Entomologist Dr. Kevin Floate aims to answer ‘what critters are found in a cow patty?’ and ‘what do they do?’ His hope is to spark the interest of ranchers and farmers, and to stir the minds of students studying insects. In his own words, ‘This is the guide I wish I had when I started my career.’
Cover and sample content of Cow Patty Critters
Insects serve an outsized role in many ecosystem services. For dung on Canadian pastures, there are over 300 species of insects helping to break down and cycle nutrients through the soil and food webs. Understanding what insects are present in a cow patty provides insights into livestock health and ecological processes.
Dr. Kevin Floate speaking about insects to a captivated audience. Photo credit: Cam Goater, University of Lethbridge
Download your copy of Cow Patty Critters in English or in French.
This new 224-page, full color guide provides the ‘doorway’ to learn more about the critters one can find in cow dung: how to identify them, how they can be beneficial, and additional information on the biology and morphology of multiple insect groups. Also included is an extensive reference list for those who wish to pursue detailed insect identification.
Continuing our series on Prairie wireworms, this week we highlight the sugarbeet wireworm, Limonius californicus.
This species is less abundant than Hypnoidus bicolor or the Prairie grain wireworm (Selatosomus aeripennisdestructor), but some fields have a major problem with this species. Limonius californicus wireworms are 17-22 mm long at maturity and can be aggressive feeders. The literature reports it is more likely to be found in irrigated fields.
The life cycle of L. californicus on the Prairies is not well known. Our current information is based on lab studies in California in the 1940s, where larvae lived for 2-5 years before undergoing metamorphosis into adult click beetles.
Wireworm size varies within a species depending on age. Photo: W. van Herk, AAFC-Agassiz
AAFC has recently released a new field guide on Prairie pest wireworms. It has information on biology, monitoring and management, and research on wireworms on the Prairies. Preview pages extracted from the guide highlighting Limonius californicus by clicking here.
Free digital copies in both official languages can be downloaded at these links:
Free hard copies are also available while supplies last. Email Haley Catton at haley.catton@agr.gc.ca to request your copy.
Did you know?
– A new pheromone has recently been discovered by researchers at Simon Fraser University AAFC that attracts male beetles. This pheromone will help monitoring efforts.
References:
Gries R, Alamsetti SK, van Herk WG, Catton HA, Meers S, Lemke E, Gries G (2021) Limoniic acid – major sex pheromone component of the click beetles Limonius canus and L. californicus. Journal of Chemical Ecology 41:123-133. https://doi.org/10.1007/s10886-020-01241-y
Van Herk, W. G., Labun, T. J., & Vernon, R. S. (2019). Efficacy of diamide, neonicotinoid, pyrethroid, and phenyl pyrazole insecticide seed treatments for controlling the sugar beet wireworm, Limonius californicus (Coleoptera: Elateridae), in spring wheat. Journal of the Entomological Society of British Columbia, 115, 86-100.
Continuing our series on Prairie wireworms, this week we highlight the Prairie grain wireworm, Selatosomus aeripennis destructor.
This species is native to the Prairies and is the second most abundant wireworm in Prairie crop fields, but it likely causes the most damage. This wireworm is big and beefy, it grows up to 23 mm long when mature and has a stout build. Its aggressive feeding style can destroy 10 times as many seeds as its cousin, Hypnoidus bicolor, a species that is often found together within the same fields.
Size of resident wireworms can vary with species. Selatosomus aeripennis destructor (left) and Hypnoidus bicolor (right). Photo: W. van Herk, AAFC Agassiz . Photo taken from the Pest Wireworm Guide
Interestingly, click beetles of this species rarely fly, they mostly walk to find mates and choose locations to lay eggs. A new pheromone has recently been discovered by researchers at Simon Fraser University and AAFC that can be used to attract male beetles. This pheromone will help monitoring efforts.
AAFC has recently released a new field guide on Prairie pest wireworms. It has information on biology, monitoring and management and research on wireworms on the Prairies.
Free digital copies in both official languages can be downloaded at these links.
See this week’s wireworm information in the free, downloadable guide: English ; French
Did you know?
Prairie grain wireworm has a closely-related subspecies called Puget sound wireworm (Selatosomus aeripennis aeripennis). This species looks almost identical to Prairie grain wireworm and can be a pest in the Aspen Parkland Ecoregion.
