Diamondback moth

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season.

The week of May 27, 2024, very mature larvae were retrieved in flixweed in southern Alberta (Barkley, pers. comm. 2024). Thus, a second generation of adult diamondback moth is likely active in southern parts of the prairies.

Pheromone-baited Delta traps housing sticky cards are used to monitor diamondback moth across the Canadian prairies. Research has shown that cumulative counts > 25 moths indicate elevated risk. In those areas, it then becomes important to scout and assess larval densities.

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.

Scouting and pest management for diamondback moth depends on in-field counts of larvae per metre2! This means plants need to be pulled and tapped off to assess the number of larvae! Use Figure 1 below to help identify the different stages of diamondback moth.

Figure 1. The life stages of the diamondback moth (Plutella xylostella), which can have multiple generations per year. Photos: AAFC-Saskatoon-J. Williams.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba AgricultureSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (2018) accessible a

Diamondback moth

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season.

The week of May 27, 2024, very mature larvae were retrieved in flixweed in southern Alberta (Barkley, pers.comm. 2024). Thus, a second generation of adult diamondback moth is likely active in southern parts of the prairies.

Pheromone-baited Delta traps housing sticky cards are used to monitor diamondback moth across the Canadian prairies. Research has shown that cumulative counts > 25 moths indicate elevated risk. In those areas, it then becomes important to scout and assess larval densities.

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.

Provincial entomologist (Barkley, Tansey, Peru, Gavloski) have kindly provided the following summary for this week:
• Alberta – two traps have caught > 25 adult diamondback moths; one trap deployed in the County of Warner (as of June 15, 2024) and one trap deployed in the County of Grande Prairie (as of June 8, 2024).
• Saskatchewan – 6 RMs have observed cumulative counts >25 (as of June 6, 2024); traps are located near Regina (RM 129), Macroie (RM 285), Buchanan (RM 304), Laura (RM 315), Delisle (RM 345) and Makwa (RM 428). As of June 6, 2024, the highest cumulative count was 61 moths.
• Manitoba – pheromone traps at 20 locations have captured > 25 moths, with cumulative trap catches ranging form 28 to 187. All of the traps with elevated risk are located in the Central, Eastern, South Interlake and North Interlake regions of Manitoba.  

Scouting and pest management for diamondback moth depends on in-field counts of larvae per metre2! This means plants need to be pulled and tapped off to assess the number of larvae! Use Figure 1 below to help identify the different stages of diamondback moth.

Figure 1. The life stages of the diamondback moth (Plutella xylostella), which can have multiple generations per year. Photos: AAFC-Saskatoon-J. Williams.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba AgricultureSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth 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.

Diamondback moth

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season.

Last week, Shelley Barkley (Alberta Agriculture and Irrigation) swept a flixweed patch in a ditch and found very mature diamondback moth larvae in southern Alberta. Thus, in some parts of the prairies, the first local generation of diamondback moth is nearing completion.

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

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba AgricultureSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth 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.

Diamondback moth

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season.

Earlier this week, Shelley Barkley (Alberta Agriculture and Irrigation) swept a flixweed patch in a ditch and found diamondback moth larvae (Fig. 1) that were nearly ready to pupate! Thus, in some parts of the prairies, the first local generation of diamondback moth is well underway and nearing completion.

Figure 1. Diamondback larvae collected using a sweep-net in flixweed growing near Dunmore AB on May 27, 24. Photo: S. Barkley (Alberta Agriculture and Irrigation).

It’s a busy week in the field, so we do not have a full update on diamondback moth trap captures to share this week. Please check out the Provincial Reports for the most up-to-date information available from the diamondback moth pheromone monitoring program.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba AgricultureSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth 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.

Diamondback moth

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season.

Figure 1. The life stages of the diamondback moth (Plutella xylostella), which can have multiple generations per year. Photos: AAFC-Saskatoon-J. Williams.

Spring Pheromone Trap Monitoring of Adult Males: Across the Canadian prairies, spring monitoring is initiated to acquire weekly counts of adult moths attracted to pheromone-baited delta traps deployed in fields. Thank you to the many people who deployed and are weekly checking traps across the BC Peace, Alberta, Saskatchewan, and Manitoba! Weekly trap interceptions are observed to generate cumulative counts.

As the season progresses, cumulative count estimates arising from these pheromone traps are broadly categorized to help producers prioritize and time in-field scouting for larvae. Preliminary data from the initial weeks of monitoring includes:

  • Alberta – So far, two traps in southern Alberta have caught more than 10 moths, one in Mountain View County and one in Kneehill County. Visit Alberta Agriculture and Irrigation’s ‘live’ reporting map for updates through the 2024 growing season.
  • Saskatchewan – Dr. James Tansey and Carter Peru (Saskatchewan Ministry of Agriculture) shared that traps near Regina (RM129), Makwa (RM561), and Lumsden (RM189) have caught 20-25 adult diamondback moths. Several traps have also caught more than 25 moths so far this monitoring season, including traps near Laura (RM315), Delisle (RM345), Macroie (RM285), and Buchanan (RM304).
  • Manitoba – Dr. John Gavloski (Manitoba Agriculture) reported that five diamondback moth traps have now captured more than 25 moths in Manitoba. These traps are located in the Central region (2), Eastern region (1) and North Interlake region (2) of the province. So far, the highest cumulative count in a single trap is 69.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba AgricultureSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth 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.

