Tag: Mamestra configurata

Predicted bertha armyworm development

The phenology model for bertha armyworm development on the Canadian prairies was developed by Ross Weiss and Owen Olfert. Model simulations were used to estimate development of bertha armyworm as of June 22, 2025.

The model outputs predict that bertha armyworm populations, where present, should consist mainly of adults laying eggs (Fig. 1). Based on the model outputs, populations throughout most of Alberta and Saskatchewan are predicted to be mainly be in the egg stage (as of June 22, 2025). In some areas south of Winnipeg, east of Lethbridge, and northeast of Swift Current, larvae may be present (Fig. 2).

Figure 1. The proportion of the (Mamestra configurata) population that is predicted to be in the EGG stage (% of total population) across the Canadian prairies as of June 22, 2025.
Figure 2. The proportion of the (Mamestra configurata) population that is predicted to be in the LARVAL stage (% of total population) across the Canadian prairies as of June 22, 2025.

Figure 3 includes photos of the various life stages of the bertha armyworm. There is one generation per year and pupae overwinter in the soil (Fig. 3, C). Each growing season, green unitraps utilizing pheromone lures are deployed and checked weekly over a 6-week window. Cumulative counts generated from the pheromone traps are used to estimate subsequent bertha armyworm densities. The cumulative moth count data is compiled using geospatial maps then posted to support and time in-field scouting for damaging populations of larvae by mid-July through to August.

Figure 3. Stages of bertha armyworm from egg (A), larva (B), pupa (C), to adult (D). Photos: J. Williams (Agriculture and Agri-Food Canada).

Please refer to this week’s Provincial Insect Pest Report Links to find the most up-to-date information summarizing weekly cumulative counts compiled by provincial pheromone trapping networks across the Canadian prairies in 2025. For example, Manitoba Agriculture’s June 19th Crop Pest Report includes Figure 4 with a reminder that other moth species are actively flying now so examine wing colourations and patterning carefully when checking the contents of bertha armyworm pheromone traps! Clover cutworm can be common by-catch in pheromone traps designed to monitor bertha armyworm, but also those designed to monitor true armyworm.

Figure 4. Comparison of diagnostic wing features of three moth species. Images and information all courtesy of Manitoba Agriculture, J. Gavloski who originally included in the June 19, 2025, issue of the Manitoba Crop Pest Update.

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm 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 Field Guides page. Also consider reviewing this 2019 Insect of the Week featuring bertha armyworm and its doppelganger, the clover cutworm! 

Predicted bertha armyworm development

The phenology model for bertha armyworm development on the Canadian prairies was developed by Ross Weiss and Owen Olfert. Model simulations were used to estimate development of bertha armyworm as of June 15, 2025.

The model indicates that in areas where bertha armyworm populations are present, the population should consist mainly of adults (Fig. 1). Based on the model readings, the percentage of adult berth armyworm in the population should be highest in Alberta and Saskatchewan. In some areas south of Winnipeg, east of Lethbridge, and northeast of Swift Current, the model predicts that female moths are already laying eggs (Fig. 2).

Figure 1. The proportion of the (Mamestra configurata) population that is predicted to be in the adult stage (% of total population) across the Canadian prairies as of June 15, 2025.
Figure 2. The proportion of the (Mamestra configurata) population that is predicted to be in the egg stage (% of total population) across the Canadian prairies as of June 15, 2025.

Figure 3 includes photos of the various life stages of the bertha armyworm. There is one generation per year and pupae overwinter in the soil (Fig. 3, C). Each growing season, green unitraps utilizing pheromone lures are deployed and checked weekly over a 6-week window. Cumulative counts generated from the pheromone traps are used to estimate subsequent bertha armyworm densities. The cumulative moth count data is compiled using geospatial maps then posted to support and time in-field scouting for damaging populations of larvae by mid-July through to August.

Figure 3. Stages of bertha armyworm from egg (A), larva (B), pupa (C), to adult (D). Photos: J. Williams (Agriculture and Agri-Food Canada).

Please refer to this week’s Provincial Insect Pest Report Links to find the most up-to-date information summarizing weekly cumulative counts compiled by provincial pheromone trapping networks across the Canadian prairies in 2025. For example, Manitoba Agriculture’s June 19th Crop Pest Report includes Figure 4 with a reminder that other moth species are actively flying now so examine wing colourations and patterning carefully when checking the contents of bertha armyworm pheromone traps! Clover cutworm can be common by-catch in pheromone traps designed to monitor bertha armyworm, but also those designed to monitor true armyworm.

Figure 4. Comparison of diagnostic wing features of three moth species. Images and information all courtesy of Manitoba Agriculture, J. Gavloski who originally included in the June 19, 2025, issue of the Manitoba Crop Pest Update.

