Cutworms

Manitoba continues to experience cutworm issues this spring!  Thanks to John Gavloski (Manitoba Agriculture) who was able to provide a quick summary:

There has been a lot of insecticide applications and some reseeding of crops in Manitoba because of cutworms. Damage is to a variety of crops. Redbacked and dingy cutworms have been the two dominant species, although some other species of cutworms are being found. They are starting to turn to pupae, however stages are quite variable in some fields and scouting and insecticide applications continue.

Please refer back to our earlier Cutworm post (Wk05) for help with scouting and identification tips.  Also access the free downloadable Cutworm Field Guide.

Insect of the Week – Doppelgangers: Bertha armyworm and clover cutworm

The case of the bertha armyworm and the clover cutworm (and other cutworm species)

Clover cutworm larva
cc-by 3.0 Lo Troisfontaine
Bertha armyworm – caterpillar 
Mike Dolinski, MikeDolinski@hotmail.com

Are those bertha armyworms (Mamestra configurata) eating your canola, mustard or alfalfa (also found on lamb’s-quarters, peas, flax, potato)? Or is it maybe a clover cutworm (Discestra trifolii)? [Note: not all cutworm species spend their larval stage underground.] The larvae of the two species are doppelgangers as they are similar in appearance, have a large overlap in host crops, and have similar timing (June-September). Telling them apart can be a challenge but here are few tips to focus on to help distinguish:

Colour:

  • there are generally fewer velvety black clover cutworm caterpillars, with most of the clover cutworm larvae being green or pale brown

Lateral stripe:

  • On the clover cutworm it is yellowish-pink
  • On the bertha armyworm it is yellowish-orange
Climbing cutworm larva – from Cutworm Field Guide
Climbing cutworm adults – from Cutworm Field Guide

In terms of scouting, economic thresholds and control options, treat both species as you would bertha armyworms.

Bertha armyworm – adult
Alberta Agriculture and Rural Development
Clover cutworm adult
cc-by-nc-sa 2.0 Ilona Loser

To learn more about bertha armyworms and clover cutworms, go to the Insect of the Week page or download copies of the Field Crop and Forage Pests andtheir Natural Enemies in Western Canada and Cutworm Pests of Crops onthe Canadian Prairies identification field guides.

Cutworms

Cutworms (Noctuidae) – Still important this week to scout for cutworms!! Access Wk05 for help!  

Cutworms

Cutworms (Noctuidae) – A field guide is available to help growers scout and manage Cutworms.  Cutworm Pest of Crops is available for free in either English or French and is posted on the Cutworm Field Guide page!  

Several species of cutworms can be present in fields (Refer to downloadable PDF below).  They range in colour from shiny opaque, to tan, to brownish-red with chevron patterning.  Cutworm biology, species information, plus monitoring recommendations are available in the Prairie Pest Monitoring Network’s Cutworm Monitoring Protocol.  Also refer to Manitoba Agriculture cutworm fact sheet which includes action and economic thresholds for cutworms in several crops. 

In 2018, the Insect of the Week featured two economically important species of cutworms and some of the important natural enemies that help regulate these pests:

Scout fields that are “slow” to emerge, are missing rows, include wilting or yellowing plants, have bare patches, or appear highly attractive to birds – these are areas warranting a closer look.  Plan to follow-up by walking these areas later in the day when some cutworm species move above-ground to feed.  Start to dig below the soil surface (1-5 cm deep) near the base of a symptomatic plant or the adjacent healthy plant.  If the plant is well-established, check within the crown in addition to the adjacent soil.  The culprits could be wireworms or cutworms.  

CutwormSeasonalChart_Floate

For Albertans….. If you find cutworms, please consider using the Alberta Pest Surveillance Network’s “2019 Cutworm Reporting Tool” then view the live 2019 cutworm map which is updated daily.

Cutworms

Cutworms (Noctuidae) – A field guide is now available to help growers scout and manage Cutworms!  Cutworm Pest of Crops is available for free in either English or French and is posted on the Cutworm Field Guide page!  