Reference:
Gries, R., van Herk, W., Alamsetti, S.K., Catton, H., Meers, S., Otani, J., Gries, G. (2022) (Z,E)-a-Farnesene – sex pheromone component of female click beetle Selatosomus aeripennis destructor (Brown) with intra- and inter-sexual communication function. Entomologia Experimentalis et Applicata. 170:344-351. https://doi.org/10.1111/eea.13142
Continuing our series on Prairie wireworms, this week we highlight Hypnoidus bicolor.
This species is the most abundant in Prairie crop fields and is a native species. Despite its abundance, it has no common name. Hypnoidus bicolor larvae are relatively small (10-12 mm long when mature) and are often found in the same fields as next week’s PPMN Insect of the Week, Prairie grain wireworm (Selatosomus aeripennis destructor, up to 23 mm long when mature).
Size of resident wireworms can vary with species. Selatosomus aeripennis destructor (left) and Hypnoidus bicolor (right). Photo: W. van Herk, AAFC-Agassiz
Although this species is abundant, it may not be as aggressive of a feeder than its cousin the Prairie grain wireworm. An interesting feature of this species is that it has different populations, some of which are all females. What we call H. bicolor today may actually be several species or subspecies based on genetic differences. We estimate that the larvae of this species live in the soil for 2-3 years but this has not been verified.
AAFC has recently released a new field guide on Prairie pest wireworms. It has information on biology, monitoring and management and research on wireworms on the Prairies. Preview the Hypnoidus bicolor pages of the new wireworm guide here.
Free digital copies in both official languages can be downloaded at these links.
Free hard copies are also available while supplies last. Email Haley Catton at haley.catton@agr.gc.ca to request your copy.
Main pest wireworm species on the Canadian Prairies: larval stages (top), adult (click beetle) stages (bottom). Photos: J. Saguez, CEROM
Did you know ?
– H. bicolor is in the same genus as the main pest species in Quebec, the abbreviated wireworm Hypnoidus abbreviatus.
Reference:
Drahun, I., Wiebe, K.F., Koloski, C.W., van Herk, W.G. and Cassone, B.J. (2021), Genetic structure and population demographics of Hypnoidus bicolor (Coleoptera: Elateridae) in the Canadian Prairies. Pest Manag Sci, 77: 2282-2291. https://doi.org/10.1002/ps.6255
Cutworm scouting spans April to late June across the Canadian prairies! 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 either very early or late in the day when some cutworm species (or climbing cutworms) move above-ground to feed. Start to dig below the soil surface (1-5 cm deep) near the base of symptomatic plants and also any healthy plants immediately adjacent to missing rows or wilting or clipped plants. Some cutworms feed by remaining just below the soil surface, clipping then pulling the plant below as they munch away! If the plant is well-established (e.g., perennial grass or legume), check within the crown in addition to the adjacent soil. The culprits could be cutworms, wireworms, or more!
Important: Several species of cutworms (Lepidoptera: Noctuidae) can be present in fields. They range in colour from shiny opaque, to tan, to brownish-red with chevron patterning. A field guide is available to help growers scout and manage the various species of cutworms that can appear in field crops grown on the Canadian prairies. Cutworm Pest of Crops is available free in either English or French! Download a searchable PDF copy to access helpful diagnostic photos plus a table showing which larvae are active at different points in the growing season!
Other vital resources to scout and manage cutworms include:
● For anyone on the Canadian prairies, Manitoba Agriculture and Rural Development’s Cutworms in Field Crops fact sheet includes action and economic thresholds for cutworms in several crops, important biological information, and great cutworm photos to support in-field scouting.
● For Albertans….. If you find cutworms, please consider using the Alberta Insect Pest Monitoring Network’s “2022 Cutworm Reporting Tool” then view the live 2022 cutworm map updated daily. Review the live map to see where cutworms are appearing then prioritize in-field scouting accordingly.
The Pests and Predators Field Guide is filled with helpful images for quick insect identification and plenty of tips to manage the pests AND natural enemies in your fields. Claim your free copy at http://fieldheroes.ca/fieldguide/ or download a free copy to arm your in-field scouting efforts!
Review the Sweep-net Video Series including: • How to sweep a field. Meghan Vankosky (Agriculture and Agri-Food Canada-Saskatoon). Published online 2020. • What’s in my sweep-net? Meghan Vankosky (Agriculture and Agri-Food Canada-Saskatoon). Published online 2020. • Why use a sweep-net? Meghan Vankosky (Agriculture and Agri-Food Canada-Saskatoon). Published online 2020.
