler conditions across eastern Saskatchewan and Manitoba have resulted in delayed development.

Last week, average embryological development was 76 %. This week, average egg development is predicted to be 83 % and is 1 % greater than the long-term development rate. Hatch is progressing across southern and central regions of Alberta and Saskatchewan with hatch rates that range between 15 and 60% (Fig. 1). First to third instar nymphs should be occurring across southern and central regions of Alberta and Saskatchewan. Simulations indicate that 5-10% of the population has hatched across southern and central regions of Manitoba.

Figure 1. Predicted grasshopper (Melanoplus sanguinipes) embryological development (%) across the Canadian prairies as of June 12, 2022.

Risk estimates, based on meteorological inputs, were used to assess the impact of weather on grasshopper development and population growth potential (Fig. 2). Grasshopper risk is greatest in areas that are warmer and drier than normal. As of June 12, 2022, model output indicates that potential risk is greatest across a region that extends from Lethbridge to Swift Current and Saskatoon. Relative to last week, risk has increased for localized areas across the Peace River region. The simulation indicates that even though temperatures are suitable for grasshopper development, excessive moisture across most of Manitoba has reduced the potential risk from grasshoppers. Overall risk is predicted to be similar to long-term average risk and is currently well below potential risk predictions that were produced for the 2021 growing season.

Figure 2. Predicted risk for the migratory grasshopper (*Melanoplus sanguinipes*) across the Canadian prairies **as of June 12, 2022**.

Predicted grasshopper development

Model simulations were used to estimate percent grasshopper egg development and hatch as of June 5, 2022. Recent warmer temperatures in Saskatchewan and Alberta have resulted in increased rates of grasshopper development. In contrast, cooler/wetter conditions across eastern Saskatchewan and Manitoba have resulted in delayed development. Last week, average embryological development was 73%.

This week, average egg development is predicted to be 76% and is similar to the long-term development rate (Fig. 1). Hatch is progressing across southern and central regions of Alberta and Saskatchewan (Fig. 2). This week grasshoppers (1-3rd instars) were abundant at specific locations across west-central Saskatchewan. Some fields were showing signs of grasshopper feeding.

Figure 1. Predicted grasshopper (Melanoplus sanguinipes) embryological development (%) across the Canadian prairies as of June 5, 2022.

Figure 2. Predicted grasshopper (*Melanoplus sanguinipes*) hatch (%) across the Canadian prairies **as of June 5, 2022**.

Risk estimates, based on meteorological inputs, were used to assess the impact of weather on potential grasshopper development and population growth potential (Fig. 3). A bioclimate simulation model was developed to assess how climatic factors influence occurrence and relative abundance. Potential risk is based on weekly growth index values. Grasshopper risk is greatest in areas that are warmer and drier than normal. As of June 5, 2022, model output indicates that potential risk is greatest across eastern Alberta and western Saskatchewan. Cooler/wetter conditions in eastern Saskatchewan and Manitoba are predicted to reduce potential risk.

Hatch is progressing across southern Alberta and western Saskatchewan (Fig. 3). Last week, grasshopper hatchlings were collected in an area between Saskatoon and Kindersley. Southern Alberta and western Saskatchewan have received the least amount of rain during the growing season. Grasshopper risk can be greater when conditions are warm and dry.

Figure 3. Predicted risk for the migratory grasshopper (*Melanoplus sanguinipes*) across the Canadian prairies as of June 5, 2022.

Predicted grasshopper development

Model simulations were used to estimate percent grasshopper embryonic (egg) development as of May 29, 2022. Recent warmer temperatures have resulted in increased rates of egg development. Last week average development was 64 %. This week, average egg development is predicted to be 73 % with a range of 63-82 % (Fig. 1). In comparison, egg development based on long-term climate data is typically 70 % by this week of the growing season (Fig. 2). Cool conditions in Manitoba and the Peace River region continue to result in slower than average development rates in those areas. Across southern Alberta, the simulation indicates that egg development is similar to long-term average values.

Figure 1. Predicted grasshopper (Melanoplus sanguinipes) embryological development (%) across the Canadian prairies as of May 29, 2022.

Figure 2. Long-term average predicted grasshopper (*Melanoplus sanguinipes*) embryological development (%) across the Canadian prairies **as of May 29 based on climate normals data**.

Figure 3. Predicted grasshopper (*Melanoplus sanguinipes*) grasshopper hatch (%) across the Canadian prairies as of May 29, 2022.

