Predicted alfalfa weevil development

Model simulations for alfalfa weevil (AAW) (Hypera postica) predict, as of June 13, that alfalfa weevil populations should be in the third larval instar (Fig. 1). Fourth instar larvae are predicted to occur across southeastern Saskatchewan and southern Manitoba.

Figure 1. Predicted percent of Hypera postica (alfalfa weevil) population in the third instar stage as of June 13, 2021.

The following graphs indicate that development is more advanced near Brandon (Fig. 2) than Swift Current (Fig. 3). Simulation runs indicate that by June 29, southern Manitoba populations will be in pupal stage whereas Swift Current populations are predicted to be in the fourth instar and pupal stages.

Figure 2. Predicted status of alfalfa weevil (Hypera postica) development for populations near Brandon, Manitoba as of June 13, 2021 (projected to June 29, 2021).
Figure 3. Predicted status of alfalfa weevil (Hypera postica) development for populations near Swift Current, Saskatchewan as of June 13, 2021 (projected to June 29, 2021).

The larval stage of this weevil feeds on alfalfa leaves in a manner that characterizes the pest as a “skeletonizer” (Fig. 4).  The green larva features a dorsal white line down the length of its body, has a dark brown head capsule, and will grow to 9 mm long.  

Figure 4. Developmental stages of the alfalfa weevil (Hypera postica). Composite image: J. Soroka (AAFC-Saskatoon).

Alfalfa growers are encouraged to check the Alfalfa Weevil Fact Sheet prepared by Dr. Julie Soroka (AAFC-Saskatoon).  Additional information can be accessed by reviewing the Alfalfa Weevil Page extracted from the “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide” (2018; accessible in either English-enhanced or French-enhanced versions).

Predicted alfalfa weevil development

Model simulations for alfalfa weevil (AAW) (Hypera postica) predict, as of June 6, that alfalfa weevil populations should be primarily in the second larval instar (Fig. 1). The following graph indicates the predicted development near Brandon (Fig. 2). This week, larval populations in southern Manitoba should be primarily in the second instar. Simulation runs indicate that by June 22, southern Manitoba populations will be in the fourth instar with initial appearance of pupae.

Figure 1. Predicted development of Hypera postica (alfalfa weevil) populations across the prairies as of June 6, 2021.
Figure 2. Predicted status of alfalfa weevil (Hypera postica) development for populations near Brandon, Manitoba as of June 6, 2021 (projected to June 22, 2021).

The larval stage of this weevil feeds on alfalfa leaves in a manner that characterizes the pest as a “skeletonizer” (Fig. 3).  The green larva features a dorsal white line down the length of its body, has a dark brown head capsule, and will grow to 9 mm long.  

Figure 3. Developmental stages of the alfalfa weevil (Hypera postica). Composite image: J. Soroka (AAFC-Saskatoon).

Alfalfa growers are encouraged to check the Alfalfa Weevil Fact Sheet prepared by Dr. Julie Soroka (AAFC-Saskatoon).  Additional information can be accessed by reviewing the Alfalfa Weevil Page extracted from the “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide” (2018; accessible in either English-enhanced or French-enhanced versions).

Predicted alfalfa weevil development

Model simulations for alfalfa weevil (AAW) predict, as of May 30, that egg hatch should be nearly complete across Manitoba and Saskatchewan. First instar larvae should be appearing across most of Manitoba (Fig. 1). The following graphs indicate that development is more advanced near Winnipeg (Fig. 2) than near Lethbridge (Fig. 3). This week, larval populations in southern Manitoba should be primarily in the second instar while populations in southern Alberta may consist of first instar larvae. Results suggest that by June 15, populations will be in the second and third larval instars across southern Alberta and that Manitoba populations will be in third and fourth instar stages.

Figure 1. Predicted development of Hypera postica (alfalfa weevil) populations across the prairies as of May 30, 2021.
Figure 2. Predicted status of alfalfa weevil (Hypera postica) development for populations near Winnipeg, Manitoba as of May 30, 2021 (projected to June 15, 2021).
Figure 3. Predicted status of alfalfa weevil (Hypera postica) development for populations near Lethbridge, Alberta as of May 30, 2021 (projected to June 15, 2021).

The larval stage of this weevil feeds on alfalfa leaves in a manner that characterizes the pest as a “skeletonizer” (Fig. 4).  The green larva features a dorsal white line down the length of its body, has a dark brown head capsule, and will grow to 9 mm long.  

Figure 4. Developmental stages of the alfalfa weevil (Hypera postica). Composite image: J. Soroka (AAFC-Saskatoon).