Diamondback moth

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season.

Figure 1. The life stages of the diamondback moth (Plutella xylostella), which can have multiple generations per year. Photos: AAFC-Saskatoon-J. Williams.

Spring Pheromone Trap Monitoring of Adult Males: Across the Canadian prairies, spring monitoring is initiated to acquire weekly counts of adult moths attracted to pheromone-baited delta traps deployed in fields. Thank you to the many people who deployed and are weekly checking traps across the BC Peace, Alberta, Saskatchewan, and Manitoba! Weekly trap interceptions are observed to generate cumulative counts.

As the season progresses, cumulative count estimates arising from these pheromone traps are broadly categorized to help producers prioritize and time in-field scouting for larvae. Preliminary data from the initial weeks of monitoring includes:

  • Alberta – So far, cumulative trap counts ranged from 0-10 moths with the highest interception rates arising from near Barrhead and Camrose AB. Visit Alberta Agriculture and Irrigation’s ‘live’ reporting map for updates through the 2024 growing season.
  • Saskatchewan – Dr. James Tansey and Carter Peru (Saskatchewan Ministry of Agriculture) shared results arising the weeks of May 1 and May 8, 2024; cumulative trap catches so far ranged from 0-16 with traps near Navscoy, Lumsden, and Coteau SK reporting the most so far.
  • Manitoba – Dr. John Gavloski (Manitoba Agriculture) reported that cumulative diamondback moth trap catches ranged from 0-23 for the majority of traps but that two sites reported >25 total moths. One site in the Eastern region has intercepted 33 moths and one trap in the North Interlake region has intercepted 61 moths.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba AgricultureSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth 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.

Wind Trajectory Summaries Unavailable in 2024

In 2024, the PPMN is unable to generate Wind Trajectory summaries.

Historically, the PPMN posted wind trajectory reports through collaboration between Agriculture and Agri-Food Canada and Environment and Climate Change Canada. Trajectories originating over northwestern and southern USA and Mexico – anywhere diamondback moth populations exist year-round and from which adults may actively migrate from were followed, summarized, and reported.

Access background information on how and why wind trajectories are monitored.

Diamondback moth

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season.

Spring Pheromone Trap Monitoring of Adult Males: Across the Canadian prairies, spring monitoring is initiated to acquire weekly counts of adult moths attracted to pheromone-baited delta traps deployed in fields. Thank you to the many people who deployed and are weekly checking traps across the BC Peace, Alberta, Saskatchewan, and Manitoba! Weekly trap interceptions are observed to generate cumulative counts.

As the season progresses, cumulative count estimates arising from these pheromone traps are broadly categorized to help producers prioritize and time in-field scouting for larvae. Preliminary data from the initial week of monitoring includes:

  • Alberta – So far, Shelley Barkley (Alberta Agriculture and Irrigation) reported that low numbers of diamondback moth were captured at a few monitoring locations in southern and eastern Alberta and noted the Alberta Agriculture and Irrigation’s ‘live’ reporting map is active for 2024.
  • Saskatchewan – Dr. James Tansey (Saskatchewan Ministry of Agriculture) also reported that adult diamondback moth were captured at a few locations in Saskatchewan.
  • Manitoba – Dr. John Gavloski (Manitoba Agriculture) reported that diamondback moth were observed from 13 traps; 3 traps intercepted 10 or above, but no larger counts yet.
Figure 1. The life stages of the diamondback moth (Plutella xylostella), which can have multiple generations per year. Photos: AAFC-Saskatoon-J. Williams.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba AgricultureSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth 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 diamondback moth development

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season.

Recent warm conditions have resulted in the rapid development of diamondback moth populations. Model simulations to August 14, 2022, indicate that the fourth generation of non-migrant adults (based on mid-May arrival dates) are currently occurring across the southern prairies (Fig. 1). DBM development is predicted to be marginally greater in 2022 than expected based on long-term average values (Fig. 2).

Warm conditions during August resulted in rapid development of diamondback moth populations. Model simulations to August 21, 2022, indicate that the fourth generation of non-migrant adults (based on mid-May arrival dates) are currently occurring across most of the prairies (Fig. 1). DBM development is predicted to be marginally greater than long-term average values (Fig. 2).

Figure 1. Predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of August 21, 2022.
Figure 2. Long-term predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of August 21, based on climate normal data.

In-Field Monitoring: Remove plants in an area measuring 0.1 m² (about 12″ square), beat them onto a clean surface and count the number of larvae (Fig. 3) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Figure 3. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.

The economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

This image has an empty alt attribute; its file name is DBM_Pupa_AAFC-1.jpg
Figure 4. Diamondback moth pupa within silken cocoon.
This image has an empty alt attribute; its file name is DBM_adult_AAFC-1.png
Figure 5. Adult diamondback moth.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba Agriculture and Resource DevelopmentSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth 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.