Predicted grasshopper development

Model simulations were used to estimate percent grasshopper embryonic (egg) development as of May 22, 2022. Egg development ranges between 55 and 75% across most of the prairies (average=64%) (Fig. 1). Based on climate normals data, long term average development should be 64% (Fig. 2). Cool conditions in Manitoba and the Peace River region continue to result in slower than average development rates. Across southern Alberta, the simulation indicates that egg development is similar to average values. This region has had the least amount of rain during the growing season.

Grasshopper risk can be greater when conditions are warm and dry. Initial hatch is predicted to have begun near Medicine Hat and Brooks Alberta.

Figure 1. Predicted grasshopper (Melanoplus sanguinipes) embryological development across the Canadian prairies as of May 22, 2022.

Predicted grasshopper development

As of May 8, 2022, the model simulation indicates that egg development is most advanced in southern Alberta (Fig. 1). Cool conditions in Manitoba have resulted in slower development rates. Egg development is expected to range from 50 and 65 % across most of the prairies (average = 59 %). Based on climate normals data, long-term average development should be 57 % (Fig. 2).

Figure 1. Predicted grasshopper (Melanoplus sanguinipes) embryological development across the Canadian prairies as of May 8, 2022.

Figure 2. Predicted grasshopper (*Melanoplus sanguinipes*) embryological development across the Canadian prairies as of May 8 based on long-term average (climate normals) data.

Predicted grasshopper development

Model simulations were used to estimate grasshopper (Melanoplus sanguinipes) development and oviposition as of August 15, 2021. Above-average temperatures during June, July, and early August continue to result in a noticeable increase in the rates of oviposition.

Grasshoppers generally begin to lay eggs in early August. Model simulations for 2021 predicted that oviposition was expected to begin in mid-July. Earlier oviposition can result in above-average production of eggs and increased overwintering survival of eggs. This may result in potential increased grasshopper risk for the 2022 growing season. Model runs for the 2021 growing season (April 1 – August 15) indicated that oviposition should now be occurring across most of the prairies and is predicted to be greatest in southeastern Alberta (Fig. 1).

Figure 1. Grasshopper (*Melanoplus sanguinipes*) oviposition index across the Canadian prairies as of August 8, 2021. ***Higher values indicate greater potential for oviposition.***

Grasshopper Scouting Steps:
● Review grasshopper diversity and scouting information including photos of nymphs, adults, and non-grasshopper species to aid in-field scouting and accurately apply thresholds for grasshoppers.
● Measure off a distance of 50 m on the level road surface and mark both starting and finishing points using markers or specific posts on the field margin.
● Start at one end in either the field or the roadside and walk toward the other end of the 50 m, making some disturbance with your feet to encourage any grasshoppers to jump.
● Grasshoppers that jump/fly through the field of view within a one-meter width in front of the observer are counted.
● A meter stick can be carried as a visual tool to give perspective for a one-meter width. However, after a few stops, one can often visualize the necessary width and a meter stick may not be required. Also, a hand-held counter can be useful in counting while the observer counts off the required distance.
● At the endpoint, the total number of grasshoppers is divided by 50 to give an average per meter. For 100 m, repeat this procedure.
● Compare counts to the following damage levels associated with pest species of grasshoppers:
0-2 per m² – None to very light damage
2-4 per m² – Very light damage
4-8 per m² – Light damage
8-12 per m² – Action threshold in cereals and canola
12-24 per m² – Severe damage
24 per m² – Very severe damage
For lentils at flowering and pod stages, >2 per m² will cause yield loss.
For flax at boll stages, >2 per m² will cause yield loss.
● More practically, the following thresholds are offered but, in the event of additional crop stress (e.g., drought), the use of “may be required” versus “control usually required” requires careful consideration:

Biological and monitoring information (including tips for scouting and economic thresholds) related to grasshoppers in field crops is posted by Manitoba Agriculture and Resource Development, Saskatchewan Agriculture, Alberta Agriculture and Forestry, the BC Ministry of Agriculture, and the Prairie Pest Monitoring Network. Also, refer to the grasshopper pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (accessible in either English-enhanced or French-enhanced versions).

Predicted grasshopper development

Model simulations were used to estimate grasshopper (Melanoplus sanguinipes) development as of August 8, 2021. Compared to average growing season temperatures, above-average temperatures during June, July, and early August continue to result in a noticeable increase in the rate of grasshopper development.

