WESTERN BEAN CUTWORM – WILL THE RANGE EXPANSION REACH THE PRAIRIES?

Western bean cutworm (Striacosta albicosta) is a native North American insect that, at high levels, can be a pest of corn and dry beans. However, the way they feed is different than some of the other cutworms many may be familiar with. Western bean cutworm feeds on the reproductive parts of plants (corn tassel, silks, and kernels, or dry bean pods and seeds). This can result in yield loss, and spread ear mold. In Ontario, injury by western bean cutworm has been shown to increase mycotoxin production in grain corn.

Range Expansion: The historical geographic range of the western bean cutworm covered the western Great Plains states including Colorado, Nebraska, and Wyoming but, over the past two decades, its distribution has been more easterly rather than north to the prairies. A report from the 1950s of western bean cutworm in Alberta has instead been confirmed as a misidentification of another species. Currently, it has not been detected in the Canadian prairie provinces. Since 1999, the geographic range of the western bean cutworm has rapidly expanded eastward across the U.S. Corn Belt and eastern Canada. Western bean cutworm adults have been collected in 22 additional states and provinces since 1999, spreading from western Iowa to the east coast of the United States and Canada. It was first found in Canada in Ontario in 2008. Keep an eye open for this insect when scouting for crop pests in corn or dry beans this summer.

Figure 1. Detailed expansion of western bean cutworm distribution into the eastern Corn Belt between 2000 and 2017. From: Smith et al. 2019. Journal of Integrated Pest Management. Volume 10, Issue 1, pg. 1-19.

Appearance and monitoring tips:
Larvae:
• There are six stages (instars) of the larvae, and appearances vary.
• Older larvae are a light tan colour, with an orange head. The pronotum (the shield-like structure just behind the head) has two broad dark brown stripes.
• You may find young larvae on the silks of corn. Older larvae may be on the ears of corn, but you may have to peel back the husks to find them (Fig. 2).

Figure 2. Western bean cutworm feeding on corn. Photo: Jocelyn Smith, University of Guelph.


Adults:
• Each forewing has a white or tan band running along the edge or margin of the wing (Fig. 3). Inside this band are 2 distinctive markings: a brown circle and a brown kidney bean shape, both surrounded by a tan border.
Note – Other moths across the Canadian prairies, such as redbacked cutworm, have similar markings.

Figure 3. Western bean cutworm adult. Photo: Jocelyn Smith, University of Guelph.

Please help – When monitoring in the Canadian prairies, adults or larvae suspected to be western bean cutworm can be directed to your provincial entomologist for species verification. New and confirmed sightings of this species are important and will help mobilize research and pest management strategies.

Additional information on western bean cutworm can be found in the publication “Western Bean Cutworm” by the Canadian Corn Pest Coalition: https://cornpest.ca/corn-pests/western-bean-cutworm/

Did you know? Bt corn with the Vip3A protein effectively controls western bean cutworm, but some of the Bt corn products for European corn borer will not.

Reference:
Ecology and Management of the Western Bean Cutworm (Lepidoptera: Noctuidae) in Corn and Dry Beans—Revision With Focus on the Great Lakes Region. 2019. J. L. Smith, C. D. Difonzo, T. S. Baute, A. P. Michel, and C. H. Krupke, Journal of Integrated Pest Management, Volume 10, Issue 1: 1-19.

EUROPEAN CORN BORER: A GENERALIST PEST OF CROPS

Despite its common name, the European corn borer (Ostrinia nubilalis) feeds on many crop and non-crop plants including beans, potato, quinoa, millet, hemp, wheat, many vegetables and some flowers. European corn borer is occasionally an economic pest of crops such as corn and potatoes in Manitoba, where there is one generation per year. In parts of Ontario and eastern Canada, there are univoltine (one generation per year) and bivoltine (two generations per year) strains. How prevalent and damaging European corn borer is to many of its host crops is still not clear.