Diamondback moth was the Insect of the Week for Wk10 in 2021!

Predicted diamondback moth development

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season.

Recent warm conditions have resulted in the rapid development of diamondback moth populations. Model simulations to August 14, 2022, indicate that the fourth generation of non-migrant adults (based on mid-May arrival dates) are currently occurring across the southern prairies (Fig. 1). DBM development is predicted to be marginally greater in 2022 than expected based on long-term average values (Fig. 2).

Figure 1. Predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of August 14, 2022.
Figure 2. Long-term predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of August 14, based on climate normal data.

In-Field Monitoring: Remove plants in an area measuring 0.1 m² (about 12″ square), beat them onto a clean surface and count the number of larvae (Fig. 2) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Figure 3. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.

The economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

This image has an empty alt attribute; its file name is DBM_Pupa_AAFC-1.jpg
Figure 4. Diamondback moth pupa within silken cocoon.
This image has an empty alt attribute; its file name is DBM_adult_AAFC-1.png
Figure 5. Adult diamondback moth.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba Agriculture and Resource DevelopmentSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth 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.

Diamondback moth was the Insect of the Week for Wk10 in 2021!

Predicted diamondback moth development

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season.

Model simulations to August 7, 2022, indicate that the third generation of non-migrant adults (based on mid-May arrival dates) are currently occurring across most of the prairies (Fig. 1). DBM development is predicted to be marginally greater in 2022 than expected based on long-term average values (Fig. 2).

Figure 1. Predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of August 7, 2022.
Figure 2. Long-term predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of August 7, based on climate normal data.

Spring Pheromone Trap Monitoring of Adult Males: Across the Canadian prairies, spring monitoring is initiated to acquire weekly counts of adult moths attracted to pheromone-baited delta traps deployed in fields. Weekly trap interceptions are observed to generate cumulative counts. Summaries or maps of cumulative DBM data are available for Manitoba, Saskatchewan and Alberta. These cumulative count estimates are broadly categorized to help producers prioritize and time in-field scouting for larvae.

In-Field Monitoring: Remove plants in an area measuring 0.1 m² (about 12″ square), beat them onto a clean surface and count the number of larvae (Fig. 2) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Figure 3. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.

The economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

This image has an empty alt attribute; its file name is DBM_Pupa_AAFC-1.jpg
Figure 4. Diamondback moth pupa within silken cocoon.
This image has an empty alt attribute; its file name is DBM_adult_AAFC-1.png
Figure 5. Adult diamondback moth.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba Agriculture and Resource DevelopmentSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth 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.

Diamondback moth was the Insect of the Week for Wk10 in 2021!

Predicted diamondback moth development

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season.

Model simulations to July 31, 2022, indicate that the third generation of non-migrant adults (based on mid-May arrival dates) is currently occurring across the southern prairies (Fig. 1). DBM development is predicted to be marginally greater this year than expected based on long-term average values (Fig. 2).

Figure 1. Predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of July 31, 2022.
Figure 2. Long-term predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of July 31, based on climate normal data.

In-Field Monitoring: Remove plants in an area measuring 0.1 m² (about 12″ square), beat them onto a clean surface and count the number of larvae (Fig. 3) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Figure 3. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.

The economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

This image has an empty alt attribute; its file name is DBM_Pupa_AAFC-1.jpg
Figure 4. Diamondback moth pupa within silken cocoon.
This image has an empty alt attribute; its file name is DBM_adult_AAFC-1.png
Figure 5. Diamondback moth.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba Agriculture and Resource DevelopmentSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth 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.

Diamondback moth was the Insect of the Week for Wk10 in 2021!

Predicted diamondback moth development

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season.

Model simulations to July 24, 2022, indicate that the third generation of non-migrant adults (based on mid-May arrival dates) are currently occurring across the southern prairies (Fig. 1). DBM development is predicted to be marginally greater than long-term average values (Fig. 2).

Figure 1. Predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of July 24, 2022.
Figure 2. Long-term predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of July 24, based on climate normal data.

Spring Pheromone Trap Monitoring of Adult Males: Across the Canadian prairies, spring monitoring is initiated to acquire weekly counts of adult moths attracted to pheromone-baited delta traps deployed in fields. Weekly trap interceptions are observed to generate cumulative counts. Summaries or maps of cumulative DBM data are available for Manitoba, Saskatchewan and Alberta. These cumulative count estimates are broadly categorized to help producers prioritize and time in-field scouting for larvae.

In-Field Monitoring: Remove plants in an area measuring 0.1 m² (about 12″ square), beat them onto a clean surface and count the number of larvae (Fig. 2) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Figure 2. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.

The economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

This image has an empty alt attribute; its file name is DBM_Pupa_AAFC-1.jpg
Figure 3. Diamondback moth pupa within silken cocoon.
This image has an empty alt attribute; its file name is DBM_adult_AAFC-1.png
Figure 4. Diamondback moth.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba Agriculture and Resource DevelopmentSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth 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.