Wireworms are the larvae of click beetles (Coleoptera: Elateridae). They are serious pests of many field crops across Canada, particularly cereals, pulses, root crops. Wireworms live for multiple years in the soil, eating crops from below – their underground habitat can make them difficult to detect and diagnose. Damage in cereals and pulse crops will appear as early season crop thinning or yellowing, weakened plants. Root crops may look fine aboveground but at harvest, produce will have feeding holes or disfigurations, decreasing market value.
When crop thinning is seen, post-emergence scouting by digging up plants and soil can reveal if wireworms are there. Photos: H. Catton, AAFC-Lethbridge.
There are several pest wireworm species in the Prairies and they are different than in other regions of Canada. A 2004-2019 survey of Prairie crop fields published by Wim van Herk and colleagues collected 5,704 specimens. This survey revealed that 97% of specimens belonged to 4 native species: 58% were Hypnoidus bicolor (no common name), 22% were Prairie grain wireworm (Selatosomus aeripennis destructor), 15% were sugarbeet wireworm (Limonius californicus), and 2% were flat wireworm (Aeolus mellillus). Importantly, the invasive wireworm species dominating coastal BC and the Atlantic provinces (Agriotes obscurus, Agriotes lineatus, Agriotes sputator) were NOT found in the survey. Over the next several weeks our Insect of the Week articles will highlight the main pest wireworm species on the Prairies.
Main pest wireworm species on the Canadian Prairies: larval stages (top), adult (click beetle) stages (bottom). Photos: J. Saguez, CEROM
Monitoring for wireworms can be done in different ways. Before seeding, bait traps can be placed in the soil. After crop emergence, hand digging in thinned areas of crop may reveal wireworms. Finally, monitoring for adult click beetles may be able to indicate if wireworm populations are high – this method is still in development. Unfortunately, there are no economic thresholds developed for wireworms, farmers need to judge yield loss from thin or bare patches caused by wireworms.
AAFC has recently released a new field guide on Prairie pest wireworms. It has information on biology, monitoring and management and research on wireworms on the Prairies.
Free digital copies in both official languages can be downloaded at these links.
Free hard copies are also available while supplies last. Email haley.catton@agr.gc.ca to request your copy.
Reference:
van Herk WG, Vernon RS, Labun TJ, Sevcik MH, Schwinghamer TD (2021) Distribution of pest wireworm (Coleoptera: Elateridae) species in Alberta, Saskatchewan, and Manitoba (Canada). Environmental Entomology 50:663-672. doi: 10.1093/ee/nvab006
Reminder – Field scouting is critical – it enables the identification of potential risks to crops. Accurate identification of insect pests PLUS the application of established monitoring methods will enable growers to make informed pest management decisions.
We offer TWO generalized insect pest scouting charts to aid in-field scouting on the Canadian prairies:
Whenever possible, monitor and compare pest densities to established economic or action thresholds to protect and preserve pollinators and beneficial arthropods. Economic thresholds, by definition, help growers avoid crop losses related to outbreaking insect pest species.
Reminder – One last time for this growing season….. We have updated the field scouting charts so they now link to pages within the 2018 version of the Insect Field Guide.
We offer TWO generalized insect pest scouting charts to aid in-field scouting on the Canadian prairies:
Whenever possible, monitor and compare pest densities to established economic or action thresholds to protect and preserve pollinators and beneficial arthropods. Economic thresholds, by definition, help growers avoid crop losses related to insect pest species but they rely on in-field scouting!
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
Whenever possible, monitor and compare pest densities to established economic or action thresholds to protect and preserve pollinators and beneficial arthropods. Economic thresholds, by definition, help growers avoid crop losses related to outbreaking insect pest species.
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)
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.
Field scouting is critical – it enables the identification of potential risks to crops. Accurate identification of insect pests PLUS the application of established monitoring methods will enable growers to make informed pest management decisions.
We offer TWO generalized insect pest scouting charts to aid in-field scouting on the Canadian prairies:
Whenever possible, monitor and compare pest densities to established economic or action thresholds to protect and preserve pollinators and beneficial arthropods. Economic thresholds, by definition, help growers avoid crop losses related to outbreaking insect pest species.