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm 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. Also consider reviewing this 2019 Insect of the Week featuring bertha armyworm and its doppelganger, the clover cutworm! 

Predicted bertha armyworm development

The phenology model for bertha armyworm development on the Canadian prairies was developed by Ross Weiss and Owen Olfert. Model simulations were used to estimate development of bertha armyworm as of June 8, 2025. Model outputs predict that the adult flight has likely started in most areas where bertha armyworm populations are present except for in parts of the BC Peace River region and along the foothills in western Alberta where the percentage of the population in the adult stage is estimated to be less than 15 % (Fig. 1). Based on the model readings, the percentage of bertha armyworm in the adult stage, where populations are present, should be highest in areas between Edmonton and Calgary in Alberta.

Figure 1. The proportion of the (Mamestra configurata) population that is predicted to be in the adult stage (% of total population) across the Canadian prairies as of June 8, 2025.

Figure 2 includes photos of the various life stages of the bertha armyworm. There is one generation per year and pupae overwinter in the soil (Fig. 2, C). Each growing season, green unitraps utilizing pheromone lures are deployed and checked weekly over a 6-week window. Cumulative counts generated from the pheromone traps are used to estimate subsequent bertha armyworm densities. The cumulative moth count data is compiled using geospatial maps then posted to support and time in-field scouting for damaging populations of larvae by mid-July through to August.

Figure 2. Stages of bertha armyworm from egg (A), larva (B), pupa (C), to adult (D). Photos: J. Williams (Agriculture and Agri-Food Canada).

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm 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. Also consider reviewing the 2019 Insect of the Week, which featured bertha armyworm and its doppelganger, the clover cutworm! 

Bertha armyworm

Degree-days can be used to predict the timing of insect development and plan for pest scouting and management.  Degree-days are calculated for different insect species using temperature thresholds specific to their development. Based on research, the temperature threshold for bertha armyworm (Mamestra configurata) development is 7 °C and 352 accumulated degree-days (base 7 °C) are required for overwintered pupae to begin their spring development phase. As of May 25, there are no areas on the prairies that have surpassed the degree-day requirement for pupal development of bertha armyworm (Fig. 1).

Figure 1. Growing degree-day heat units (Base 7 °C) accumulated across the Canadian prairies from April 1 to May 25, 2025.

Pheromone traps used to monitor bertha armyworm are typically set up along canola fields when pupal development reaches 75-80%; the 2024 monitoring season started the week of June 10, 2024. Cumulative counts from sentinel pheromone monitoring sites targeting bertha armyworm moths across the Canadian prairies in 2024 are highlighted as geospatial areas where producers are encouraged to prioritize in-field monitoring in 2025. Areas in Figure 2 highlighted yellow, orange, or especially red hosted pheromone traps that intercepted relatively high cumulative counts of moths in 2024 and should be prioritized for in-field scouting in 2025. Review the prairie-wide historical survey maps for this insect species.

Figure 2. Cumulative weekly counts of Bertha armyworm (Mamestra configurata) moths arising from the 2024 growing season.

Figure 3 includes photos of the various life stages of the bertha armyworm. There is one generation per year and pupae overwinter in the soil (Fig. 3, C). Each growing season, green unitraps utilizing pheromone lures are deployed and checked weekly over a 6-week window. Cumlative counts generated from the pheromone traps are used to estimate subsequent bertha armyworm densities. The cumulative moth count data is compiled using geospatial maps then posted to support and time in-field scouting for damaging populations of larvae by mid-July through to August.

Figure 3. Stages of bertha armyworm from egg (A), larva (B), pupa (C), to adult (D). Photos: J. Williams (Agriculture and Agri-Food Canada).

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm 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. Also consider reviewing the 2019 Insect of the Week, which featured bertha armyworm and its doppelganger, the clover cutworm! 

Bertha armyworm

Degree-days can be used to predict the timing of insect development and plan for pest scouting and management.  Degree-days are calculated for different insect species using temperature thresholds specific to their development. Based on research, the temperature threshold for bertha armyworm (Mamestra configurata) development is 7 °C and 352 accumulated degree-days (base 7 °C) are required for overwintered pupae to begin their spring development phase. As of May 25, there are no areas on the prairies that have surpassed the degree-day requirement for pupal development of bertha armyworm (Fig. 1).

Figure 1. Growing degree-day heat units (Base 7 °C) accumulated across the Canadian prairies from April 1 to May 25, 2025.

Pheromone traps used to monitor bertha armyworm are typically set up along canola fields when pupal development reaches 75-80%; the 2024 monitoring season started the week of June 10, 2024. Cumulative counts from sentinel pheromone monitoring sites targeting bertha armyworm moths across the Canadian prairies in 2024 are highlighted as geospatial areas where producers are encouraged to prioritize in-field monitoring in 2025. Areas in Figure 2 highlighted yellow, orange, or especially red hosted pheromone traps that intercepted relatively high cumulative counts of moths in 2024 and should be prioritized for in-field scouting in 2025. Review the prairie-wide historical survey maps for this insect species.