Diamondback moth was the Insect of the Week for Wk10 in 2021!

Predicted diamondback moth development

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season.

Model simulations to July 17, 2022, indicate that the second generation of non-migrant adults (based on mid-May arrival dates) are currently occurring across the Canadian prairies (Fig. 1). This week, development of the second generation has expanded across most of the Peace River region and the third generation is predicted to occur in a localized region of southern Manitoba. DBM development is predicted to be similar to average values (Fig. 2).

Figure 1. Predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of July 17, 2022.
Figure 2. Long-term predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of July 17, based on climate normal data.

Spring Pheromone Trap Monitoring of Adult Males: Across the Canadian prairies, spring monitoring is initiated to acquire weekly counts of adult moths attracted to pheromone-baited delta traps deployed in fields. Weekly trap interceptions are observed to generate cumulative counts. Summaries or maps of cumulative DBM data are available for Manitoba, Saskatchewan and Alberta. These cumulative count estimates are broadly categorized to help producers prioritize and time in-field scouting for larvae.

In-Field Monitoring: Remove plants in an area measuring 0.1 m² (about 12″ square), beat them onto a clean surface and count the number of larvae (Fig. 2) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Figure 2. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.

The economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

This image has an empty alt attribute; its file name is DBM_Pupa_AAFC-1.jpg
Figure 3. Diamondback moth pupa within silken cocoon.
This image has an empty alt attribute; its file name is DBM_adult_AAFC-1.png
Figure 4. Diamondback moth.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba Agriculture and Resource DevelopmentSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth 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.

Diamondback moth was the Insect of the Week for Wk10 in 2021!

Predicted diamondback moth development

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season.

Model simulations to July 10, 2022, indicate the second generation of non-migrant adults (based on mid-May arrival dates) are currently occurring across the Canadian prairies (Fig. 1). DBM development is predicted to be similar to long-term average development for this time of the growing season (Fig. 2).

Figure 1. Predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of July 10, 2022.
Figure 2. Long-term predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of July 10, based on climate normal data.

Spring Pheromone Trap Monitoring of Adult Males: Across the Canadian prairies, spring monitoring is initiated to acquire weekly counts of adult moths attracted to pheromone-baited delta traps deployed in fields. Weekly trap interceptions are observed to generate cumulative counts. Summaries or maps of cumulative DBM data are available for Manitoba, Saskatchewan and Alberta. These cumulative count estimates are broadly categorized to help producers prioritize and time in-field scouting for larvae.

In-Field Monitoring: Remove plants in an area measuring 0.1 m² (about 12″ square), beat them onto a clean surface and count the number of larvae (Fig. 2) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Figure 2. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.

The economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

This image has an empty alt attribute; its file name is DBM_Pupa_AAFC-1.jpg
Figure 3. Diamondback moth pupa within silken cocoon.
This image has an empty alt attribute; its file name is DBM_adult_AAFC-1.png
Figure 4. Diamondback moth.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba Agriculture and Resource DevelopmentSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth 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.

Diamondback moth was the Insect of the Week for Wk10 in 2021!

Predicted diamondback moth development

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season.

Recent warm conditions should result in the development of DBM populations. Model simulations to July 3, 2022, indicate that the first generation of non-migrant adults (based on mid-May arrival dates) are currently occurring across the Canadian prairies and that the second generation is emerging across Manitoba and Saskatchewan (Fig. 1). DBM development is predicted to be similar to average values (Fig. 2).

Figure 1. Predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of July 3, 2022.
Figure 2. Long-term predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of July 3, based on climate normal data.

Spring Pheromone Trap Monitoring of Adult Males: Across the Canadian prairies, spring monitoring is initiated to acquire weekly counts of adult moths attracted to pheromone-baited delta traps deployed in fields. Weekly trap interceptions are observed to generate cumulative counts. Summaries or maps of cumulative DBM data are available for Manitoba, Saskatchewan and Alberta. These cumulative count estimates are broadly categorized to help producers prioritize and time in-field scouting for larvae.

In-Field Monitoring: Remove plants in an area measuring 0.1 m² (about 12″ square), beat them onto a clean surface and count the number of larvae (Fig. 2) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Figure 2. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.

The economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

This image has an empty alt attribute; its file name is DBM_Pupa_AAFC-1.jpg
Figure 3. Diamondback moth pupa within silken cocoon.
This image has an empty alt attribute; its file name is DBM_adult_AAFC-1.png
Figure 4. Diamondback moth.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba Agriculture and Resource DevelopmentSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth 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.

Diamondback moth was the Insect of the Week for Wk10 in 2021!

Predicted diamondback moth development

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season.

Model simulations to June 26, 2022, indicate that the first generation of non-migrant adults (based on mid May arrival dates) are currently occurring across the Canadian prairies and that the start of the second generation is emerging in southern Manitoba (Fig. 1).

Figure 1. Predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of June 26, 2022.