Several species of cutworms can be present in fields.  They range in colour from shiny opaque, to tan, to brownish-red with chevron patterning.  Cutworm biology, species information, plus monitoring recommendations are available in the Prairie Pest Monitoring Network’s Cutworm Monitoring Protocol.  Also refer to Manitoba Agriculture cutworm fact sheet which includes action and economic thresholds for cutworms in several crops. 

Scout fields that are “slow” to emerge, are missing rows, include wilting or yellowing plants, have bare patches, or appear highly attractive to birds – these are areas warranting a closer look.  Plan to follow-up by walking these areas later in the day when some cutworm species move above-ground to feed.  Start to dig below the soil surface (1-5 cm deep) near the base of a symptomatic plant or the adjacent healthy plant.  If the plant is well-established, check within the crown in addition to the adjacent soil.  The culprits could be wireworms or cutworms.  

For Albertans….. If you find cutworms, please consider using the Alberta Pest Surveillance Network’s “2019 Cutworm Reporting Tool” then view the live 2019 cutworm map which is updated daily.

Cutworms

Cutworms (Noctuidae) – A field guide is available to help growers scout and manage Cutworms!  Cutworm Pest of Crops is available for free in either English or French and is posted on the Cutworm Field Guide page!  Also be sure to check the Insect of the Week through May – it highlights cutworms.  

Several species of cutworms  can be present in fields.  They range in colour from shiny,  opaque, to tan, to brownish-red with chevron patterning.  Cutworm biology, species information, plus monitoring recommendations are available in the Prairie Pest Monitoring Network’s Cutworm Monitoring Protocol.  Also refer to Manitoba Agriculture cutworm fact sheet which includes action and economic thresholds for cutworms in several crops. 

Scout fields that are “slow” to emerge, are missing rows, include wilting or yellowing plants, have bare patches, or appear highly attractive to birds – these are areas warranting a closer look.  Plan to follow-up by walking these areas later in the day when some cutworm species move above-ground to feed.  Start to dig below the soil surface (1-5 cm deep) near the base of a symptomatic plant or the adjacent healthy plant.  If the plant is well-established, check within the crown in addition to the adjacent soil.  The culprits could be wireworms or cutworms.  

The following page extracted from the new “Cutworm Pests of Crops on the Canadian Prairies” (Floate 2017; Page 5) shows the seasonal occurrence of lifecycle stages for different species of cutworms.  To aid scouting, the seasonal chart outlines what time of year larvae of different pest species are present (i.e., when to scout) but it also describes larval feeding habit (i.e., where to look for them relative to the plant host). 

 


For Albertans….. If you find cutworms, please consider using the Alberta Pest Surveillance Network’s “2018 Cutworm Reporting Tool”.  Once data entry occurs, growers can view the live 2018 cutworm map which is updated daily (see below for screenshot of map retrieved June 5, 2018).

Cutworms

Cutworms (Noctuidae) – A field guide is now available to help growers scout and manage Cutworms!  Cutworm Pest of Crops is available for free in either English or French and is posted on the Cutworm Field Guide page!  Also be sure to check the Insect of the Week through May – it highlights cutworms.  

Several species of cutworms  can be present in fields.  They range in colour from shiny,  opaque, to tan, to brownish-red with chevron patterning.  Cutworm biology, species information, plus monitoring recommendations are available in the Prairie Pest Monitoring Network’s Cutworm Monitoring Protocol.  Also refer to Manitoba Agriculture cutworm fact sheet which includes action and economic thresholds for cutworms in several crops. 

Scout fields that are “slow” to emerge, are missing rows, include wilting or yellowing plants, have bare patches, or appear highly attractive to birds – these are areas warranting a closer look.  Plan to follow-up by walking these areas later in the day when some cutworm species move above-ground to feed.  Start to dig below the soil surface (1-5 cm deep) near the base of a symptomatic plant or the adjacent healthy plant.  If the plant is well-established, check within the crown in addition to the adjacent soil.  The culprits could be wireworms or cutworms.  