Oviposition generally begins in early August. Model simulations for 2021 predicted that oviposition was expected to begin in mid-July. Earlier oviposition can result in above-average production of eggs resulting in potential risk for the following growing season. Climate data suggests that, as of August 8, oviposition would be expected to occur across most of the southern prairies (Fig. 1). Model runs for the 2021 growing season (April 1 – August 8) predicted that oviposition should now be occurring across most of the prairies (Fig. 2).

Figure 1. Percent of grasshopper (*Melanoplus sanguinipes*) population in the egg stage across the Canadian prairies **as of August 8 (based on climate normals data)**.

Figure 2. Percent of grasshopper (*Melanoplus sanguinipes*) population in the egg stage across the Canadian prairies **as of August 8, 2021**.

Biological and monitoring information (including tips for scouting and economic thresholds) related to grasshoppers in field crops is posted by Manitoba Agriculture and Resource Development, Saskatchewan Agriculture, Alberta Agriculture and Forestry, the BC Ministry of Agriculture, and the Prairie Pest Monitoring Network. Also, refer to the grasshopper pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (accessible in either English-enhanced or French-enhanced versions).

Predicted grasshopper development

Model simulations were used to estimate grasshopper (Melanoplus sanguinipes) development as of August 1, 2021. Compared to average growing season temperatures, above-average temperatures during June and July continue to result in a noticeable increase in the rate of grasshopper development. Based on climate-normals, grasshopper populations near Saskatoon should have been in the fifth instar and adult stages on July 31 (Fig. 1).

Figure 1. Predicted development of Melanoplus sanguinipes populations near Saskatoon, Saskatchewan, **as of August 1, 2021, based on climate normals data)**.

Oviposition generally begins in early August. This year, the average July temperature at Saskatoon was 2.8 °C warmer than normal, resulting in advanced development of grasshopper populations. Based on a survey conducted across central, southern, and western regions of Saskatchewan, adults were observed during the first week of July. Model simulations for 2021 predicted that oviposition was expected to begin in mid-July (Fig. 2).

Figure 2. Predicted development of *Melanoplus sanguinipes* populations near Saskatoon, Saskatchewan, **as of August 1, 2021**.

The onset of oviposition earlier in a growing season can result in above-average production of eggs leading to higher risk of grasshopper issues the following growing season (e.g., 2022). Climate data suggests that, as of August 1, oviposition would be expected to occur in localized areas across the prairies (Fig. 3). Model runs for the 2021 growing season (April 1 – August 1) predicted, as a result of above-normal temperatures, that oviposition should now be occurring across most of the prairies (Fig. 4)

Figure 3. Percent of grasshopper (*Melanoplus sanguinipes*) population in the egg stage across the Canadian prairies as of August 1, 2021 (based on climate normals data).

Figure 4. Percent of grasshopper (*Melanoplus sanguinipes*) population in the egg stage across the Canadian prairies **as of August 1, 2021**.

Biological and monitoring information (including tips for scouting and economic thresholds) related to grasshoppers in field crops is posted by Manitoba Agriculture and Resource Development, Saskatchewan Agriculture, Alberta Agriculture and Forestry, the BC Ministry of Agriculture, and the Prairie Pest Monitoring Network. Also, refer to the grasshopper pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (accessible in either English-enhanced or French-enhanced versions).

Predicted grasshopper development

Model simulations were used to estimate grasshopper (Melanoplus sanguinipes) development as of July 11, 2021. Above-average temperatures in late June and early July have resulted in a noticeable increase in grasshopper development. Grasshopper development should be greatest across southern Manitoba where the majority of the population will be in the adult stage (Fig. 1). Adults should be present across all three provinces; more than 13.5 % of the population should be adults.

Figure 1. Predicted grasshopper (*Melanoplus sanguinipes*) development across the Canadian prairies **as of July 11, 2021**.

Figure 2. Percent of grasshopper (*Melanoplus sanguinipes*) population in the adult stage across the Canadian prairies **as of July 11, 2021**.

The long-term average value for this week of the growing season is less than 1% of the population in the adult stage. Development, as of July 11, 2021, is well ahead of long-term average values (Fig. 3).

Figure 3. Long-term average predicted grasshopper (*Melanoplus sanguinipes*) development, presented as the average instar, across the Canadian prairies **as of July 11, based on climate normals data**.

Biological and monitoring information (including tips for scouting and economic thresholds) related to grasshoppers in field crops is posted by Manitoba Agriculture and Resource Development, Saskatchewan Agriculture, Alberta Agriculture and Forestry, the BC Ministry of Agriculture, and the Prairie Pest Monitoring Network. Also, refer to the grasshopper pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (accessible in either English-enhanced or French-enhanced versions).