Spring Pheromone Trap Monitoring of Adult Males: Across the Canadian prairies, spring monitoring is initiated to acquire weekly counts of adult moths attracted to pheromone-baited delta traps deployed in fields. Weekly trap interceptions are observed to generate cumulative counts. Summaries or maps of cumulative DBM data are available for Manitoba, Saskatchewan and Alberta. These cumulative count estimates are broadly categorized to help producers prioritize and time in-field scouting for larvae.

In-Field Monitoring: Remove plants in an area measuring 0.1 m² (about 12″ square), beat them onto a clean surface and count the number of larvae (Fig. 2) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Figure 2. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.

The economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

This image has an empty alt attribute; its file name is DBM_Pupa_AAFC-1.jpg
Figure 3. Diamondback moth pupa within silken cocoon.
This image has an empty alt attribute; its file name is DBM_adult_AAFC-1.png
Figure 4. Diamondback moth.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba Agriculture and Resource DevelopmentSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth 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.

Diamondback moth was the Insect of the Week for Wk10 in 2021!

Weekly Wind Trajectory Report for May 30

Access background information on how and why wind trajectories are monitored. Reverse and forward trajectories are available in this report.

1. REVERSE TRAJECTORIES (RT)
Since May 1, 2022, the majority of reverse trajectories crossing the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1). Relative to previous weeks, this past week (May 24-30, 2022) there was a significant increase in the number of trajectories (PNW, OK/TX and NE/KS) that passed over the prairies.

Figure 1. Average number (based on a 5-day running average) of reverse trajectories (RT) crossing the prairies for the period of May 1-30, 2022.

a. Pacific Northwest (Idaho, Oregon, Washington) – The majority of Pacific Northwest reverse trajectories have been reported to pass over southern and central Alberta and western Saskatchewan (Fig. 2).

Figure 2. Total number of dates with reverse trajectories originating over the Idaho, Oregon, and Washington that have crossed the prairies between April 1 and May 30, 2022.

b. Mexico and southwest USA (Texas, California) – This past week there have not been any reverse trajectories that originated from Mexico, California or Texas. Since April 1, reverse trajectories were reported for Manitoba (Portage, Selkirk, Brandon, Carman, Russell) and eastern Saskatchewan (Gainsborough, Grenfell) (Fig. 3).

Figure 3. The total number of dates with reverse trajectories originating over Mexico, California and Texas that have crossed the prairies between April 1 and May 30, 2022.

c. Oklahoma and Texas – Since April 1, reverse trajectories were reported for Manitoba and eastern Saskatchewan (Fig. 4). This past week (May 24-30, 2022) there was an increase in the number of reverse trajectories that have crossed over southeastern Saskatchewan (Weyburn and Gainsborough) and Manitoba (Portage and Brandon) relative to previous weeks.

Figure 4. The total number of dates with reverse trajectories originating over Texas and Oklahoma that have crossed the prairies between May 1 and May 30, 2022.

d. Nebraska and Kansas – Reverse trajectories, originating from Kansas and Nebraska have crossed southeastern Saskatchewan and southern Manitoba (April 1 – May 23, 2022) (Fig. 5). This past week (May 24-30, 2022) there was an increase in the number of reverse trajectories that have crossed over eastern Saskatchewan and Manitoba relative to previous weeks.

Figure 5. The total number of dates with reverse trajectories originating over Kansas and Nebraska that have crossed the prairies between April 1 and May 30, 2022.

2. FORWARD TRAJECTORIES (FT)
The following map presents the total number of dates (since April 1, 2022) with forward trajectories (originating from Mexico and USA) that were predicted to cross the Canadian prairies (Fig. 6). Results indicate that the greatest number of forward trajectories entering the prairies have originated from the Pacific Northwest (Idaho, Oregon, Washington), Montana and Wyoming.

Figure 6. Total number of dates with forward trajectories, originating from various regions of the United States and Mexico, crossing the prairies between April 1 and May 30, 2022.

View historical PPMN wind trajectory reports by following this link which sorts the reports from most recent to oldest.

Weekly Wind Trajectory Report for May 23

Access background information on how and why wind trajectories are monitored. Reverse and forward trajectories are available in this report.

1. REVERSE TRAJECTORIES (RT)
Since May 1, 2022, the majority of reverse trajectories that have crossed the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1). Relative to previous weeks, this past week (May 17-23, 2022) there were fewer trajectories passing over the prairies.

Figure 1. Average number (based on a 5-day running average) of reverse trajectories (RT) crossing the prairies for the period of May 1-23, 2022.

a. Pacific Northwest (Idaho, Oregon, Washington) – The majority of Pacific Northwest reverse trajectories have been reported to pass over southern and central Alberta and western Saskatchewan (Fig. 2).

Figure 2. Total number of dates with reverse trajectories originating over the Idaho, Oregon, and Washington that have crossed the prairies between April 1 and May 23, 2022.

b. Mexico and southwest USA (Texas, California) – This past week there were no reverse trajectories originating from Mexico, California or Texas. Since April 1, reverse trajectories were reported for Manitoba (Portage, Selkirk, Brandon, Carman, Russell) and eastern Saskatchewan (Gainsborough, Grenfell) (Fig. 3).