The following page extracted from the new “Cutworm Pests of Crops on the Canadian Prairies” (Floate 2017; Page 5) shows the seasonal occurrence of lifecycle stages for different species of cutworms.  To aid scouting, the seasonal chart outlines what time of year larvae of different pest species are present (i.e., when to scout) but it also describes larval feeding habit (i.e., where to look for them relative to the plant host). 









For Albertans….. If you find cutworms, please consider using the Alberta Pest Surveillance Network’s “2018 Cutworm Reporting Tool”.  Once data entry occurs, growers can view the live 2018 cutworm map which is updated daily (see below for the map retrieved May 24, 2018).


Insect of the Week – Ground beetles: cutworm natural enemies

This week’s Insect of the Week is a large group of insects called ground beetles, also known as carabid beetles. Many species feed on cutworms as well as other pests.

Almost 400 different species of ground beetles occur on the Prairies, ranging in size from just a few millimetres to more than 2 centimetres. A field may contain 50 or more species, with densities ranging up to 10 beetles per square meter.

Ground beetles are characterized with long threadlike antennae, have a body that is flattened top-to-bottom, and have strong legs designed for running, large eyes, and obvious jaws (mandibles). Smaller ground beetle species can be important predators of cutworm eggs. Larger species attack and kill fully-grown cutworm larvae.
With all the work they do protecting your crop, ground beetles are real @FieldHeroes.
Find out more about ground beetles at the Insect of the Week page!
Adult Carabus nemoralis attacking a bertha armyworm caterpillar. 
Photocredit – Vincent Hervet, Agriculture and Agri-Food Canada
Species of ground beetles common in agricultural fields on the Prairies. 
From left to right: Bembidion quadrimaculatum, Agonum cupreum, 
Pterostichus melanarius, Calosoma calidum
Photocredit – Henri Goulet (retired), Agriculture and Agri-Food Canada

For a detailed review of ground beetle research, biology, distribution, habitat, diet, etc., see Chapter 1: Ground Beetles (Coleoptera: Carabidae) of the Prairie Grasslands of Canada.
**NEW – Don’t forget there’s a new cutworm identification manual you can download from the Cutworm Field Guide page – NEW**

 

Cutworms

Cutworms (Noctuidae) – A field guide is now available to help growers scout and manage Cutworms!  Cutworm Pest of Crops is available for free in either English or French and is posted on the Cutworm Field Guide page!  Also be sure to check the Insect of the Week through May – it highlights cutworms.  

Several species of cutworms  can be present in fields.  They range in colour from shiny opaque, to tan, to brownish-red with chevron patterning.  Cutworm biology, species information, plus monitoring recommendations are available in the Prairie Pest Monitoring Network’s Cutworm Monitoring Protocol.  Also refer to Manitoba Agriculture cutworm fact sheet which includes action and economic thresholds for cutworms in several crops. 

Scout fields that are “slow” to emerge, are missing rows, include wilting or yellowing plants, have bare patches, or appear highly attractive to birds – these are areas warranting a closer look.  Plan to follow-up by walking these areas later in the day when some cutworm species move above-ground to feed.  Start to dig below the soil surface (1-5 cm deep) near the base of a symptomatic plant or the adjacent healthy plant.  If the plant is well-established, check within the crown in addition to the adjacent soil.  The culprits could be wireworms or cutworms.  

For Albertans….. If you find cutworms, please consider using the Alberta Pest Surveillance Network’s “2018 Cutworm Reporting Tool”.  Once data entry occurs, growers can view the live 2018 cutworm map which is updated daily (see below for the map retrieved May 15, 2018).



Insect of the Week – Darksided cutworm

It’s spring, so it’s cutworm season. This week’s insect is the darksided cutworm. Mature larvae are hairless, greyish with a prominent white stripe on either side just above their legs. It is a climbing cutworm with feeding occurring at night. They have a broad host range including cereals, canola, corn, flax, sunflower, vegetables berry and tree fruits.