Predicted grasshopper development

Model simulations were used to estimate grasshopper (Melanoplus sanguinipes) development as of July 4, 2021. Recent warm conditions have resulted in a noticeable increase in grasshopper development since last week. Grasshopper development, based on average instar, should be greatest across southern Manitoba and southeastern Saskatchewan (Fig. 1).

Figure 1. Predicted grasshopper (*Melanoplus sanguinipes*) development, presented as the average instar, across the Canadian prairies **as of July 4, 2021**.

Across the prairies, more than 15 % of the population should be in the fifth instar (Fig. 2). Development, as of July 4, 2021, is well ahead of long-term average values (Fig. 3).

Figure 2. Percent of grasshopper (*Melanoplus sanguinipes*) population in the 5th instar across the Canadian prairies as of July 4, 2021.

Grasshopper Scouting Steps:
● Review grasshopper diversity and scouting information including photos of both nymphs, adults and non-grasshopper species to aid in-field scouting and accurately apply thresholds for grasshoppers.
● Measure off a distance of 50 m on the level road surface and mark both starting and finishing points using markers or specific posts on the field margin.
● Start at one end in either the field or the roadside and walk toward the other end of the 50 m, making some disturbance with your feet to encourage any grasshoppers to jump.
● Grasshoppers that jump/fly through the field of view within a one-meter width in front of the observer are counted.
● A meter stick can be carried as a visual tool to give perspective for a one-meter width. However, after a few stops, one can often visualize the necessary width and a meter stick may not be required. Also, a hand-held counter can be useful in counting while the observer counts off the required distance.
● At the endpoint, the total number of grasshoppers is divided by 50 to give an average per meter. For 100 m, repeat this procedure.
● Compare counts to the following damage levels associated with pest species of grasshoppers:
0-2 per m² – None to very light damage
2-4 per m² – Very light damage
4-8 per m² – Light damage
8-12 per m² – Action threshold in cereals and canola
12-24 per m² – Severe damage
24 per m² – Very severe damage
For lentils at flowering and pod stages, >2 per m² will cause yield loss.
For flax at boll stages, >2 per m² will cause yield loss.
● More practically, the following thresholds are offered but, in the event of additional crop stress (e.g., drought), the use of “may be required” versus “control usually required” requires careful consideration:

Biological and monitoring information (including tips for scouting and economic thresholds) related to grasshoppers in field crops is posted by Manitoba Agriculture and Resource Development, Saskatchewan Agriculture, Alberta Agriculture and Forestry, the BC Ministry of Agriculture, and the Prairie Pest Monitoring Network. Also, refer to the grasshopper pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (accessible in either English-enhanced or French-enhanced versions).

Predicted grasshopper development

Model simulations were used to estimate grasshopper (Melanoplus sanguinipes) development as of June 27, 2021. The development of grasshopper nymphs, based on average instar, should be most advanced across southern Manitoba and southeastern Saskatchewan (Figure 1). Grasshopper populations south of Winnipeg are predicted to be mostly in the 4th and 5th instar stages. Across the prairies, nymph development, as of June 27, 2021 is well ahead of long term average values (Figure 2).

Figure 1. Predicted grasshopper (*Melanoplus sanguinipes*) development, presented as the average instar, across the Canadian prairies **as of June 27, 2021.**

Figure 2. Long term average predicted grasshopper (*Melanoplus sanguinipes*) development, presented as the average instar, across the Canadian prairies as of June 27, based on climate normals data.

The model was projected to July 13 to determine potential development at Saskatoon and Grande Prairie over the next two weeks. Results suggest that by July 13, Saskatoon populations will primarily be in the fourth and fifth instars with first appearance of adults (Figure 3). Development near Grande Prairie is predicted to be slower, with populations being mostly in the third and fourth instars (Figure 4). Producers are advised to monitor roadsides and field margins to assess the development and densities of local grasshopper populations.

Figure 3. Predicted development, presented as the average instar, of *Melanoplus sanguinipes* populations near Saskatoon, Saskatchewan **as of June 27, 2021 (projected to July 13, 2021)**.

Figure 4. Predicted development, presented as the average instar, of *Melanoplus sanguinipes* populations near Grande Prairie, Alberta as of June 27, 2021 (projected to July 13, 2021).

Biological and monitoring information (including tips for scouting and economic thresholds) related to grasshoppers in field crops is posted by Manitoba Agriculture and Resource Development, Saskatchewan Agriculture, Alberta Agriculture and Forestry, the BC Ministry of Agriculture, and the Prairie Pest Monitoring Network. Also, refer to the grasshopper pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (accessible in either English-enhanced or French-enhanced versions).