Figure 2. Cumulative weekly counts of Bertha armyworm (Mamestra configurata) moths arising from the 2024 growing season.

Figure 3 includes photos of the various life stages of the bertha armyworm. There is one generation per year and pupae overwinter in the soil (Fig. 3, C). Each growing season, green unitraps utilizing pheromone lures are deployed and checked weekly over a 6-week window. Cumlative counts generated from the pheromone traps are used to estimate subsequent bertha armyworm densities. The cumulative moth count data is compiled using geospatial maps then posted to support and time in-field scouting for damaging populations of larvae by mid-July through to August.

Figure 3. Stages of bertha armyworm from egg (A), larva (B), pupa (C), to adult (D). Photos: J. Williams (Agriculture and Agri-Food Canada).

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm 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. Also consider reviewing the 2019 Insect of the Week, which featured bertha armyworm and its doppelganger, the clover cutworm! 

Bertha armyworm

Degree-days can be used to predict the timing of insect development and plan for pest scouting and management.  Degree-days are calculated for different insect species using temperature thresholds specific to their development. Based on research, the temperature threshold for bertha armyworm (Mamestra configurata) development is 7 °C and 352 accumulated degree-days (base 7 °C) are required for overwintered pupae to begin their spring development phase. As of May 18, much of the prairies has not reached the degree-day requirement for pupal development of bertha armyworm (Fig. 1).

Figure 1. Growing degree-day heat units (Base 7 °C) accumulated across the Canadian prairies as of May 18, 2025.

Pheromone traps used to monitor bertha armyworm are typically set up along canola fields when pupal development reaches 75-80%; the 2024 monitoring season started the week of June 10, 2024.

Figure 2 includes photos of the various life stages of the bertha armyworm. There is one generation per year and pupae overwinter in the soil (Fig. 2, C). Each growing season, green unitraps utilizing pheromone lures are deployed and checked weekly over a 6-week window. Cumlative counts generated from the pheromone traps are used to estimate subsequent bertha armyworm densities. The cumulative moth count data is compiled using geospatial maps then posted to support and time in-field scouting for damaging populations of larvae by mid-July through to August.

Figure 2. Stages of bertha armyworm from egg (A), larva (B), pupa (C), to adult (D). Photos: J. Williams (Agriculture and Agri-Food Canada).

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm 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. Also consider reviewing the 2019 Insect of the Week which featured bertha armyworm and its doppelganger, the clover cutworm! 

Bertha armyworm

Access the Provincial Insect Pest Report for Wk16 for updates for this economic insect pest.

Remember: in-field scouting is required to apply the economic threshold to manage both this pest and its natural enemies. Use the images below (Fig. 1) to help identify moths from the by-catch that will be retained in the green phermone-baited unitraps.

Figure 1. Stages of bertha armyworm from egg (A), larva (B), pupa (C), to adult (D). Photos: J. Williams (Agriculture and Agri-Food Canada).

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting or review the 2024 Insect of the Week featuring bertha armyworm. Also scan over the 2019 Insect of the Week featuring bertha armyworm and its doppelganger, the clover cutworm! 

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm 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.

Bertha armyworm

Access the Provincial Insect Pest Report for Wk14 for updates for this economic insect pest.

Remember: in-field scouting is required to apply the economic threshold to manage both this pest and its natural enemies. Use the images below (Fig. 1) to help identify moths from the by-catch that will be retained in the green phermone-baited unitraps.

Figure 1. Stages of bertha armyworm from egg (A), larva (B), pupa (C), to adult (D). Photos: J. Williams (Agriculture and Agri-Food Canada).

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting or review the 2024 Insect of the Week featuring bertha armyworm. Also scan over the 2019 Insect of the Week featuring bertha armyworm and its doppelganger, the clover cutworm! 

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm 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.

Bertha armyworm

Weekly Pheromone-baited Trapping Results – Early season detection of bertha armyworm is improved through the use of pheromone-baited unitraps traps deployed in fields across the Canadian prairies. Access the Provincial Insect Pest Report for Wk12 for updates for this economic insect pest.

Remember: in-field scouting is required to apply the economic threshold to manage both this pest and its natural enemies. Use the images below (Fig. 1) to help identify moths from the by-catch that will be retained in the green phermone-baited unitraps.

Figure 1. Stages of bertha armyworm from egg (A), larva (B), pupa (C), to adult (D). Photos: J. Williams (Agriculture and Agri-Food Canada).

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting or review the 2024 Insect of the Week featuring bertha armyworm. Also scan over the 2019 Insect of the Week featuring bertha armyworm and its doppelganger, the clover cutworm! 