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.orgTwospotted spider mite – stippling damage on bean Whitney Cranshaw, Colorado State University, Bugwood.org
This week’s Insects of the Week are the natural enemies (@FieldHeroes) of the wheat stem sawfly, namely Bracon cephi (Gahan) and B. lissogaster (Hymenoptera: Braconidae).
Nine species of parasitic wasps are known to attack wheat stem sawfly but Bracon cephi and B. lissogaster are the main species that help regulate this pest in North America. These closely related wasp species are described as idiobiont ectoparasitoids meaning the parasitoid larva, after hatching from an egg laid on the surface of the sawfly larva, feeds on the exterior of the host. Normally, both Bracon species will complete their development (i.e., pupates) inside the wheat stem within the integument of the sawfly larva or just beside the consumed host. There are two generations of B. cephi and B. lissogaster per year. The first generation normally completes its lifecycle then escapes from the wheat stem to locate a new sawfly larva to parasitize. The second generation of these wasps will overwinter within the wheat stem.
These wasps are 2-15 mm long and are usually brown in colour. They have a narrow waist connecting the abdomen to the thorax and the combined length of head plus thorax is equal to the length of the abdomen. These parastiod wasps have long antennae and two pairs of transparent wings. Females have a noticeable ovipositor protruding from the end of the abdomen.
For more information about the natural enemies of the wheat stem sawfly, check out our Insect of the Week page!
The English grain aphid (Sitobion avenae) has started to appear across the Prairies in various cereal crops this past week so the time to scout is now. Look for this aphid infesting wheat heads (favourite host) as well as barley, oat, rye, Timothy and canaryseed.
This aphid can also be a vector for barley yellow dwarf virus. You might see the green, red colour morph or both morphs in fields this year (Fig. 1). You will probably also see ladybeetle (@FieldHeroes) adults and larvae hunting the aphids (Fig. 2). The economic threshold for aphids in spring wheat in Western Canada is 12-15 aphids per head prior to the soft dough stage.
Agriculture and Agri-Food Canada, with funding from the Pest Management Centre, has developed a smartphone app called Cereal Aphid Manager (CAM) to facilitate scouting for aphids in cereals that also allows you to record the beneficial insects in the field that can keep aphid populations below the economic threshold – available at Apple iTunes and Google Play app stores. CAM information and download links.
For more information on the English grain aphid, check out our Insect of the Week page!
Submitted by Dr. Tyler Wist (Tyler.Wist@agr.gc.ca).
Fig. 1 Green and red morph English grain aphid (Tyler Wist, AAFC)Fig. 2 Seven-spotted lady bird larva hunting aphids (Tyler Wist, AAFC)
This week’s Insect of the Week is the wheat stem sawfly (Cephus cinctus). Adults are 8-13mm long and have a shiny, black, wasp-like body and yellow legs. When at rest on plant stems, they point their heads downwards.
Mature larvae overwinter in the base of stems in infested fields. In June, females emerge and fly to nearby wheat crops, where they can lay up to 50 eggs each on stems.
The wheat stem sawfly feeds primarily on spring and durum wheat, though winter wheat, rye, grain corn, barley, and some native grasses can support sawfly development. It cannot develop on oats.
Larvae feed on the pith of host plants stems which can cause a reduction in crop yield and quality. When plants mature, larvae move to the bottom of the stem to overwinter.
For more information about the wheat stem sawfly, head over to our Insect of the Week page!
This week’s Insects of the Week are two parasitoid wasps, an Inostemma sp. (Hymenoptera: Platygastridae) and a Gastrancistus sp. (Hymenoptera: Pteromalidae). These parasitoids are natural enemies of the canola flower midge (Contariniabrassicola, Diptera: Cecidomyiidae), a newly discovered fly species that uses canola as its host plant. The parasitoids have been found throughout the Prairies emerging from infested galls created by the canola flower midge. Little is known about these two species, but parasitism rates as high as 30% have been noted in northeast Saskatchewan.
Populations of pea aphids, Acyrthosiphon pisum Harris (Hemiptera: Aphididae), can be kept below the economic threshold by their natural enemies if these are present early and in sufficient numbers. Natural enemies include parasitoids, predators, and diseases that reduce pest populations.
Predators of pea aphids include ladybird beetles (adults and larvae), syrphid fly larvae, and damsel bugs. These predators catch and eat pea aphids of all ages and sizes. They are classified as generalists because they also prey on other insect species.