Predicted grasshopper development

Model simulations were used to estimate grasshopper (Melanoplus sanguinipes) development as of June 20, 2021. As of June 20, hatch is predicted to be underway across most of the prairies with a prairie average of 69 % (versus 45 % last week). Percent hatch was greater than 90 % across most of Manitoba, Saskatchewan, and southern Alberta. Development in the central and Peace River regions of Alberta has been significantly slower than the rest of the prairies (Fig. 1).

Figure 1. Predicted grasshopper (*Melanoplus sanguinipes*) hatch (%) across the Canadian prairies **as of June 20, 2021**.

Development of grasshopper nymphs, based on average instar, should be greatest across southern Manitoba and southern Saskatchewan (Fig. 2). Grasshopper populations south of Winnipeg are predicted to be mostly in the 3rd and 4th instar stages. Across the prairies, nymph development, as of June 20, 2021, is well ahead of long-term average values across most of the prairies (Fig. 3).

Figure 2 Predicted grasshopper (*Melanoplus sanguinipes*) development, presented as the average instar, across the Canadian prairies as of June 20, 2021.

The model was projected to July 6 to determine potential development at Winnipeg and Lethbridge over the next two weeks. Results suggest that by July 6, Winnipeg populations will primarily be in the fourth and fifth instars with the first appearance of adults (Fig. 4). Development near Lethbridge is predicted to be slower, with populations being mostly in the third and fourth instars (Fig. 5). Producers are advised to monitor roadsides and field margins to assess the development and densities of local grasshopper populations.

Figure 4. Predicted development, presented as the average instar, of *Melanoplus sanguinipes* populations near Winnipeg, Manitoba as of June 20, 2021 (projected to July 6, 2021).

Figure 5. Predicted development, presented as the average instar, of *Melanoplus sanguinipes* populations near Lethbridge, Alberta **as of June 20, 2021 (projected to July 6, 2021)**.

Grasshopper Scouting Steps:
● Review grasshopper diversity and scouting information including photos of both nymphs, adults and non-grasshopper species to aid in-field scouting and accurately apply thresholds for grasshoppers.
● Measure off a distance of 50 m on the level road surface and mark both starting and finishing points using markers or specific posts on the field margin.
● Start at one end in either the field or the roadside and walk toward the other end of the 50 m, making some disturbance with your feet to encourage any grasshoppers to jump.
● Grasshoppers that jump/fly through the field of view within a one-meter width in front of the observer are counted.
● A meter stick can be carried as a visual tool to give perspective for a one-meter width. However, after a few stops, one can often visualize the necessary width and a meter stick may not be required. Also, a hand-held counter can be useful in counting while the observer counts off the required distance.
● At the endpoint, the total number of grasshoppers is divided by 50 to give an average per meter. For 100 m, repeat this procedure.
● Compare counts to the following damage levels associated with pest species of grasshoppers:
0-2 per m² – None to very light damage
2-4 per m² – Very light damage
4-8 per m² – Light damage
8-12 per m² – Action threshold in cereals and canola
12-24 per m² – Severe damage
24 per m² – Very severe damage
For lentils at flowering and pod stages, >2 per m² will cause yield loss.
For flax at boll stages, >2 per m² will cause yield loss.
● More practically, the following thresholds are offered but, in the event of additional crop stress (e.g., drought), the use of “may be required” versus “control usually required” requires careful consideration:

Biological and monitoring information (including tips for scouting and economic thresholds) related to grasshoppers in field crops is posted by Manitoba Agriculture and Resource Development, Saskatchewan Agriculture, Alberta Agriculture and Forestry, the BC Ministry of Agriculture, and the Prairie Pest Monitoring Network. Also, refer to the grasshopper pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (accessible in either English-enhanced or French-enhanced versions).

Predicted grasshopper development

Model simulations were used to estimate grasshopper (Melanoplus sanguinipes) development as of June 13, 2021. Average development of eggs is 90 % and well ahead of the long-term average of 80 %. As of June 13, the hatch is predicted to be underway across most of the prairies with a prairie average of 45 % (versus 26 % last week). Hatch rates were greater than 75 % across southern Manitoba, Saskatchewan and Alberta. Development in central and Peace River regions of Alberta has been significantly slower than the rest of the prairies (Fig. 1).

Figure 1. Predicted grasshopper (*Melanoplus sanguinipes*) hatch (%) across the Canadian prairies **as of June 13, 2021**.