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm 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.

Bertha armyworm

Weekly Pheromone-baited Trapping Results – Early season detection of bertha armyworm is improved through the use of pheromone-baited unitraps traps deployed in fields across the Canadian prairies. Access the Provincial Insect Pest Report for Wk09 for updates for this economic insect pest.

Remember: in-field scouting is required to apply the economic threshold to manage both this pest and its natural enemies. Use the images below (Fig. 1) to help identify moths from the by-catch that will be retained in the green phermone-baited unitraps.

Figure 1. Stages of bertha armyworm from egg (A), larva (B), pupa (C), to adult (D). Photos: J. Williams (Agriculture and Agri-Food Canada).

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting or review the 2024 Insect of the Week featuring bertha armyworm. Also scan over the 2019 Insect of the Week featuring bertha armyworm and its doppelganger, the clover cutworm! 

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm 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.

Bertha armyworm

Weekly Pheromone-baited Trapping Results – Early season detection of bertha armyworm is improved through the use of pheromone-baited unitraps traps deployed in fields across the Canadian prairies. Access the Provincial Insect Pest Report for Wk09 for updates for this economic insect pest.

Remember: in-field scouting is required to apply the economic threshold to manage both this pest and its natural enemies. Use the images below (Fig. 1) to help identify moths from the by-catch that will be retained in the green phermone-baited unitraps.

Figure 1. Stages of bertha armyworm from egg (A), larva (B), pupa (C), to adult (D). Photos: J. Williams (Agriculture and Agri-Food Canada).

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting or review the 2024 Insect of the Week featuring bertha armyworm. Also scan over the 2019 Insect of the Week featuring bertha armyworm and its doppelganger, the clover cutworm! 

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm 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.

Bertha armyworm

Weekly Pheromone-baited Trapping Results – Early season detection of bertha armyworm is improved through the use of pheromone-baited unitraps traps deployed in fields across the Canadian prairies. Please refer to this week’s Provincial Insect Pest Report Links to find the most up-to-date information summarizing weekly cumulative counts compiled by provincial pheromone trapping networks across the Canadian prairies in 2024.

Remember: in-field scouting is required to apply the economic threshold to manage both this pest and its natural enemies. Use the images below (Fig. 1) to help identify moths from the by-catch that will be retained in the green phermone-baited unitraps.

Figure 1. Stages of bertha armyworm from egg (A), larva (B), pupa (C), to adult (D). Photos: J. Williams (Agriculture and Agri-Food Canada).

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting or review the 2024 Insect of the Week featuring bertha armyworm. Also scan over the 2019 Insect of the Week featuring bertha armyworm and its doppelganger, the clover cutworm! 

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm 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.

Bertha armyworm

Pheromone traps used to monitor bertha armyworm are typically set up along canola fields when pupal development reaches 75-80%; the 2024 monitoring season started the week of June 10, 2024. Use the images below (Fig. 1) to help identify moths from the by-catch that will be retained in the green phermone-baited unitraps.

Figure 1. Stages of bertha armyworm from egg (A), larva (B), pupa (C), to adult (D). Photos: J. Williams (Agriculture and Agri-Food Canada).

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting or review the 2024 Insect of the Week featuring bertha armyworm. Also scan over the 2019 Insect of the Week featuring bertha armyworm and its doppelganger, the clover cutworm! 

Please refer to this week’s Provincial Insect Pest Report Links to find the most up-to-date information summarizing weekly cumulative counts compiled by provincial pheromone trapping networks across the Canadian prairies in 2024.

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm 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.

Bertha armyworm

Pheromone traps used to monitor bertha armyworm are typically set up along canola fields when pupal development reaches 75-80%; the 2024 monitoring season started the week of June 10, 2024.

Use the images below (Fig. 1) to help identify moths from the by-catch that will be retained in the green phermone-baited unitraps.

Figure 1. Stages of bertha armyworm from egg (A), larva (B), pupa (C), to adult (D). Photos: J. Williams (Agriculture and Agri-Food Canada).

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting or review the 2019 Insect of the Week which featured bertha armyworm and its doppelganger, the clover cutworm! 

Please refer to this week’s Provincial Insect Pest Report Links to find the most up-to-date information summarizing weekly cumulative counts compiled by provincial pheromone trapping networks across the Canadian prairies in 2024.

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm 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.

Bertha armyworm

Pheromone traps used to monitor bertha armyworm are typically set up along canola fields when pupal development reaches 75-80%; the 2024 monitoring season started the week of June 10, 2024.

Use the images below (Fig. 1) to help identify moths from the by-catch that will be retained in the green phermone-baited unitraps.

Figure 1. Stages of bertha armyworm from egg (A), larva (B), pupa (C), to adult (D). Photos: J. Williams (Agriculture and Agri-Food Canada).