Alfalfa growers are encouraged to check the Alfalfa Weevil Fact Sheet prepared by Dr. Julie Soroka (AAFC-Saskatoon).  Additional information can be accessed by reviewing the Alfalfa Weevil Page extracted from the “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide” (2018; accessible in either English-enhanced or French-enhanced versions).

Alfalfa weevil predicted development

Model simulations for alfalfa weevil (AAW) predict that oviposition should be well underway across the prairies. The following graphs indicate that development is similar near Swift Current SK (Fig. 1) and Brandon MB (Fig. 2). The model predicts that that hatch may occur during the last week of May and that second instar larvae could be present during the first week of June.

Figure 1. Projected predicted status of alfalfa weevil (Hypera postica) populations near
Swift Current SK as of May 23, 2021 (projected to June 7, 2021).
Figure 2. Projected predicted status of alfalfa weevil (Hypera postica) populations near
Brandon MB as of May 23, 2021 (projected to June 7, 2021).

The larval stage of this weevil feeds on alfalfa leaves in a manner that characterizes the pest as a “skeletonizer” (Fig. 3).  The green larva featuring a dorsal, white line down the length of its body has a dark brown head capsule and will grow to 9 mm long.  

Figure 3. Developmental stages of the alfalfa weevil (Hypera postica). Composite image: J. Soroka (AAFC-Saskatoon).

Alfalfa growers are encouraged to check the Alfalfa Weevil Fact Sheet prepared by Dr. Julie Soroka (AAFC-Saskatoon).  Additional information can be accessed by reviewing the Alfalfa Weevil Page extracted from the “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide” (2018; accessible in either English-enhanced or French-enhanced versions).

Alfalfa weevil predicted development

Model simulations for alfalfa weevil (AAW) predict that oviposition should be well underway across the prairies. The following graphs indicate that development is similar near Swift Current (Fig. 1) and Brandon (Fig. 2). The model predicts that that hatch may occur during the last week of May.

Figure 1. Projected predicted status of alfalfa weevil populations near Swift Current SK as of May 16, 2021 (projected to May 31, 2021).
Figure 2. Projected predicted status of alfalfa weevil populations near Brandon MB as of May 16, 2021 (projected to May 31, 2021).

Alfalfa growers are encouraged to check the Alfalfa Weevil Fact Sheet prepared by Dr. Julie Soroka (AAFC-Saskatoon).  Additional information can be accessed by reviewing the Alfalfa Weevil Page extracted from the “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide” (2018; accessible in either English-enhanced or French-enhanced versions).

Alfalfa weevil predicted development

Model simulations for alfalfa weevil (AAW) indicate that oviposition should be well underway across the prairies. The following graphs indicate, based on potential number of eggs, that development is more advanced near Lethbridge (Fig. 1) than Brandon (Fig. 2). The model predicts that hatch may occur during the last week of May.

Figure 1. Projected predicted status of alfalfa weevil populations near Lethbridge AB as of May 9, 2021.
Figure 2. Projected predicted status of alfalfa weevil populations near Brandon MB as of May 9, 2021.

Alfalfa growers are encouraged to check the Alfalfa Weevil Fact Sheet prepared by Dr. Julie Soroka (AAFC-Saskatoon).  Additional information can be accessed by reviewing the Alfalfa Weevil Page extracted from the “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide” (2018; accessible in either English-enhanced or French-enhanced versions).

Alfalfa weevil predicted development

Models predicting the development of Alfalfa weevil (AAW) across the prairies are updated weekly to help growers time their in-field scouting for second-instar larvae. 

Model simulations for alfalfa weevil (AAW) indicate that oviposition should have begun across central and western areas of the prairies. The following graphs indicate, based on potential number of eggs, that development is more advanced near Regina SK (Fig. 1) than Winnipeg MB (Fig. 2).

Figure 1. Projected predicted status of alfalfa weevil populations near Regina SK as of May 2, 2021.
Figure 2. Projected predicted status of alfalfa weevil populations near Winnipeg MB as of May 2, 2021.

The larval stage of this weevil feeds on alfalfa leaves in a manner that characterizes the pest as a “skeletonizer”.  The green larva featuring a dorsal, white line down the length of its body has a dark brown head capsule and will grow to 9 mm long.  

Figure 3. Developmental stages of the alfalfa weevil (Hypera postica). Composite image: J. Soroka (AAFC-Saskatoon).

Alfalfa growers are encouraged to check the Alfalfa Weevil Fact Sheet prepared by Dr. Julie Soroka (AAFC-Saskatoon).  Additional information can be accessed by reviewing the Alfalfa Weevil Page extracted from the “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide” (2018; accessible in either English-enhanced or French-enhanced versions).