Development of grasshopper nymphs, based on average instar, is greatest across Manitoba (Fig. 2). Above normal temperatures have resulted in the rapid development of grasshopper populations across Manitoba and Saskatchewan. Grasshopper populations south of Winnipeg are predicted to be mostly in the 3rd and 4th instar stages. Nymph development, as of June 13, 2021, is greater than long-term average values across most of the prairies (Fig. 3).

Figure 2 Predicted grasshopper (*Melanoplus sanguinipes*) development, presented as the average instar, across the Canadian prairies as of June 13, 2021.

Fig. 3. Long-term average predicted grasshopper (*Melanoplus sanguinipes*) development, presented as the average instar, across the Canadian prairies as of June 15 based on climate normals data.

The model was projected to June 29 to determine potential development at Saskatoon and Winnipeg over the next two weeks. Results suggest that by June 29, Saskatoon populations will primarily be in the third and fourth instar with first appearance of fifth instar nymphs (Fig. 4) whereas near Winnipeg development is predicted to be faster, with populations being mostly in the fourth and fifth instars (Fig. 5). Producers are advised to monitor roadsides and field margins to assess the development and densities of local grasshopper populations.

Figure 4. Predicted development, presented as the average instar, of *Melanoplus san**guinipes* populations near Saskatoon, Saskatchewan as of June 13, 2021 (projected to June 29, 2021).

Figure 5. Predicted development, presented as the average instar, of *Melanoplus sanguinipes* populations near Winnipeg, Manitoba as of June 13, 2021 (projected to June 29, 2021).

Grasshopper Scouting Steps:
● Measure off a distance of 50 m on the level road surface and mark both starting and finishing points using markers or specific posts on the field margin.
● Start at one end in either the field or the roadside and walk toward the other end of the 50 m, making some disturbance with your feet to encourage any grasshoppers to jump.
● Grasshoppers that jump/fly through the field of view within a one-meter width in front of the observer are counted.
● A meter stick can be carried as a visual tool to give perspective for a one-meter width. However, after a few stops, one can often visualize the necessary width and a meter stick may not be required. Also, a hand-held counter can be useful in counting while the observer counts off the required distance.
● At the endpoint, the total number of grasshoppers is divided by 50 to give an average per meter. For 100 m, repeat this procedure.
● Compare counts to the following damage levels associated with pest species of grasshoppers:
0-2 per m² – None to very light damage
2-4 per m² – Very light damage
4-8 per m² – Light damage
8-12 per m² – Action threshold in cereals and canola
12-24 per m² – Severe damage
24 per m² – Very severe damage
For lentils at flowering and pod stages, >2 per m² will cause yield loss.
For flax at boll stages, >2 per m² will cause yield loss.

Biological and monitoring information (including tips for scouting and economic thresholds) related to grasshoppers in field crops is posted by Manitoba Agriculture and Resource Development, Saskatchewan Agriculture, Alberta Agriculture and Forestry, the BC Ministry of Agriculture, and the Prairie Pest Monitoring Network. Also, refer to the grasshopper pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (accessible in either English-enhanced or French-enhanced versions).

Predicted grasshopper development

Model simulations were used to estimate grasshopper (Melanoplus sanguinipes) development as of June 6, 2021. Average development of eggs is 86 % and is well ahead of the long term average of 73 %. Last week’s warm conditions across southeastern SK and southern Manitoba have been responsible for advanced development of eggs near Regina, Saskatoon, Brandon, and Winnipeg. Egg development is predicted to exceed 90 % across most of the southern prairies (Fig. 1).

Figure 1. Predicted grasshopper (*Melanoplus sanguinipes*) embryological development (%) across the Canadian prairies as of June 6, 2021.

As of June 6, hatch was predicted to be occurring across most of the prairies (overall average was 26 %) with hatch rates approaching 30-45 % across southern Manitoba and Saskatchewan (Fig. 2). The model was projected to June 22 to determine potential development at Regina and Swift Current over the next two weeks (Figs. 3 and 4). Results suggest that by June 22, Regina populations will primarily be in the third instar, with first appearance of fourth instars. Development near Swift Current is predicted to be slower, with populations being mostly in the first and second instars.

Warm, dry conditions continue to persist across Manitoba. This may result in conditions conducive to crop damage from grasshoppers as hatch progresses in June. Producers are advised to monitor roadsides and field margins to assess development and densities of local grasshopper populations.

Figure 2. Predicted grasshopper (*Melanoplus sanguinipes*) hatch (%) across the Canadian prairies as of June 6, 2021.