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting or review the 2019 Insect of the Week which featured bertha armyworm and its doppelganger, the clover cutworm! 

Please refer to this week’s Provincial Insect Pest Report Links to find the most up-to-date information summarizing weekly cumulative counts compiled by provincial pheromone trapping networks across the Canadian prairies in 2024.

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm 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.

Bertha armyworm

Pheromone traps used to monitor bertha armyworm are typically set up along canola fields when pupal development reaches 75-80%; the 2024 monitoring season will start soon with traps due to be set up the week of June 10, 2024.

Use the images below (Fig. 1) to help identify moths from the by-catch that will be retained in the green phermone-baited unitraps.

Figure 1. Stages of bertha armyworm from egg (A), larva (B), pupa (C), to adult (D). Photos: J. Williams (Agriculture and Agri-Food Canada).

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting or review the 2019 Insect of the Week which featured bertha armyworm and its doppelganger, the clover cutworm! 

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm 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.

Bertha armyworm

Based on long-term data for the prairie region, bertha armyworm pupal development should be 30-75% completed by late May in a normal year (Fig. 1).

Figure 1. Long-term average predicted bertha armyworm (Mamestra configurata) pupal development (% completion) across the Canadian prairies as of May 28, 2023. Model runs were conducted using climate normal data.

Pheromone traps used to monitor bertha armyworm are typically set up along canola fields when pupal development reaches 75-80%; the 2024 monitoring season will be starting soon, with traps likely to be set up the week of June 10, 2024.

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting or review the 2019 Insect of the Week which featured bertha armyworm and its doppelganger, the clover cutworm! 

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm 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.

Predicted bertha armyworm development

Compared to long-term averages, bertha armyworm (BAW) development has been delayed thus far in the 2022 growing season. Pupal BAW development is progressing across the prairies. This week, pupal development is predicted to complete and adult emergence is expected to occur across most of the prairies (Fig. 1). Adult emergence should have already begun across a region extending from Lethbridge to Regina and north to Saskatoon. Adult emergence near Regina, Saskatchewan (Fig. 2) is predicted to be one week ahead of central Alberta (Fig. 3). Oviposition should begin over the next 7-10 days.

Figure 1. Predicted bertha armyworm (Mamestra configurata) pupal development (%) across the Canadian prairies as of June 19, 2022.
Figure 2. Predicted bertha armyworm (Mamestra configurata) populations near Regina, Saskatchewan as of June 19, 2022 (projected to June 30, 2022, based on long-term average conditions).
Figure 3. Predicted bertha armyworm (Mamestra configurata) populations near Lacombe, Alberta as of June 19, 2022 (projected to June 30, 2022, based on long-term average conditions).

Use the images below (Fig. 4) to help identify moths from the by-catch that will be retained in the green phermone-baited unitraps.

Figure 4. Stages of bertha armyworm from egg (A), larva (B), pupa (C) to adult (D).
Photos: J. Williams (Agriculture and Agri-Food Canada)

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting or review the 2019 Insect of the Week which featured bertha armyworm and its doppelganger, the clover cutworm! 

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm 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.

Predicted bertha armyworm development

Pupal development of bertha armyworm (BAW) is progressing across the prairies with the most rapid development occurring across southern and central regions of Alberta and western Saskatchewan (Fig. 1). Over the next week, adults should be emerging across Alberta, Saskatchewan and localized areas in southern Manitoba.

Figure 1. Predicted bertha armyworm (Mamestra configurata) pupal development (%) across the Canadian prairies as of June 12, 2022.

Use the images below (Fig. 2) to help identify moths from the by-catch that will be retained in the green phermone-baited unitraps.

Figure 2. Stages of bertha armyworm from egg (A), larva (B), pupa (C) to adult (D).
Photos: J. Williams (Agriculture and Agri-Food Canada)

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting or review the 2019 Insect of the Week which featured bertha armyworm and its doppelganger, the clover cutworm! 

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm 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.

Predicted bertha armyworm development

Compared to average development, bertha armyworm (BAW) pupal development in 2022 continues to be delayed for the Peace River region, Manitoba and southern and eastern regions of Saskatchewan (Fig. 1). Pupal development across southern and central Alberta and Saskatchewan is similar to long-term average values. Development in this region is 60-75% complete.

We suggest that BAW pheromone traps be placed in fields when pupal development is 75-80% to ensure that traps are in place prior to emergence of adults. Based on current runs, it is advisable that traps for Alberta and Saskatchewan be placed in fields by the end of this week (June 6-10). Traps should be put out in Manitoba and the Peace River region next week.

Figure 1. Predicted bertha armyworm (Mamestra configurata) pupal development (%) across the Canadian prairies as of June 5, 2022.