European corn borer has traditionally been monitored in corn fields, and more recently in potato fields. However, a new harmonized protocol can be used to monitor for European corn borer in multiple crops. Anyone participating in insect monitoring on any potential host crop can access the harmonized protocol online or using the Survey123 app.

The protocol can be used to report the presence of European corn borer eggs, larvae, and crop damage. Anyone monitoring populations or encountering noticeable levels of European corn borer or their injury to any crop is highly encouraged to add this data. For more information about the harmonized protocol and to submit monitoring data, please click here to access all needed links. Information collected from across Canada will be used to better understand the distribution, feeding habits, and abundance of this pest.

European Corn Borer egg masses. Photo credit: John Gavloski, Manitoba Agriculture

Access these resources to find more information:
• Review the European corn borer page within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (2018) also accessible as a free downloadable PDF in either English or French on our new Field Guides page.
• Review the Manitoba Agriculture fact sheet for the European corn borer.
• Review the Ontario Ministry of Agriculture, Food, and Rural Affairs fact sheet for European corn borer.

Nationwide monitoring pilot project for European corn borer

The European corn borer (ECB; Ostrinia nubilalis), has been an important pest of corn and other crops in eastern Canada for nearly a century now but is also known to be a sporadic pest in western Canada. Despite its name, ECB is actually a generalist feeder, having a wide range of hosts. With so many new emerging crops being grown in Canada that are also hosts for ECB (eg. hemp, cannabis, quinoa, hops, millet and others), there is no better time to look at this pest across the Canadian agricultural landscape.

To monitor for ECB nationwide, the Surveillance Working Group of the Canadian Plant Health Council has developed a harmonized monitoring protocol for European corn borer in both English and French. The project aims to generate real-time reporting and annual maps – access a full description of the project and list of key contact persons. The protocol can be used to report ECB eggs, larvae or damage in any host crop across Canada. This harmonized protocol has been designed to complement protocols already in use to make management decisions in order to generate data to compare ECB presence across all of Canada and across host crops.

When scouting corn, quinoa, hemp, millet, potatoes, apples, or other crops susceptible to ECB, the Surveillance Working Group of the Canadian Plant Health Council encourages the use of the harmonized monitoring protocol and reporting of the data from fields or research plots using the free Survey123 app (available for both desktop and mobile devices):
• Early to Mid-Season ECB Survey (Before July) – https://arcg.is/0qCCHH (applicable for use in eastern Canada).
• Later Season ECB Survey (July to Pre-Harvest) – https://arcg.is/fSODf (applicable for use in both eastern AND western Canada).

Nationwide monitoring pilot project for European corn borer

The European corn borer (ECB; Ostrinia nubilalis), has been an important pest of corn and other crops in eastern Canada for nearly a century now but is also known to be a sporadic pest in western Canada. Despite its name, ECB is actually a generalist feeder, having a wide range of hosts. With so many new emerging crops being grown in Canada that are also hosts for ECB (eg. hemp, cannabis, quinoa, hops, millet and others), there is no better time to look at this pest across the Canadian agricultural landscape.

To monitor for ECB nationwide, the Surveillance Working Group of the Canadian Plant Health Council has developed a harmonized monitoring protocol for European corn borer in both English and French. The project aims to generate real-time reporting and annual maps – access a full description of the project and list of key contact persons. The protocol can be used to report ECB eggs, larvae or damage in any host crop across Canada. This harmonized protocol has been designed to complement protocols already in use to make management decisions in order to generate data to compare ECB presence across all of Canada and across host crops.

When scouting corn, quinoa, hemp, millet, potatoes, apples, or other crops susceptible to ECB, the Surveillance Working Group of the Canadian Plant Health Council encourages the use of the harmonized monitoring protocol and reporting of the data from fields or research plots using the free Survey123 app (available for both desktop and mobile devices):
• Early to Mid-Season ECB Survey (Before July) – https://arcg.is/0qCCHH (applicable for use in eastern Canada).
• Later Season ECB Survey (July to Pre-Harvest) – https://arcg.is/fSODf (applicable for use in both eastern AND western Canada).