Find out more about the darksided cutworm at the Insect of the Week page.  Other important species include dingy, army, redbacked and pale western cutworms (See Insect of the Week: 2017 – May 1, 8, 15 and 29).

Darksided cutworm
Photocredit John Gavloski, Manitoba Ministry of Agriculture

In addition, Cutworm Pests of Crops on the Canadian Prairies – Identification and Management Field Guide was recently published (2017). This new handy manual has chapters on general biology, history of outbreaks, scouting techniques, natural enemies and general control options. The meat of the manual is descriptions of 24 cutworm species, their lifecycle, hosts, damage, monitoring and economic thresholds. To download a copy, go to the Cutworm Field Guide page.

Cutworms

Cutworms (Noctuidae) – A field guide is now available to help growers scout and manage Cutworms!  Cutworm Pest of Crops is available for free in either English or French and is posted on the Cutworm Field Guide page!  Also be sure to check the Insect of the Week through May – it highlights cutworms.  


Several species of cutworms  can be present in fields.  They range in colour from shiny opaque, to tan, to brownish-red with chevron patterning.  Cutworm biology, species information, plus monitoring recommendations are available in the Prairie Pest Monitoring Network’s Cutworm Monitoring Protocol.  Also refer to Manitoba Agriculture cutworm fact sheet which includes action and economic thresholds for cutworms in several crops. 

Scout fields that are “slow” to emerge, are missing rows, include wilting or yellowing plants, have bare patches, or appear highly attractive to birds – these are areas warranting a closer look.  Plan to follow-up by walking these areas later in the day when some cutworm species move above-ground to feed.  Start to dig below the soil surface (1-5 cm deep) near the base of a symptomatic plant or the adjacent healthy plant.  If the plant is well-established, check within the crown in addition to the adjacent soil.  The culprits could be wireworms or cutworms.  

For Albertans….. If you find cutworms, please consider using the Alberta Pest Surveillance Network’s “2018 Cutworm Reporting Tool”.  Once data entry occurs, growers can view the live 2018 cutworm map which is updated daily.

Insect of the Week – Glassy cutworm

This week’s insect is the glassy cutworm. The larva is greyish-white, semi-translucent and shiny (i.e. glass-like) with a orange-brown head. Since it overwinters as a larva, it is active as soon as the ground thaws. It feeds underground and rarely come to the surface. Their main host crop are grasses but will also attack wheat and corn. Corn planted following wheat may be particularly at risk.

Find out more about the glassy cutworm at the Insect of the Week page.

Glassy cutworm
cc-by Joseph Berger, bugwood.org

Other important species include dingy, army, redbacked and pale western cutworms (See Insect of the Week: 2017 – May 1, 8, 15 and 29).

In addition, Cutworm Pests of Crops on the Canadian Prairies – Identification and Management Field Guide was just published (2017). This new handy field guide has chapters on general biology, history of outbreaks, scouting techniques, natural enemies and general control options. The guide includes descriptions of 24 cutworm species, their lifecycle, hosts, damage, monitoring and economic thresholds. To download a copy, go to the Cutworm Field Guide page.

Update from the field….

Many prairie growers have a cutworm or armyworm story of woe but this time around growers on Vancouver Island near Port Alberni contended with an unusual pest – True armyworm (Mythimna unipuncta) in high densities were eating up hay fields and pasture!  Thanks to Tracy Hueppelsheuser with the BC Ministry of Agriculture who shared this CTV news clip.


Remember the NEW Cutworm Field Guide is free and downloadable in 2017!

Weekly Update – Cutworms

Cutworms (Noctuidae) – NEW – Just in time for spring scouting!  A new field guide is now available to help growers scout and manage Cutworms!  Cutworm Pest of Crops is now available for free in either English or French and is featured at our new Cutworm Field Guide!  