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting or eview the 2019 Insect of the Week which featured bertha armyworm and its doppelganger, the clover cutworm! 

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm 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.

Predicted bertha armyworm development

When considering average versus in-season pupal development, the current 2022 development of overwintered BAW pupae is expected to be significantly delayed for the Peace River region, Manitoba, and southern and eastern regions of Saskatchewan (Fig. 1). Though somewhat delayed, development of BAW pupae in southern and central Alberta and western Saskatchewan will be similar to average.

We recommend BAW pheromone traps be placed in fields when pupal development is 75-80 % to ensure traps are deployed in advance of the emergence of adults. The weather forecast predicts normal temperatures for the next week. This should advance BAW development with rates becoming similar to long-term average values. Based on current runs, it is advisable that Alberta and Saskatchewan traps be placed in fields by the end of next week (June 6-10). Traps in MB and the Peace River region should be put out one (Manitoba) or two (Peace River region) weeks later.

Figure 1. Predicted bertha armyworm (Mamestra configurata) pupal development (%) across the Canadian prairies as of May 29, 2022.

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting or review the 2019 Insect of the Week which featured bertha armyworm and its doppelganger, the clover cutworm! 

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm 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.

Bertha armyworm

Provincial insect pest monitoring networks in Manitoba, Saskatchewan and Alberta are now compiling cumulative counts of adults intercepted from the pheromone-baited green unitraps deployed in fields across the prairies. Review the Provincial Insect Pest Report Links to find summaries or link to the latest bertha armyworm moth counts by clicking the appropriate province’s reporting info for Manitoba, Saskatchewan or Alberta. So far, interception counts remain mainly in the “low risk” categories across the Canadian prairies. Review the 2020 pheromone trapping cumulative moth counts here to identify potential high risk areas to target for scouting for larvae now!

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting.  Use the images below (Fig. 1) to help identify the various stages.  Review the 2019 Insect of the Week which featured bertha armyworm and its doppelganger, the clover cutworm! 

This image has an empty alt attribute; its file name is 2019_PPMN-Protocol_BAW_LifeStages_Williams.png
Figure 6. The egg stage (A), larval stage (B), pupal stage (C), and adult stage (D) of bertha armyworm. Photos: Jonathon Williams (AAFC-Saskatoon).

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” which is a free downloadable document as both an English-enhanced or French-enhanced version.

Predicted bertha armyworm development

Model simulations to June 27, 2021 indicate that development of bertha armyworm (BAW) (Mamestra configurata) populations is transitioning to egg and larval stages. Model simulations indicate that BAW oviposition is occurring across most of the prairies with occurrence of larvae across southern regions of all three provinces (Figs. 1 and 2).

Figure 1. Predicted percent of bertha armyworm (Mamestra configurata) population that is in the egg stage (% of population) across the Canadian prairies as of June 27, 2021.
Figure 2. Predicted percent of bertha armyworm (Mamestra configurata) population that is in the larval stage (% of population) across the Canadian prairies as of June 27, 2021.

BAW populations in southern Manitoba are predicted to be predominantly in the larval stage by early July whereas BAW populations near Grande Prairie will be in the adult and egg stages. Model projections to July 13 predict that development near Brandon will be more advanced than development near Lacombe (Figs. 3 and 4). Over the next few days adult populations should be declining in southern Manitoba. In central Alberta adults should continue to lay eggs over the next 10 days. Above average temperatures will result in rapid development of larval populations.

Figure 3. Predicted development of bertha armyworm (Mamestra configurata) populations near Brandon, Manitoba as of June 27, 2021 (projected to July 13, 2021).
Figure 4. Predicted development of bertha armyworm (Mamestra configurata) populations near Lacombe, Alberta as of June 27, 2021 (projected to July 13, 2021).

Provincial insect pest monitoring networks in Manitoba, Saskatchewan and Alberta are now compiling cumulative counts of adults intercepted from the pheromone-baited green unitraps deployed in fields across the prairies. Review the Provincial Insect Pest Report Links to find summaries or link to the latest bertha armyworm moth counts by clicking the appropriate province’s reporting info for Manitoba, Saskatchewan or Alberta.

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting.  Use the images below (Fig. 6) to help identify the various stages.  Review the 2019 Insect of the Week which featured bertha armyworm and its doppelganger, the clover cutworm! 

This image has an empty alt attribute; its file name is 2019_PPMN-Protocol_BAW_LifeStages_Williams.png
Figure 6. The egg stage (A), larval stage (B), pupal stage (C), and adult stage (D) of bertha armyworm. Photos: Jonathon Williams (AAFC-Saskatoon).

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” which is a free downloadable document as both an English-enhanced or French-enhanced version.