Figure 3. Predicted development of *Melanoplus sanguinipes* populations near Regina, Saskatchewan **as of June 6, 2021 (projected to June 22, 2021)**.

Figure 4. Predicted development of *Melanoplus sanguinipes* populations near Swift Current, Saskatchewan as of June 6, 2021 (projected to June 22, 2021).

Biological and monitoring information related to grasshoppers in field crops is posted by Manitoba Agriculture and Resource Development, Saskatchewan Agriculture, Alberta Agriculture and Forestry, the BC Ministry of Agriculture and the Prairie Pest Monitoring Network. Also refer to the grasshopper pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (accessible in either English-enhanced or French-enhanced versions).

Predicted grasshopper development

The grasshopper simulation model will be used to monitor grasshopper development across the prairies. Weekly temperature data collected across the prairies is incorporated into the simulation model which calculates estimates of grasshopper development stages based on biological parameters for Melanoplus sanguinipes (Migratory grasshopper).

Model simulations were used to estimate grasshopper egg development as of May 30, 2021. Average development of eggs is 78 % and is well ahead of the long-term average of 67 %. Warm conditions across southeastern Saskatchewan and southern Manitoba (May 1-30) have been responsible for the advanced development of eggs near Regina, Saskatoon, Brandon and Winnipeg (Fig. 1). Egg development is predicted to exceed 80 % across most of the southern prairies (Fig. 2).

Figure 1. Predicted percent embryonic development of grasshopper eggs across the Canadian prairies as of May 30, 2021.

Figure 2. Predicted grasshopper (Melanoplus sanguinipes) embryological development (%) across the Canadian prairies as of May 30, 2021.

First hatchlings usually are observed once eggs reach 80 % development. As of May 30, hatch was predicted to be occurring across most of the prairies with hatch rates approaching 15-20 % across southern Manitoba and Saskatchewan (Fig. 3).

Figure 3. Predicted grasshopper (Melanoplus sanguinipes) hatch (%) across the Canadian prairies as of May 30, 2021.

The model was projected to June 15 to determine potential development at Saskatoon and Brandon over the next two weeks (Figs. 4 and 5). Results suggest that by June 15 hatch could be greater than 65 % at both locations and nymph populations will consist of first, second, and third instars. Drought conditions tend to favour the development of grasshopper populations while delaying crop development. If dry conditions persist, crop development may be delayed across Manitoba. This may result in conditions conducive to crop damage from grasshoppers as hatch progresses in June. Monitor roadsides and field margins to assess the development and densities of local grasshopper populations.

Figure 4. Predicted development of M. sanguinipes populations near Saskatoon, Saskatchewan as of May 30, 2021 (projected to June 15, 2021).

Figure 5. Predicted development of M. sanguinipes populations near Brandon, Manitoba as of May 30, 2021 (projected to June 15, 2021).

Predicted grasshopper development

Model simulations were used to estimate grasshopper egg development as of May 23, 2021. Average development of eggs is 73 % and is well ahead of the long-term average of 62 %. Since last week, developmental rates increased at all locations. Recent warm conditions across southeastern Saskatchewan and southern Manitoba have been responsible for the advanced development of eggs near Regina, Brandon and Winnipeg (Fig. 1). The simulation predicted that development was greatest across most of the southern prairies (Fig. 2).

Figure 1. Predicted percent embryonic development of grasshopper eggs (*Melanoplus sanguinipes*) across
the Canadian prairies **as of May 23, 2021**.

Figure 2. Predicted grasshopper (*Melanoplus sanguinipes*) embryological development across the Canadian prairies **as of May 23, 2021**.

The model was projected to June 7 to determine potential development at Winnipeg and Lethbridge over the next two weeks (Figs. 3 and 4). Results suggest that by June 7 hatch could be at 20 % for Lethbridge and approximately 35 % near Winnipeg. Drought conditions tend to favour development of grasshopper populations while delaying crop development. If dry conditions persist, crop development may be delayed across Manitoba. This may result in conditions conducive to crop damage from grasshoppers as the hatch progresses in late May and early June.

Figure 3. Projected predicted development of *M. sanguinipes* populations near Winnipeg, Manitoba as of May 23, 2021 (projected to June 7, 2021).

Figure 4. Projected predicted development of M. sanguinipes populations near Lethbridge, Alberta as of May 23, 2021 (projected to June 7, 2021).