Figure 3. The total number of dates with reverse trajectories originating over Mexico, California and Texas that have crossed the prairies between April 1 and May 23, 2022.

c. Oklahoma and Texas – Since April 1, reverse trajectories were reported for Manitoba and eastern Saskatchewan (Fig. 4). No trajectories were predicted for May 17-23, 2022.

Figure 4. The total number of dates with reverse trajectories originating over Texas and Oklahoma that have crossed the prairies between May 1 and May 23, 2022.

d. Nebraska and Kansas – Reverse trajectories, originating from Kansas and Nebraska have crossed southeastern Saskatchewan and southern Manitoba (April 1 – May 23, 2022) (Fig. 5).

Figure 5. The total number of dates with reverse trajectories originating over Kansas and Nebraska that have crossed the prairies between April 1 and May 23, 2022.

2. FORWARD TRAJECTORIES (FT)
The following map presents the total number of dates (since April 1, 2022) with forward trajectories (originating from Mexico and USA) predicted to cross the Canadian prairies (Fig. 6). Results indicate that the greatest number of forward trajectories entering the prairies have originated from the Pacific Northwest (Idaho, Oregon, Washington), Montana and Wyoming.

Figure 6. Total number of dates with forward trajectories, originating from various regions of the United States and Mexico, crossing the prairies between April 1 and May 23, 2022.

Weekly Wind Trajectory Report for May 16

Access background information on how and why wind trajectories are monitored. Reverse and forward trajectories are available in this report.

1. REVERSE TRAJECTORIES (RT)
Since May 1, 2022, the majority of reverse trajectories crossing the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1).

Figure 1. Average number (based on a 5-day running average) of reverse trajectories (RT) crossing the prairies for the period of May 1-16, 2022.

a. Pacific Northwest (Idaho, Oregon, Washington) – The majority of Pacific Northwest reverse trajectories have passed over south-central Alberta and western Saskatchewan (link to view Fig. 2).

b. Mexico and southwest USA (Texas, California)Since April 1, reverse trajectories were reported for Manitoba (Portage, Selkirk, Brandon, Carman, Russell) and eastern Saskatchewan (Gainsborough, Grenfell) (link to view Fig. 3).

c. Oklahoma and Texas – Since April 1, reverse trajectories were reported for Manitoba and eastern Saskatchewan (link to view Fig. 4).

2. FORWARD TRAJECTORIES (FT)
The following map presents the total number of dates (since April 1, 2022) with forward trajectories (originating from Mexico and USA) predicted to cross the Canadian prairies (Fig. 5). Results indicate that the greatest number of forward trajectories entering Canada originated from the Pacific Northwest (Idaho, Oregon, Washington).

Figure 5. Total number of dates with forward trajectories, originating from various regions of the United States and Mexico, crossing the prairies between April 1 and May 16, 2022.

Predicted diamondback moth development

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Model runs based on climate normals data indicate that most DBM populations should be in the third generation with second-generation DBM predicted for areas within the Peace River region and localized areas of fourth-generation DBM occurring across southern Alberta, Saskatchewan and Manitoba (Fig. 1). Model simulations based on current growing season weather indicate that, compared to climate normal results, there has been an additional generation (fourth) of non-migrant adults that are currently occurring across the Canadian prairies (Fig. 2).

Figure 1. Predicted number of non-migrant generations of diamondback moth (Plutella xylostella) that are expected to have occurred across the Canadian prairies as of August 15 (based on climate normals data).
Figure 2. Predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to occur across the Canadian prairies as of August 15, 2021.

Monitoring: Remove plants in an area measuring 0.1 m² (about 12″ square), beat them onto a clean surface and count the number of larvae (Fig. 3) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Figure 3. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.

The economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

This image has an empty alt attribute; its file name is DBM_Pupa_AAFC-1.jpg
Figure 4. Diamondback moth pupa within silken cocoon.
This image has an empty alt attribute; its file name is DBM_adult_AAFC-1.png
Figure 5. Diamondback moth.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba Agriculture and Resource DevelopmentSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth 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 diamondback moth development

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. The model, based on climate data, indicates most DBM populations should be in the third generation (Fig. 1). Model simulations to August 8, 2021, predict an additional generation for the current growing season PLUS a third and fourth generation of non-migrant adults are currently emerging across the Canadian prairies (Fig. 2).

Figure 1. Predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to occur across the Canadian prairies as of August 8 (based on climate normals data).
Figure 2. Predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to occur across the Canadian prairies as of August 8, 2021.

Monitoring: Remove plants in an area measuring 0.1 m² (about 12″ square), beat them onto a clean surface and count the number of larvae (Fig. 3) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Figure 3. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.

The economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

This image has an empty alt attribute; its file name is DBM_Pupa_AAFC-1.jpg
Figure 4. Diamondback moth pupa within silken cocoon.
This image has an empty alt attribute; its file name is DBM_adult_AAFC-1.png
Figure 5. Diamondback moth.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba Agriculture and Resource DevelopmentSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth 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 diamondback moth development

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season.