Harlequin ladybeetle larva (Photo: cc by-sa Quartl)
Pea aphids are attacked by several species of parasitoid, including Aphidius ervi Haliday (Hymenoptera: Aphidiidae: Aphidiinae). Female parasitoids lay individual eggs inside aphid nymphs. After hatching, the parasitoid larva consumes its host, eventually killing it. The parasitoid pupates inside the dead or mummified aphid before a new adult parasitoid emerges.
Aphid mummies look bloated and discoloured compared to healthy adult aphids. Parasitism rates can be estimated by counting the number of aphid mummies on five host plants at five locations within a field.
Aphidius ervi parasitoid (Photo: cc by Penny Greeves)
For more information about the predators and parasitoids of pea aphids, visit the Insect of the Week page or consult Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Management Field Guide.
To learn more about some of the natural enemies fighting pests in background for free, go to www.fieldheroes.ca or follow @FieldHeroes on Twitter.
Blog post submitted by Dr. Meghan Vankosky. Follow her at @Vanbugsky.
If you haven’t downloaded the FREE field guide yet, please do so now!
Field Crop and Forage Pests and their Natural Enemies in Western Canada: IDENTIFICATION AND MANAGEMENT FIELD GUIDE
The 152-page, full-colour field guide, now available online, is designed to help you make informed decisions in managing over 90 harmful pests of field and forage crops in Western Canada. Better decision making helps save time and effort and eliminates unnecessary pesticide applications to improve your bottom line. The guide also helps the reader identify many natural enemies that prey on or parasitize pest insects. Recognizing and fostering populations of natural enemies will enhance their role in keeping or reducing pest populations below economic levels.
This week’s insect of the week is the pea aphid (Acyrthosiphon pisum). This long-legged, pear-shaped aphid is 3-4 mm long, light to dark green and each antennal segment is tipped by a black band. It feeds on field peas, alfalfa, broad beans, chickpeas, clover and lentils. Feeding damage can reduce yields due to lower seed formation and seed size. Leaves may turn yellow and overall plant growth can be delayed.
Pea aphids overwinter as eggs on the leaves and stems of perennial legumes (eg. clover or alfalfa crowns). They produce 2-3 generations asexually before winged females migrate to summer host crops where several more generations are produced. Winged sexual forms develop in late summer that mate and females return to winter host crops to lay eggs.
If you haven’t downloaded the FREE field guide yet, please do so now!
Field Crop and Forage Pests and their Natural Enemies in Western Canada: IDENTIFICATION AND MANAGEMENT FIELD GUIDE
The 152-page, full-colour field guide, now available online, is designed to help you make informed decisions in managing over 90 harmful pests of field and forage crops in Western Canada. Better decision making helps save time and effort and eliminates unnecessary pesticide applications to improve your bottom line. The guide also helps the reader identify many natural enemies that prey on or parasitize pest insects. Recognizing and fostering populations of natural enemies will enhance their role in keeping or reducing pest populations below economic levels.
The insect of the week is the Bruner grasshopper (Melanoplus bruneri). Observed since the 1920s in Canada, this species is a relatively recent addition to the list of grasshopper pest species occurring in crop production areas. Previously, it was not considered a crop pest.
It is a medium-sized grasshopper (males 18-22 mm; females 22-27 mm) with dark and often reddish colour tones. It is similar in appearance and size to the migratory grasshopper (Melanoplus sanguinipes) but is distinguished by differences in the male genitalia. The Bruner grasshopper has recently become the predominant grasshopper species in many northern crop production areas of Alberta and parts of Saskatchewan. It occupies a wide geographic range and is found throughout much of Canada and the United States.
The Bruner grasshopper feeds mainly on broadleaf host plants but the species can feed upon several species of grasses. It has been observed in high numbers feeding in pulse crops, canola, and cereals.
Researchers are investigating if this species follows a two-year life cycle (i.e. do eggs require exposure to two winters before hatching?) in the Peace River region and parts of central Alberta.
This week’s Insect of the week is the red turnip beetle (Coleoptera: Chrysomelidae). This beetle is 7-10 millimeters long and has a distinctive red body with black markings on the head and thorax, and three black stripes down its back (elytra). They feed on mustards, canola, cole crops, and cruciferous weeds (except stinkweed).
They overwinter as reddish brown oval eggs in the soil. Adults emerge in the spring to feed for 2-3 weeks before re-entering the soil to escape the summer heat. When they re-emerge, they disperse throughout the host crop, feeding, mating, and laying eggs (300-400/female). Feeding damage can cause delayed harvest or need for re-seeding to replace killed plants. Later in the season they feed on leaves, stems, and pods. Attached pods are prone to premature shelling.