Predicted grasshopper development

Model simulations were used to estimate percent grasshopper egg development as of May 16, 2021. Average development of eggs is 68 % and is well ahead of the long term average of 59 %. Since last week, developmental rates have increased at all locations (Fig. 1). The simulation predicts that development is greatest in the region that includes Regina, Saskatoon and Lethbridge (Fig. 2).

Figure 1. Predicted percent embryonic development of grasshopper eggs across the Canadian prairies as of May 16, 2021.

Figure 2. Predicted grasshopper (Melanoplus sanguinipes) embryological development across the Canadian prairies as of May 16, 2021.

Recent warm temperatures near Winnipeg have resulted in faster development rates. The model was projected to May 31 to determine potential development at Saskatoon and Regina (Figs. 3 and 4). Results suggest that initial hatch may occur in the next few days with increased hatch occurring in late May. Current drought conditions tend to favour development of grasshopper populations while delaying crop development. Crop development may be delayed across southern and central regions of Saskatchewan. This may result in conditions conducive for crop damage from grasshoppers as hatch progresses in late May and early June.

Figure 3. Projected predicted development of *M. sanguinipes* populations near Regina SK as of May 16, 2021 (**projected to May 31, 2021**).

Figure 4. Projected predicted development of M. sanguinipes populations near Saskatoon SK as of May 16, 2021 (projected to May 31, 2021).

Predicted grasshopper development

Model simulations were used to estimate percent grasshopper embryonic (egg) development as of May 9, 2021. The simulation predicts that development has now begun across southern areas of the Peace River region. Results indicate that egg development has been greatest for Lethbridge and Regina regions. Cool conditions in Manitoba have resulted in slower development rates (Figs. 1 and 2).

**Figure 1**. Predicted grasshopper (*Melanoplus sanguinipes*) embryological development across the Canadian prairies as of May 9, 2021.

**Figure 2**. Predicted percent embryonic development of overwintered grasshopper eggs across the Canadian prairies as of May 9, 2021.

Predicted grasshopper development

Grasshopper Simulation Model Output – The grasshopper simulation model will be used to monitor grasshopper development across the prairies. Weekly temperature data collected across the prairies is incorporated into the simulation model which calculates estimates of grasshopper development stages based on biological parameters for Melanoplus sanguinipes (Migratory grasshopper).

Model simulations were used to estimate percent grasshopper embryonic development as of May 2, 2021. Results indicate that egg development has begun across the southern prairies (Fig. 1) and progression estimates for sites across the prairies are presented in Figure 2.

Figure 1. Predicted grasshopper (*Melanoplus sanguinipes*) embryological development across the Canadian prairies as of May 2, 2021.

Figure 2. Predicted percent embryonic development of overwintered grasshopper eggs across the Canadian prairies as of May 2, 2021.

Predicted grasshopper development

As of July 12, 2020, the grasshopper model estimates that development across the prairies ranges from 1st instar stage to adults. Based on the model simulations, development has been slowest in the Peace River region where average nymph development ranges between the 2nd and 3rd instars (Fig. 1; Table 1). Across the southern prairies, the majority of the nymph population is predicted to be in the 3rd to 5th instar stages, with adults predicted to occur across southern Manitoba where populations are active (Fig. 1; Table 1). Across the prairies, populations are predicted to be 6, 6, 11, 27, 24, 21 and 5% in egg, first, second, third, fourth, fifth and adult stages, respectively.

**Figure 1**. Predicted average instar stages of grasshopper (*Melanoplus sanguinipes*) populations across the Canadian prairies (as of July 12, 2020).

Table 1 indicates that predicted development at Brandon and Winnipeg is well ahead of Lacombe and Grande Prairie. The two graphs compare grasshopper development in Saskatoon (Fig. 2) and Winnipeg (Fig. 3). Grasshopper populations near Saskatoon are predominantly in the 4th and 5th instars with first appearance of adults beginning to occur (Fig. 2). Populations near Winnipeg are expected to be primarily adults (Fig. 3).

**Figure 2**. Predicted grasshopper (*Melanoplus sanguinipes*) phenology at Saskatoon SK. Values are based on model simulations (April 1-July 12, 2020).

**Figure** 3. Predicted grasshopper (*Melanoplus sanguinipes*) phenology at Winnipeg MB. Values are based on model simulations (April 1-July 12, 2020).

Biological and monitoring information related to grasshoppers in field crops is posted by Manitoba Agriculture, Saskatchewan Agriculture, Alberta Agriculture and Forestry, the BC Ministry of Agriculture and the Prairie Pest Monitoring Network. Also refer to the grasshopper pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (Philip et al. 2018) as an English-enhanced or French-enhanced version.