Model simulations to August 1, 2021, indicate that the third and fourth generation of non-migrant adults are currently emerging across the Canadian prairies (Fig. 1). Compared to long-term average data (climate normal) sufficient heat units have accumulated to produce a predicted an additional generation for the current growing season (Fig. 2).

Figure 1. Predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to occur across the Canadian prairies as of August 1, 2021.
Figure 2. Long-term average predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to occur across the Canadian prairies as of August 1 (based on climate normals data).

Monitoring: Remove plants in an area measuring 0.1 m² (about 12″ square), beat them onto a clean surface and count the number of larvae (Fig. 3) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Figure 3. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.

The economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

This image has an empty alt attribute; its file name is DBM_Pupa_AAFC-1.jpg
Figure 4. Diamondback moth pupa within silken cocoon.
This image has an empty alt attribute; its file name is DBM_adult_AAFC-1.png
Figure 5. Diamondback moth.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba Agriculture and Resource DevelopmentSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth 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 diamondback moth development

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season. Diamondback moth was the Insect of the Week for Wk10!

Model simulations to July 11, 2021, indicate that the second generation of non-migrant adults are currently emerging across the Canadian prairies (Fig. 1). A third generation is predicted for southern Manitoba. Based on climate normal inputs, development is well ahead of long-term average values (Figure 2). Based on current weather, the mean number of generations that have occurred is 2.1 compared to model runs, based on climate normals, predict that the number of generations should be 1.4.

Figure 1. Predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of July 11, 2021.
Figure 2. Long-term average predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of July 13 (based on climate normals data).

Monitoring: Remove plants in an area measuring 0.1 m² (about 12″ square), beat them onto a clean surface and count the number of larvae (Fig. 2) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Figure 2. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.

The economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

This image has an empty alt attribute; its file name is DBM_Pupa_AAFC-1.jpg
Figure 3. Diamondback moth pupa within silken cocoon.
This image has an empty alt attribute; its file name is DBM_adult_AAFC-1.png
Figure 4. Diamondback moth.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba Agriculture and Resource DevelopmentSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth 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 diamondback moth development

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season. Diamondback moth is the Insect of the Week for Wk10!

Model simulations to July 4, 2021, indicate that the second generation of non-migrant adults are currently emerging across the Canadian prairies (Fig. 1). Across the prairies, development, as of July 4, 2021, is well ahead of long-term average values (Fig. 2).

Figure 1. Predicted number of non-migrant generations of diamondback moth (Plutella xylostella) that are expected to have occurred across the Canadian prairies as of July 4, 2021.
Figure 2. Long-term average predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of July 4 (based on climate normals data).

Monitoring: Remove plants in an area measuring 0.1 m² (about 12″ square), beat them onto a clean surface and count the number of larvae (Fig. 2) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Figure 2. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.

The economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

This image has an empty alt attribute; its file name is DBM_Pupa_AAFC-1.jpg
Figure 3. Diamondback moth pupa within silken cocoon.
This image has an empty alt attribute; its file name is DBM_adult_AAFC-1.png
Figure 4. Diamondback moth.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba Agriculture and Resource DevelopmentSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth 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).

Weekly Wind Trajectory Report for June 28

Access background information for how and why wind trajectories are monitored in this post.

1. REVERSE TRAJECTORIES (RT)
Since June 16, 2021, a decreasing number of reverse trajectories have moved north from the Pacific Northwest (Idaho, Oregon and Washington), Texas, Oklahoma, Kansas and Nebraska (Fig. 1). Though these US regions can be a source of diamondback moths (DBM), the ECCC models predict air movement, not actual occurrence of diamondback moths. Fields (and DBM traps) should be monitored for DBM adults and larvae.

Figure 1. The average number (based on a 5 day running average) of reverse trajectories that have crossed the prairies for the period of May 28 – June 28, 2021.

a. Pacific Northwest (Idaho, Oregon, Washington) – This week (June 22-28, 2021) there were 3 trajectories that crossed Alberta, Manitoba and Saskatchewan that originated in the Pacific Northwest.

b. Mexico and southwest USA (Texas, California) – This week (June 22-28, 2021) there were 0 trajectories that originated in Mexico or the southwest USA that crossed the prairies.

c. Oklahoma and Texas – This week (June 22-28, 2021) there were 0 trajectories originating in Oklahoma or Texas that passed over the prairies.

d. Kansas and Nebraska – This week (June 22-28, 2021) there were 0 trajectories that originated in Kansas or Nebraska that passed over the prairies.

2. FORWARD TRAJECTORIES (FT)
a. Since June 9, 2021 there has been a steady decrease in the number of forward trajectories that are predicted to cross the prairies (Fig. 2). The dates on the graph report when the trajectories originated in the USA (blue bars). These trajectories generally require 3-5 days to enter the prairies (red line).

Figure 2. The average number (based on a 5 day running average) of forward trajectories that were predicted to cross the prairies for the period of May 28-June 28, 2021.

Predicted diamondback moth development

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season.