Doppelgangers: Cereal leaf beetle vs. Collops beetles

The case of the innocuous versus the evil twin: When making pest management decisions, be sure that the suspect is actually a pest. This can be challenge since insects often mimic each other or look very similar. An insect that looks, moves and acts like a pest may in fact be a look-alike or doppelganger.

Doppelgangers may be related (e.g. same genus) or may not be related, as in the case of monarch butterflies (Danaus plexippus) and viceroys (Limenitis achrippus).  Doppelgangers are  usually relatively harmless but sometimes the doppelganger is a pest yet their behaviour, lifecycle or hosts may be different.

Correctly identifying a pest enables selection of the most accurate scouting or monitoring protocol. Identification and monitoring enables the application of economic thresholds. It also enables a producer to select and apply the most effective control option(s) including method and timing of application.  For the rest of the growing season, the Insect of the Week will feature insect crop pests and their doppelgangers.

The case of the cereal leaf beetle versus Collops beetles: 

Cereal leaf beetle, Boris Loboda

Cereal leaf beetles (Oulema melanopus), both adults and larva, feed on leaves (oat, barley, wheat, corn, etc), but it is the larval damage that can reduce yield and quality, especially if the flag leaf is stripped. Adults are 6-8 millimeters (.25-.31 inches) long with reddish legs and thorax (middle section between head and abdomen) and metallic bluish-black head and elytra (wing coverings).

Collops beetle, cc-by-nd-nc 1.0 Ashley Bradford

They may be confused with beneficial beetles belonging to the Collops genus (adults feed on aphids, stink bug eggs, moth eggs, small caterpillars, spider mites, whiteflies). Roughly the same size, they may have a red or orange thorax with/without red markings on their elytra, depending on the species. One consistent feature that will help distinguish between the two species is that the cereal leaf beetle elytra are smooth and shiny whereas the Collops’ elytra are covered in hairs.

Specific information on the cereal leaf beetle can be found in the updated Field Crop and Forage Pests and their Natural enemies in Western Canada field guide.

Review previously featured insects by visiting the Insect of the Week page.

Invasive species: Brown marmorated stink bug

This week’s Insect of the Week is the brown marmorated stink bug (Halyomorpha halys). Stink bugs get their name from the foul odour they release when threatened. Brown marmorated stink bug is not known to be established in the Prairies, but the species has been found in the Southern Interior of BC, in Ontario and Quebec. Feeding causes damage to seeds and seed pods, reducing yield. Nymphs and adults prefer field corn and soybean, but infestations have been reported on rape, pea, sunflower and cereals in the USA. They have also been known to attack tree fruits, berries, vegetables and many ornamental trees and shrubs.

Brown marmorated stink bug – adult (CC-BY 2.0 Katja Schulz)

Additional information and fact sheets for this insect have been posted by Ontario Ministry of Agriculture, Food, and Rural Development, and BC Ministry of Agriculture and Seafood. You can also check out our Insect of the Week page.

This insect is featured in our Field Crop and Forage Pests and their Natural Enemies Field Guide which is available for download from the Insect Field Guide page. 

Insect of the Week – Twospotted spider mite (Acarina: Tetranychus)

This week’s Insect of the Week is the twospotted spider mite. This tiny mite is 0.5 mm long and has eight legs. It has a greenish, yellowish to orange oval body with two dark spots on its abdomen. To the unaided eye, it looks like a small speck. they feed on corn, soybean, dry beans, alfalfa, vegetables and fruit.

These mites overwinter in protected sites as eggs, immatures or adults depending on food hosts and habitat. Immatures and adults move to emerging plant hosts in the spring. They create webbing on the underside of leaves where they puncture cells to feed on cell contents. This feeding causes stippling, yellowing or browning of the leaves. Leaves may dry and drop which can further reduce crop yields.

Infestations start at the field edge and move inwards. Extended hot, dry conditions favour rapid population build up and exacerbate feeding injury.

For more information on the twospotted spider mite, check out our Insect of the Week page!