Keep an eye on fields that are “slow” to emerge, are missing rows, include wilting or yellowing plants, have bare patches, or appear highly attractive to birds – these are areas warranting a closer look.  Plan to follow-up by walking these areas later in the day when some cutworm species move above-ground to feed.  Start to dig below the soil surface (1-5 cm deep) near the base of a symptomatic plant or the adjacent healthy plant.  If the plant is well-established, check within the crown in addition to the adjacent soil.  The culprits could be wireworms or cutworms.  


Several species of cutworms can be present in fields.  They range in colour from shiny opaque, to tan, to brownish-red with chevron patterning.  Cutworm biology, species information, plus monitoring recommendations are available in the Prairie Pest Monitoring Network’s Cutworm Monitoring Protocol.  Also refer to the Manitoba Agriculture cutworm fact sheet which includes action and economic thresholds for cutworms in several crops. 


For Albertans….. If you find cutworms, please consider using the Alberta Pest Surveillance Network’s “2017 Cutworm Reporting Tool”.  The map now has reports of pale western and redbacked cutworms in central and southern Alberta so view the live 2017 cutworm map.


Check the Insect of the Week – the month of May highlighted cutworms!  Be sure to read more about Pale western cutworms, Redbacked cutworms, Army cutwormsDingy cutworms.

Remember the NEW Cutworm Field Guide is free and downloadable in 2017!

Insect of the Week – Dingy cutworm

For many, seed isn’t even in the ground yet, but the cutworms are ready for it when it is. So the time to start scouting for cutworms is now! Even if it is too wet to seed, consider checking volunteer plants for cutworms or feeding damage. General cutworm monitoring protocols can be found on the Monitoring Protocols page. Species-specific protocols can be found in the new Cutworm Pests of Crops on the Canadian Prairies (see below for download details).


There are over 20 cutworm species that may cause economic damage to your crop, each with different feeding behaviour, preferred hosts and lifecycle. This is why species identification is so important: it helps growers understand what they are up against: determining how and when to scout, knowing whether the cutworm species is found above-ground (climbing) or below-ground, recognizing damage, choosing control options. Species also impacts the most appropriate time of day for monitoring and applying controls.


Action and economic thresholds do exist for many of the cutworm species – please use them. This will help control costs by eliminating unnecessary/un-economic sprays and reduce your impact on non-target insects – insects that include cutworm natural enemies that work in the background to control cutworm populations.


This week’s Insect of the Week is the dingy cutworm. This is an above ground climbing species. Crops are at greatest risk in the spring when partially mature larvae emerge to feed primarily on leaves. The name ‘dingy cutworm’ is generally applied to three closely related species with similar appearance and life cycles.


For more information about dingy cutworms, go to the Insect of Week page.

Dingy cutworm larva (cc John Gavioski, Manitoba Agriculture)


Remember the NEW Cutworm Field Guide is free and downloadable in 2017!

Weekly Update – Cutworms

Cutworms (Noctuidae) – NEW – Just in time for spring scouting!  A new field guide is now available to help growers scout and manage Cutworms!  Cutworm Pest of Crops is now available for free in either English or French and is featured at our new Cutworm Field Guide!  Also be sure to check the Insect of the Week throughout May – it highlights cutworms!  Be sure to read more about Dingy cutworms.


Dingy cutworm larva (cc John Gavloski, Manitoba Agriculture)

Several species of cutworms can be present in fields.  They range in colour from shiny opaque, to tan, to brownish-red with chevron patterning.  Cutworm biology, species information, plus monitoring recommendations are available in the Prairie Pest Monitoring Network’s Cutworm Monitoring Protocol.  Also refer to the Manitoba Agriculture cutworm fact sheet which includes action and economic thresholds for cutworms in several crops. 

Keep an eye on fields that are “slow” to emerge, are missing rows, include wilting or yellowing plants, have bare patches, or appear highly attractive to birds – these are areas warranting a closer look.  Plan to follow-up by walking these areas later in the day when some cutworm species move above-ground to feed.  Start to dig below the soil surface (1-5 cm deep) near the base of a symptomatic plant or the adjacent healthy plant.  If the plant is well-established, check within the crown in addition to the adjacent soil.  The culprits could be wireworms or cutworms.  