Predicted bertha armyworm development

Model simulations to June 20, 2021, indicate that the development of bertha armyworm (BAW) (Mamestra configurata) pupae are nearly complete. Other than the Peace River region, BAW adults should now be active across the prairies (Fig. 1). Model simulations indicate that BAW oviposition has begun across southern areas of Manitoba, Saskatchewan and localized areas in Alberta (Fig. 2).

Figure 1. Predicted percent of bertha armyworm (Mamestra configurata) population that is in the adult stage (% of population) across the Canadian prairies as of June 20, 2021.
Figure 2. Predicted percent of bertha armyworm (Mamestra configurata) population that is in the egg stage (% of population) across the Canadian prairies as of June 20, 2021.

Model projections to July 6 predict that development near Brandon will be more advanced than development near Grande Prairie (Figs. 3 and 4). BAW populations in southern Manitoba are predicted to be predominantly in the larval stage by early July whereas BAW populations near Grande Prairie will be in the adult and egg stages.

Figure 3. Predicted development of bertha armyworm (Mamestra configurata) populations near Brandon, Manitoba as of June 20, 2021 (projected to July 6, 2021).
Figure 4. Predicted development of bertha armyworm (Mamestra configurata) populations near Grande Prairie, Alberta as of June 20, 2021 (projected to July 6, 2021).

Provincial insect pest monitoring networks in Manitoba, Saskatchewan and Alberta are now compiling cumulative counts of adults intercepted from the pheromone-baited green unitraps deployed in fields across the prairies. Review the Provincial Insect Pest Report Links to find summaries or link to the latest bertha armyworm moth counts by clicking the appropriate province’s reporting info for Manitoba, Saskatchewan or Alberta.

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting.  Use the images below (Fig. 6) to help identify the various stages.  Review the 2019 Insect of the Week which featured bertha armyworm and its doppelganger, the clover cutworm! 

This image has an empty alt attribute; its file name is 2019_PPMN-Protocol_BAW_LifeStages_Williams.png
Figure 6. The egg stage (A), larval stage (B), pupal stage (C), and adult stage (D) of bertha armyworm. Photos: Jonathon Williams (AAFC-Saskatoon).

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” which is a free downloadable document as both an English-enhanced or French-enhanced version.

Predicted bertha armyworm development

Model simulations to June 13, 2021, indicate that bertha armyworm (BAW) (Mamestra configurata) pupal development is greater than 75% (Fig. 1). Populations are predominantly in the pupal stage (Fig. 2).

Figure 1. Predicted bertha armyworm (Mamestra configurata) pupal development (%) across the Canadian prairies as of June 13, 2021.
Figure 2. Predicted percent of bertha armyworm (Mamestra configurata) population that is in the pupal stage (% of population) across the Canadian prairies as of June 13, 2021.

Model simulations indicate that BAW adult emergence has begun across southern areas of Manitoba and Saskatchewan (Fig. 3). Based on pupal development, adult emergence should occur across most of the prairies over the next few days.

Figure 3. Predicted percent of bertha armyworm (Mamestra configurata) population that is in the adult stage (% of population) across the Canadian prairies as of June 13, 2021.

Model projections to June 30 predict that development near Winnipeg is more advanced than at Lacombe (Figs. 4 and 5). The model predicts that oviposition has begun near Winnipeg and that egg hatch will begin next week in fields.

Figure 4. Predicted development of bertha armyworm (Mamestra configurata) populations near Winnipeg, Manitoba as of June 13, 2021 (projected to June 29, 2021).
Figure 5. Predicted development of bertha armyworm (Mamestra configurata) populations near Lacombe, Alberta as of June 13, 2021 (projected to June 29, 2021).

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting.  Use the images below (Fig. 6) to learn to identify the various stages.  Review the 2019 Insect of the Week which featured bertha armyworm and its doppelganger, the clover cutworm! 

This image has an empty alt attribute; its file name is 2019_PPMN-Protocol_BAW_LifeStages_Williams.png
Figure 6. The egg stage (A), larval stage (B), pupal stage (C), and adult stage (D) of bertha armyworm. Photos: Jonathon Williams (AAFC-Saskatoon).

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” which is a free downloadable document as both an English-enhanced or French-enhanced version.

Predicted bertha armyworm development

Model simulations to June 6, 2021, indicate that bertha armyworm (BAW) (Mamestra configurata) pupal development ranges from 60-90 % across the prairies (Fig. 1). BAW traps should be placed in fields when pupal development exceeds 80 %. Table 1 provides guidelines to determine when traps should be deployed. Based on weather data up to June 6, 2021, BAW adults should begin to emerge by mid to late June.

Figure 1. Predicted bertha armyworm (Mamestra configurata) pupal development across the Canadian prairies as of June 6, 2021.

Model projections to June 30 predict that development near Winnipeg will be more advanced than at Lacombe (Figs. 2 and 3, respectively). The model predicts that egg hatch will begin in mid-June near Winnipeg.