For more information about the red turnip beetle, have a look at our Insect of the Week page!
Red turnip beetle adult and damage John Gavloski, Manitoba Agriculture, Food and Rural Development
This week’s insect is the ground beetle, Pterostichus melanarius (Coleoptera: Carabidae). This large (12-19 mm), shiny black beetle originates from Europe and probably arrived to North America in the 1920s in ships’ ballasts. It has become a widespread insect throughout North America, particularly in habitats used by humans: urban areas, forests, and agricultural land.
Flight has been the main method of colonization and dispersal for this species. In newly arrived populations of P. melanarius, individuals generally have longer hind wings which allow for more efficient dispersal. After a population has become established in an area, short-winged morphs of the species become dominant.
This species is an excellent example of a generalist predator. Generalist predators include many species of ground beetles, some rove beetles, ants, centipedes and spiders. These arthropods are not picky when it comes to choosing a meal. For example, P. melanarius will eat nearly anything including many different arthropods, earthworms, slugs and even some small vertebrates. Generalist predators are effective in keeping some insects from reaching high numbers that can damage agricultural crops.
Find out more about ground beetles and Pterostichus melanarius at the Insect of the Week page!
Pterostichus melanarius Photo credit: Henri Goulet (retired), Agriculture and Agri-Food Canada
Photograph of Pterostichus melanarius catching a fourth-instar P. xylostella in a plastic container (LRC, Photo credit: A. Mauduit)
This week’s Insect of the Week is a frustrating pest of many crops: wireworm. Wireworms are the soil-dwelling larval stage of the click beetles (Elateridae). There are hundreds of click beetle species in the prairies, but the term wireworm refers to those that are pests, which in Canada is approximately 20 species. With the loss of effective insecticides (e.g. lindane), wireworms have re-emerged in recent years as primary pests of potato, cereals, and vegetables. On the prairies, we have 3 predominant pest species (Selatosomus destructor, Limonius californicus, and Hypnoidus bicolor; see photo), and their larvae vary (among other things) in life history (2-7 years), color (white to orange), cuticle thickness, distribution, behaviour, and susceptibility to insecticides.
Wireworms are patchy in distribution, difficult to monitor, and difficult to kill. We have a lot to learn about these resilient pests. Since the mid-1990’s AAFC has had a national research team (Bob Vernon et al.) screening for effective insecticides and developing trapping and monitoring methods, cultural controls (e.g., crop rotation), and biocontrols to manage the adult and larval forms of these pests.
For more information about wireworms, check out our Insect of the Week page!
The three most troublesome wireworm species on the prairies in their adult and larval stages. Note the different sizes and colours. From left to right, S. destructor, L. californicus, H. bicolor. Photo by David Shack, AAFC-Lethbridge.
This week’s Insect of the Week is the Flea Beetle (Phyllotreta species). This group of beetles is typically oval and 2-3 mm long. In canola, the most common flea beetles are either bluish black (crucifer flea beetle or Phyllotreta cruciferae) or black with two wavy yellow lines running down the length of its back (striped flea beetle or Phyllotreta striolata). They overwinter as adults under plant material along field margins and females lay eggs in the soil near the host plants. Striped and crucifer flea beetles feed on canola, mustard and related cruciferous plants and weeds. Their damage results in a shot-hole appearance in cotyledon leaves. They also feed on stems under windy or damp conditions, causing wilting or breakage. Remember, the Action Threshold for flea beetles on canola is when 25% of cotyledon leaf area is consumed.
For more information on flea beetles, refer to the Insect of the Week page!
Field scouting is critical – it enables the identification of potential risks to crops. Accurate identification of insect pests PLUS the application of established monitoring methods will enable growers to make informed pest management decisions. We offer TWO generalized insect pest scouting charts to aid in-field scouting on the Canadian prairies: 1. CANOLA INSECT SCOUTING CHART 2. A NEW FLAX INSECT SCOUTING CHART These charts feature hyperlinks directing growers to downloadable PDF pages within the “Field crop and forage pests and their natural enemies in western Canada: Identification and management field guide“. Whenever possible, monitor and compare pest densities to established economic or action thresholds to protect and preserve pollinators and beneficial arthropods. Economic thresholds, by definition, help growers avoid crop losses related to outbreaking insect pest species. Good luck with your scouting!