For Albertans….. If you find cutworms, please consider using the Alberta Pest Surveillance Network’s “2017 Cutworm Reporting Tool”.  The map now has reports of pale western and redbacked cutworms in central and southern Alberta so view the live 2017 cutworm map.


Remember the NEW Cutworm Field Guide is free and downloadable in 2017!

Insect of the Week – Army cutworm

For many, seed isn’t even in the ground yet, but the cutworms are ready for it when it is. So the time to start scouting for cutworms is now! Even if it is too wet to seed, consider checking volunteer plants for cutworms or feeding damage. General cutworm monitoring protocols can be found on the Monitoring Protocols page. Species-specific protocols can be found in the new Cutworm Pests of Crops on the Canadian Prairies (see below for download details).


There are over 20 cutworm species that may cause economic damage to your crop, each with different feeding behaviour, preferred hosts and lifecycle. This is why species identification is so important: it helps growers understand what they are up against: determining how and when to scout, knowing whether the cutworm species is found above-ground (climbing) or below-ground, recognizing damage, choosing control options. Species also impacts the most appropriate time of day for monitoring and applying controls.


Action and economic thresholds do exist for many of the cutworm species – please use them. This will help control costs by eliminating unnecessary/un-economic sprays and reduce your impact on non-target insects – insects that include cutworm natural enemies that work in the background to control cutworm populations.


This week’s Insect of the Week is the army cutworm. This is an above ground species. Young larvae chew holes in leaves and notch leaf margins. Older larvae will consume entire leaves. They get their name from the fact that when food is scarce, larvae move as a large group in the same direction to locate more host plants.


For more information about army cutworms, go to the Insect of Week page.

Army cutworm larva (cc-by 3.0 Whitney Cranshaw, bugwood.org)

Remember the NEW Cutworm Field Guide is free and downloadable in 2017!

Weekly Update – Cutworms

Cutworms (Noctuidae) – NEW – Just in time for spring scouting!  A new field guide is now available to help growers scout and manage Cutworms!  Cutworm Pest of Crops is now available for free in either English or French and is featured at our new Cutworm Field Guide!  Also be sure to check the Insect of the Week throughout May – it highlights cutworms!  Be sure to read more about Army cutworms.

Army cutworm larva (cc-by 3.0 Whitney Cranshaw, bugwood.org)


Several species of cutworms  can be present in fields.  They range in colour from shiny opaque, to tan, to brownish-red with chevron patterning.  Cutworm biology, species information, plus monitoring recommendations are available in the Prairie Pest Monitoring Network’s Cutworm Monitoring Protocol.  Also refer to the Manitoba Agriculture cutworm fact sheet which includes action and economic thresholds for cutworms in several crops. 

Keep an eye on fields that are “slow” to emerge, are missing rows, include wilting or yellowing plants, have bare patches, or appear highly attractive to birds – these are areas warranting a closer look.  Plan to follow-up by walking these areas later in the day when some cutworm species move above-ground to feed.  Start to dig below the soil surface (1-5 cm deep) near the base of a symptomatic plant or the adjacent healthy plant.  If the plant is well-established, check within the crown in addition to the adjacent soil.  The culprits could be wireworms or cutworms.  


For Albertans….. If you find cutworms, please consider using the Alberta Pest Surveillance Network’s “2017 Cutworm Reporting Tool”.  Once data entry occurs, growers can view the live 2017 cutworm map which is updated daily.


Remember the NEW Cutworm Field Guide is free and downloadable in 2017!

Insect of the Week – Redbacked cutworm

For many, seed isn’t even in the ground yet, but the cutworms are ready for it when it is. So the time to start scouting for cutworms is now! Even if it is too wet to seed, consider checking volunteer plants for cutworms or feeding damage. General cutworm monitoring protocols can be found on the Monitoring Protocols page. Species-specific protocols can be found in the new Cutworm Pests of Crops on the Canadian Prairies (see below for download details).