Figure 2. Predicted development of bertha armyworm (Mamestra configurata) populations near Winnipeg, Manitoba as of June 6, 2021 (projected to June 30, 2021).
Figure 3. Predicted development of bertha armyworm (Mamestra configurata) populations near Lacombe, Alberta as of June 6, 2021 (projected to June 30, 2021).

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” which is a free downloadable document as both an English-enhanced or French-enhanced version.

BERTHA ARMYWORM: THESE HUNGRY CATERPILLARS ARE A MAJOR CANOLA PEST

bertha armyworm (AAFC)

This week’s Insect of the Week is the bertha armyworm (Mamestra configurata), a crop pest with the potential to do serious damage when populations run high. Though these insects are harmless to crops as adults, bertha armyworm larvae primarily consume canola, mustard, and alfalfa. Larvae may also consume plants like flax, peas and potatoes. The bertha armyworm is prevalent across the Prairies.

Prior to reaching their mature larval size, bertha armyworms feed on the underside of leaves. In canola and other plants that drop their leaves prior to the bertha armyworms’ larval maturation, the growing larvae move on to eat seed pods, stripping the pods and in extreme cases, consuming the seeds inside them. Even when the seed pods are not eaten through, stripped pods risk shattering and can hinder crop development.

bertha armyworm damage to seed pods (AAFC)

Adults are 20 millimeters long moths with a greyish body and 40 mm wingspan. Wing markings on the forewing include prominent white, kidney-shaped markings near the midpoint, and an olive and white irregular marking extending along the wing tip. Mature larvae are 40 mm long black (though sometimes light green or light brown) caterpillars with a light brown head and an orange stripe along each side, with three broken white lines down their backs.

bertha armyworm moth (Alberta Agriculture and Rural Development)

Biological and monitoring information related to the bertha armyworm in field crops can be found on our Monitoring page as well as on provincial Agriculture Ministry pages (Manitoba, Saskatchewanand Alberta). For more information, visit the bertha armyworm page in the Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Management field guide. (en français : Guide d’identification des ravageurs des grandes cultures et des cultures fourragères et de leurs ennemis naturels et mesures de lutte applicables à l’Ouest canadien).

Alert: Bertha armyworm development

Model simulations to May 30, 2021, indicate that BAW pupal development is 45-60 % complete across the prairies (Fig. 1). Recent warm conditions in Alberta and southern Manitoba have resulted in the rapid development of BAW pupae (Fig. 2 C). The weather forecast for this week suggests that above-normal temperatures will occur. This could result in faster development of BAW pupae. BAW traps should be placed in fields when pupal development is approximately 80 %.

Figure 1. Predicted bertha armyworm (Mamestra configurata) pupal development across the Canadian prairies as of May 30, 2021.

IMPORTANT: Table 1 provides estimates for when the pheromone-baited green unitrap should be deployed. Based on weather conditions up to May 30, 2021, and model output, BAW adults (Fig. 2 D) may begin to emerge by mid to late June. Typically, moths emerge over an ~6 week period so cumulative counts of moths intercepted in these green unitraps provides insight into anticipated risk and prioritization for in-field scouting of the damaging larval stages later this summer.

Figure 2. The egg stage (A), larval stage (B), pupal stage (C), and adult stage (D) of bertha armyworm.
Photos: Jonathon Williams (AAFC-Saskatoon).

Model projections to June 30 predict that development near Regina (Fig. 3) will be more advanced than at Grande Prairie (Fig. 4). The model predicts that egg hatch will begin in late June near Regina.

Figure 3. Predicted development of bertha armyworm (Mamestra configurata) populations near Regina, Saskatchewan, as of May 30, 2021 (projected to June 30, 2021).
Figure 4. Predicted development of bertha armyworm (Mamestra configurata) populations near Grande Prairie, Alberta as of May 30, 2021 (projected to June 30, 2021).

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also, refer to the bertha armyworm pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” which is a free downloadable document as both an English-enhanced or French-enhanced version.

Bertha armyworm development

Model simulations to May 23, 2021, indicate that overwintered BAW pupal development (Fig. 1, C) varies across the prairies. Development is predicted to be greatest across the southern prairies (Fig. 2). Based on current development, adult emergence is projected to occur in mid-June.

Figure 1. The egg stage (A), larval stage (B), pupal stage (C), and adult stage (D) of bertha armyworm.
Photos: Jonathon Williams (AAFC-Saskatoon).
Figure 2. Predicted bertha armyworm (Mamestra configurata) pupal development across the Canadian prairies as of May 23, 2021.

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of Manitoba, Saskatchewan, Alberta and the Prairie Pest Monitoring Network. Also refer to the bertha armyworm pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” which is a free downloadable document as both an English-enhanced or French-enhanced version.