Field scouting is critical – it enables the identification of potential risks to crops. Accurate identification of insect pests PLUS the application of established monitoring methods will enable growers to make informed pest management decisions. We offer TWO generalized insect pest scouting charts to aid in-field scouting on the Canadian prairies: 1. CANOLA INSECT SCOUTING CHART 2. A NEW FLAX INSECT SCOUTING CHART These charts feature hyperlinks directing growers to downloadable PDF pages within the “Field crop and forage pests and their natural enemies in western Canada: Identification and management field guide“. Whenever possible, monitor and compare pest densities to established economic or action thresholds to protect and preserve pollinators and beneficial arthropods. Economic thresholds, by definition, help growers avoid crop losses related to outbreaking insect pest species. Good luck with your scouting!
Field scouting is critical – it enables the identification of potential risks to crops. Accurate identification of insect pests PLUS the application of established monitoring methods will enable growers to make informed pest management decisions. We offer TWO generalized insect pest scouting charts to aid in-field scouting on the Canadian prairies: 1. CANOLA INSECT SCOUTING CHART 2. A NEW FLAX INSECT SCOUTING CHART These charts feature hyperlinks directing growers to downloadable PDF pages within the “Field crop and forage pests and their natural enemies in western Canada: Identification and management field guide“. Whenever possible, monitor and compare pest densities to established economic or action thresholds to protect and preserve pollinators and beneficial arthropods. Economic thresholds, by definition, help growers avoid crop losses related to outbreaking insect pest species. Good luck with your scouting!
Earlier this summer (Week 14), the true armyworm (Lepidoptera: Noctuidae: Mythimna unipuncta) was 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:
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. 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. They are not known to be established in the Prairies, but have been found in the BC Southern Interior, Ontario and Quebec. Feeding causes damage to seeds and seed pods, reducing yield.
Brown marmorated stink bug – adult (CC-BY 2.0 Katja Schulz)
This week’s Insect of the Week is the bronzed blossom pollen beetle. They feed on canola and oilseed rape, mustards, bittercress, rockcress, wild radish and dogmustard. They are not known to be established in Western Canada, but are present in Nova Scotia, PEI and Quebec. Adult females lay clusters of 2 to 3 eggs in developing buds and can lay up to 250 eggs in one summer. Once the eggs hatch, larva enter developing flower buds to feed. This feeding can reduce seed production by up to 70%!
For more information on the bronzed blossom pollen beetle, see our Insect of the Week page.
This week’s Insect of the Week is the red clover casebearer moth. As it’s name suggests, its primary host is red clover, but larvae also reportedly feed on alsike, stone, white and zig-zag clover. The mature larvae are contained within portable cases made of withered flower petals and silk and they feed from the front end of the case on developing seed in the floret. They can consume up to three seeds per day. In areas with high numbers of these moths, such as the Peace River region in BC and AB, red clover stands should only be grown for one year in rotation.
For more information on the red clover casebearer moth, visit our Insect of the Week page.
This week’s Insect of the Week is the soybean aphid. This pest overwinters in the US and is blown into Canada, where winged females migrate to soybeans and produce several generations over the summer.
In 2016, 2.5 million acres of soybeans were planted in Alberta, Saskatchewan, and Manitoba. This amount is expected to rise in coming years. Thus, it is important to know how to scout for and manage soybean aphids.
For more information on soybean aphids, visit our Insect of the Week page.
Soybean aphid – adult (Robert J. O’Neil, Purdue University (wiki))
This week’s Insect of the Week is the group of aphids known
as cereal aphids. These aphids include the corn leaf aphid, the English grain
aphid, the oat-birdcherry aphid and the Russian wheat aphid. They feed on
cereal crops and are vectors of viruses, causing lower crop quality and yield. There are several natural enemies of cereal aphids, including various species of wasps and beetles.
This week’s Insect of the Week is a beneficial wasp from the Family Pteromalidae named Macroglenes penetrans. It is an important natural enemy of wheat midge. The wasp is a parasitoid that lives within the wheat midge larva and overwinters within the host. In the spring, the parasitoid larva develops to emerge from the wheat midge cocoon buried in the soil and seeks out wheat midge eggs.
For more information about M. penetrans, see our Insect of the Week page.
Macroglenes penetrans – adult (AAFC)
Follow @FieldHeroes to learn more about Natural Enemies that are working for you for FREE to protect your crops!