There are over 20 cutworm species that may cause economic damage to your crop, each with different feeding behaviour, preferred hosts and lifecycle. This is why species identification is so important: it helps growers understand what they are up against: determining how and when to scout, knowing whether the cutworm species is found above-ground (climbing) or below-ground, recognizing damage, choosing control options. Species also impacts the most appropriate time of day for monitoring and applying controls.

Action and economic thresholds do exist for many of the cutworm species – please use them. This will help control costs by eliminating unnecessary/un-economic sprays and reduce your impact on non-target insects – insects that include cutworm natural enemies that work in the background to control cutworm populations.

This week’s Insect of the Week is the redbacked cutworm. This is an above ground species. Young larvae feed on newly-emerging shoots and furled leaves, creating small holes. Older larvae cut off leaves and sever plants just below the soil surface. Occasionally, the larvae pull the plants underground to feed on them.

For more information about Redbacked Cutworms, go to the Insect of Week page.

Redbacked cutworms – John Gavloski, Manitoba Agriculture

Remember the NEW Cutworm Field Guide is free and downloadable in 2017!

Weekly Update – Cutworms

Cutworms (Noctuidae) – NEW – Just in time for spring scouting!  A new field guide is now available to help growers scout and manage Cutworms!  Cutworm Pest of Crops is now available for free in either English or French and is featured at our new Cutworm Field Guide!  Also be sure to check the Insect of the Week throughout May – it highlights cutworms!  Be sure to read more about Redbacked cutworms.

Figure 1. Redbacked cutworms retrieved from a Manitoban field (Photo: J. Gavloski)

Several species of cutworms  can be present in fields.  They range in colour from shiny opaque, to tan, to brownish-red with chevron patterning.  Cutworm biology, species information, plus monitoring recommendations are available in the Prairie Pest Monitoring Network’s Cutworm Monitoring Protocol.  Also refer to the Manitoba Agriculture cutworm fact sheet which includes action and economic thresholds for cutworms in several crops. 

Keep an eye on fields that are “slow” to emerge, are missing rows, include wilting or yellowing plants, have bare patches, or appear highly attractive to birds – these are areas warranting a closer look.  Plan to follow-up by walking these areas later in the day when some cutworm species move above-ground to feed.  Start to dig below the soil surface (1-5 cm deep) near the base of a symptomatic plant or the adjacent healthy plant.  If the plant is well-established, check within the crown in addition to the adjacent soil.  The culprits could be wireworms or cutworms.  

For Albertans….. If you find cutworms, please consider using the Alberta Pest Surveillance Network’s “2017 Cutworm Reporting Tool”.  Once data entry occurs, growers can view the live 2017 cutworm map which is updated daily.


Remember the NEW Cutworm Field Guide is free and downloadable in 2017!

Insect of the Week – Pale western cutworm

For many, seed isn’t even in the ground yet, but the cutworms are ready for it when it is. So the time to start scouting for cutworms is now! Even if it is too wet to seed, consider checking volunteer plants for cutworms or feeding damage. General cutworm monitoring protocols can be found on the Monitoring Protocols page. Species-specific protocols can be found in the new Cutworm Pests of Crops on the Canadian Prairies (see below for download details).

There are over 20 cutworm species that may cause economic damage to your crop, each with different feeding behaviour, preferred hosts and lifecycle. This is why species identification is so important: it helps growers understand what they are up against: determining how and when to scout, knowing whether the cutworm species is found above-ground (climbing) or below-ground, recognizing damage, choosing control options. Species also impacts the most appropriate time of day for monitoring and applying controls.

Action and economic thresholds do exist for many of the cutworm species – please use them. This will help control costs by eliminating unnecessary/un-economic sprays and reduce your impact on non-target insects – insects that include cutworm natural enemies that work in the background to control cutworm populations.