Model simulations to June 27, 2021, indicate that the first generation of non-migrant adults are currently emerging across the Canadian prairies and that the start of the second generation is occurring in southern Manitoba and southeastern Saskatchewan (Figure 1).

Figure 1. Predicted number of non-migrant generations of diamondback moth (Plutella xylostella) that are expected to have occurred across the Canadian prairies as of June 27, 2021.

Monitoring: Remove plants in an area measuring 0.1 m² (about 12″ square), beat them onto a clean surface and count the number of larvae (Fig. 2) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Figure 2. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.

The economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

This image has an empty alt attribute; its file name is DBM_Pupa_AAFC-1.jpg
Figure 3. Diamondback moth pupa within silken cocoon.
This image has an empty alt attribute; its file name is DBM_adult_AAFC-1.png
Figure 4. Diamondback moth.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba Agriculture and Resource DevelopmentSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth 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 diamondback moth development

Diamondback moths (DBM) (Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season.

Model simulations to June 20, 2021, indicate that the first generation of non-migrant adults are currently emerging across the Canadian prairies and that the start of the second generation is occurring in southern Manitoba (Fig. 1).

Figure 1 Predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of June 20, 2021.

So far, Manitoba, Saskatchewan, Alberta and the BC Peace are all reporting relatively low numbers of intercepted DBM in pheromone traps (read provincial insect pest report links) despite the fact that favourable wind trajectories have passed over the Canadian prairies from southern regions of North America (review wind trajectory reports for 2021). Even so, once DBM are present in an area, it is important to monitor individual canola fields for larvaeWarm growing conditions can quickly translate into multiple generations in a very short time so use the following photos to help identify larvae (Fig. 2), pupae (Fig. 3), or adults (Fig. 4)!

Monitoring: Remove plants in an area measuring 0.1 m² (about 12″ square), beat them onto a clean surface and count the number of larvae (Fig. 2) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Figure 2. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.

The economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1 m² (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

This image has an empty alt attribute; its file name is DBM_Pupa_AAFC-1.jpg
Figure 3. Diamondback moth pupa within silken cocoon.
This image has an empty alt attribute; its file name is DBM_adult_AAFC-1.png
Figure 4. Diamondback moth.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba Agriculture and Resource DevelopmentSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth 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 diamondback moth development

Diamondback moths (DBM; Plutella xylostella) are a migratory invasive species. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce and this results in subsequent non-migrant populations that may have three or four generations during the growing season. Model simulations to June 13, 2021 (using a biofix date of May 15, 2021), indicate that the first generation of non-migrant adults are currently emerging across the Canadian prairies (Fig. 1).

Fig. 1 Predicted number of non-migrant generations of diamondback moth (Plutella xylostella) expected to have occurred across the Canadian prairies as of June 13, 2021.

So far, Manitoba, Saskatchewan, Alberta and the BC Peace are all reporting relatively low numbers of intercepted DBM in pheromone traps (read provincial insect pest report links) despite the fact that favourable wind trajectories have passed over the Canadian prairies from southern regions of North America (review wind trajectory reports for 2021). Even so, once DBM are present in an area, it is important to monitor individual canola fields for larvaeWarm growing conditions can quickly translate into multiple generations in a very short time so use the following photos to help identify larvae (Fig. 2), pupae (Fig. 3), or adults (Fig. 4)!

Monitoring: Remove plants in an area measuring 0.1 m² (about 12″ square), beat them onto a clean surface and count the number of larvae (Fig. 2) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Figure 2. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.

The economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

This image has an empty alt attribute; its file name is DBM_Pupa_AAFC-1.jpg
Figure 3. Diamondback moth pupa within silken cocoon.
This image has an empty alt attribute; its file name is DBM_adult_AAFC-1.png
Figure 4. Diamondback moth.

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba Agriculture and Resource DevelopmentSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  Also, refer to the diamondback moth 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).

Diamondback moth

Once diamondback moth is present in the area, it is important to monitor individual canola fields for larvae.  Warm growing conditions can quickly translate into multiple generations in a very short period!

Wind Trajectory Updates – Completed for 2020 growing season as of Week 09 (released June 22, 2020).

Weekly Pheromone-baited Trapping Results – Early season detection of diamondback moth is improved through the use of pheromone-baited delta traps deployed in fields across the Canadian prairies.  Click each province to access moth reporting numbers observed in AlbertaSaskatchewan and Manitoba as they become available. Check these sites to assess cumulative counts and relative risk in your geographic region.

Monitoring: Remove the plants in an area measuring 0.1 m² (about 12″ square), beat them on to a clean surface and count the number of larvae (Fig. 1) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Figure 1. Diamondback larva measuring ~8 mm long.Note brown head capsule and forked appearance of prolegs on posterior.
Figure 2. Diamondback moth pupa within silken cocoon.

Economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

Figure 3. Diamondback moth.

Biological and monitoring information for DBM is posted by Manitoba AgricultureSaskatchewan Agriculture, and the Prairie Pest Monitoring Network.  

More information about Diamondback moths can be found by accessing the pages from the  “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide“.  View ONLY the Diamondback moth page but remember the guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.