Twospotted spider mite – adult closeup
David Cappaert, Michigan State University, Bugwood.org
Twospotted spider mite – stippling damage on bean
Whitney Cranshaw, Colorado State University, Bugwood.org

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.

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.

Winter Update – True armyworm

Earlier this summer (Week 14), the true armyworm (Lepidoptera: Noctuidae: Mythimna unipunctawas reported on the lower west coast and a summary was provided by Tracy Hueppelsheuser (BC Ministry of Agriculture).

Tracy kindly provided an update to the situation…. The initial true armyworm damage reported earlier did not relent and a second generation of voracious larvae continued to cause damage in late August through to late September in southwestern British Columbia.  In addition to Vancouver Island (hit a second time), true armyworm larvae showed up south of Abbotsford, Sumas, Matsqui, Dereoche, as well as east through Chilliwack (Greendale, Rosedale), and west all the way to Delta and Westham Island.  The outbreak resulted in damage to grass fields and even corn was defoliated and cobs damaged!  

True armyworm pupae were observed mid-September and moths are expected over the next while in lower BC.  A third generation is anticipated but is not expected to cause as much damage owing to the cooler nights (~8°C) which should slow insect development and feeding.  Parasitism was noted which is good news in terms of natural enemies responding to the outbreak.  Also, lots of bird feeding activity has been observed although the birds’ seeking and feeding activities have also damaged grass fields!

The outbreak of true armyworm in lower BC appears to be part of a larger outbreak that has similarly afflicted western Oregon and Washington this year.  

Find more information on true armyworms in the NEW Cutworm Field Guide, free and downloadable in 2017!


Screenshots of true armyworm from the Cutworm Field guide are also shown below:




Insect of the Week – Cereal leaf beetle

This week’s Insect of the Week is the cereal leaf beetle. Wheat is their preferred host, but they also feed on oats, barley, corn, rye, triticale, reed canarygrass, ryegrass, fescue, wild oats, millet and other grasses. Adults and larvae feed on the leaf tissue of host plants. Yield quality and quantity is decreased if the flag leaf is stripped. It is also interesting to note that larvae carry all of their own fecal waste with them as protection from predators.


For more information on the cereal leaf beetle, see our Insect of the Week page.



Cereal leaf beetle larva (cc-by 2.0 Christophe Quintin)




Cereal leaf beetle damage (cc-by-nc-sa 2.0 CIMMYT)



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

Weekly Update – Small scarab beetle

Small scarab beetle (Coleoptera: Aphodius distinctus) – This is the time of summer that farmers will be seeing larvae of a small scarab beetle (Aphodius distinctus) in their fields.  There have been scattered reports each June of large numbers of beetle grubs in crops associated with crop damage (e.g., canola, corn, dry bean, onion, pea).


Please help researchers compile information related to this species so they might confirm its pest status!  Information is posted about the beetle and the survey.  Here’s how you can help:


1. Please send reports of high white grub densities and associated crop damage to Kevin.Floate@agr.gc.ca (403-317-2242). 


2. Live larvae accompanied by the following field information would be extremely helpful please – contact Dr. Kevin Floate if you have a sample!


3. Include answers to the following so the pest status for this species can be ascertained:  
     – Previous crop?
     – Legal land location or latitude+longitude?
     – Irrigated or not?
     – Was composted manure added this spring?
     – Surface residue in spring?

Insect of the Week – Tetrastichus julis

Tetrastichus julis (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 Tetrastichus julis (sorry, no common name), an important cereal leaf beetle parasitoid. Where T. julis has become established, it can reduce cereal leaf beetle populations by 40 – 90%, preventing yield loss without using pesticides. See also the factsheet, Biological Control at its Best, Using the T. julis Wasp to Control the Cereal Leaf Beetle (French version).


For information about the cereal leaf beetle (p. 24) and other pests and their natural enemies, 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).

T. julis adult parasitizing a cereal leaf beetle larva 
– Swaroop Kher, University of Alberta/AAFC