This week’s Insect of the Week is the Pale Western Cutworm. This is a below-ground feeder. Larvae hatch in late April/early May. As they feed on/tunnel through shoots as they pass through the soil, young larvae produce holes on newly-emerged shoots and furled leaves . Older larvae will sever plants just below the soil surface and may pull and eat the severed shoots underground.

For more information about Pale Western Cutworm, go to the Insect of Week page.

Pale western cutwom. cc-by-nc 3.0 Frank Peairs,
Colorado State University, bugwood.org

Remember the NEW Cutworm Field Guide is free and downloadable in 2017!

Weekly Update – Cutworms

Cutworms (Noctuidae) – NEW – Just in time for spring scouting!  A new field guide is now available to help growers scout and manage Cutworms!  Cutworm Pest of Crops is now available for free in either English or French and is featured at our new Cutworm Field Guide!  Also be sure to check the Insect of the Week throughout May – it highlights cutworms through May.  Be sure to read more about Pale western cutworms.



Several species of cutworms  can be present in fields.  They range in colour from shiny opaque, to tan, to brownish-red with chevron patterning.  Cutworm biology, species information, plus monitoring recommendations are available in the Prairie Pest Monitoring Network’s Cutworm Monitoring Protocol.  Also refer to Manitoba Agriculture and Rural Initiatives cutworm fact sheet which includes action and economic thresholds for cutworms in several crops. 


Keep an eye on fields that are “slow” to emerge, are missing rows, include wilting or yellowing plants, have bare patches, or appear highly attractive to birds – these are areas warranting a closer look.  Plan to follow-up by walking these areas later in the day when some cutworm species move above-ground to feed.  Start to dig below the soil surface (1-5 cm deep) near the base of a symptomatic plant or the adjacent healthy plant.  If the plant is well-established, check within the crown in addition to the adjacent soil.  The culprits could be wireworms or cutworms.  

For Albertans….. If you find cutworms, please consider using the Alberta Pest Surveillance Network’s “2017 Cutworm Reporting Tool”.  Once data entry occurs, growers can view the live 2017 cutworm map which is updated daily.


Remember the NEW Cutworm Field Guide is free and downloadable in 2017!

NEW Cutworm Identification and Management Field Guide

Cutworms are part of Canadian agriculture on the Prairies. Most of the time they are of little concern but outbreaks do occur from time to time, causing significant economic damage if not controlled. Cutworm outbreaks can range from small patches of clipped or missing plants in individual fields to widespread areas with entire quarter
sections needing re-seeding



Cutworm management starts with identification – knowing what species is at work in your fields helps unlock information
that improves cutworm scouting and management. Knowledge of cutworm 
biology, behaviour, preferred habitat, impacts of weather and interaction with its natural enemies will all improve scouting
techniques and pest management decisions for growers. 



Just released, the Cutworm Pests of Crop on the Canadian Prairies – Identification and Management Field Guide describes the economically important cutworm pests in detail and provides the information needed to manage them. [Funding for preparation of this publication was provided by the Canola Council of Canada]

For more information and a download link, go to our Cutworm Field Guide.

Insect of the Week – Cotesia margeniventris

Cotesia margeniventris (parasitoid)

Last year, the focus of the Insect of the Week was crop pests. This year, we’re changing things up and highlighting the many natural enemies that help you out, silently and efficiently killing off crop pests. [note: featured Insects of the Week in 2015 are available on the Insect of the Week page] 

This week’s Insect of the Week is Cotesia marginiventris (sorry, no common name), a braconidid wasp parasitoid. Female C. marginiventris lay their eggs in the larvae of cabbage looper, black cutworm, corn earworm, variegated cutworm, armyworm and fall armyworm.


For more information about C. marginiventris, the pests it controls and other important crop and forage insects, see the new Field Crop and Forage Pests and their Natural Enemies in Western Canada – Identification and Management Field Guide for identification, life cycle and conservation options (download links for field guide available on the Insect of the Week page).

Cotesia marginiventris parasitoidizing beet armyworm larva.
Photo cc-by-nc Debbie Waters, University of Georgia, Bugwood.org