This week’s Insect of the Week is the wheat midge. Larvae feed on the surface of developing wheat kernels in spring and winter wheat, durum wheat, triticale and occasionally spring rye. Damage includes aborted, shrivelled, misshapen, cracked, or scared kernels. This lowers grain yield, quality and grade.
For more information on the wheat midge, visit our Insect of the Week page.
This week’s Insect of the Week is the Rove Beetle (Delia spp.). This beetle feeds on aphids, mites, eggs and larvae of many other insects present under plant debris, rocks, stones, carrion, dung, and other materials. It is also an important natural enemy of the pea leaf weevil. One species of the rove beetle, Aleochara bilineata, is an important natural enemy of cabbage, seedcorn, onion and turnip maggots.
Follow @FieldHeroes to learn more about the Natural Enemies that are working for you for FREE to protect your crops!
For more information on the Rove Beetle, see our Insect of the Week page.
This week’s “Insect of the Week” is the Pea Leaf Weevil. Larval hosts are field peas and faba beans. Adults can spread to other cultivated and wild legumes, such as alfalfa, beans and lentils. Each adult female lays up to 300 eggs in one summer! The eggs hatch in the soil near developing plants and larvae move to feed on nitrogen-fixing nodules. This results in partial or complete inhibition of nitrogen fixation by the plant, causing poor plant growth. Adults feed on leaves and growing points of seedlings, causing notches in leaf margins.
Adult, larval and egg stages overlap and all three can be present over most of the growing season. For more information about Pea Leaf Weevil risk in your area, see the 2017 Insect Risk Maps page. Also, we have posted a NEW Pea Leaf Weevil monitoring protocol.
For more information on the pea leaf weevil, see the Insect of the Week page.
Pea leaf weevil – adult, eggs (Mike Dolinski, MikeDolinsky@hotmail.com)
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)
Field scouting is critical – it enables the identification of potential risks to crops. However, the identification of these insect pests PLUS the application of established monitoring methods will enable growers to make informed pest management decisions.
Whenever possible, monitor and compare pest densities to established economic or action thresholds to protect and preserve pollinators and beneficial arthropods. Economic thresholds, by definition, help growers avoid crop losses related to outbreaking insect pest species.
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
Field scouting is critical – it enables the identification of potential risks to crops. Field crop production systems across the Canadian prairies will suffer insect pest outbreaks. However, the identification of these insect pests PLUS the application of established monitoring methods will enable growers to make informed pest management decisions.
For 2017, we offer TWO generalized insect pest scouting charts to aid in-field scouting on the Canadian prairies:
Growers can access biological information about the pest and its natural enemies, the type of damage it causes, how to monitor, and what pest management strategies might apply to help protect yield and quality (Fig. 1).
Whenever possible, monitor and compare pest densities to established economic or action thresholds to protect and preserve pollinators and beneficial arthropods. Economic thresholds, by definition, help growers avoid crop losses related to outbreaking insect pest species.
Good luck with your scouting!
Figure 1. Example of Bertha armyworm pages from the above field guide:
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
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]
When encountering insects found in prairie crops, I quite often don’t know if I’ve found a ‘good’ or a ‘bad’ insect. In these instances, I feel like Glinda the Good when she asked Dorothy, ‘are you a good witch, or a bad witch?’ Some are ‘good’ insects (predators, parasitoids, pollinators, decomposers) and others are ‘bad’ (defoliators, sap suckers, seed eaters, root eaters, disease vectors). And of course there’s also the great grey middle where some insects have a balance of good and bad traits, while others are seemingly and completely benign. Many times, you can’t tell simply by their appearance which category an insect falls in (unlike Glinda in identifying a bad witch: ‘Only bad witches are ugly.’). Especially when you encounter their adult form as it’soften the larvae or nymphs that cause most of the damage.
AAFC entomologists
study many aspects of the insects that make their home in our crops and nearby
land. One of those aspects is how the ‘good’ insects contribute to the
producers’ bottom line in terms of the pest control services they provide. Economists estimate that for
every $1 invested in Integrated Pest Management research, the industry gets
back about $15 in benefits.For a brief look at some of the work AAFC
entomologists do in Saskatchewan, make some popcorn, sit back and watch our newvideo.
I would be remiss
if I didn’t add that AAFC entomologists partner with provincial, university, industry
and private entomologists in the region and across Canada to discover, monitor and
publicize the latest findings and trends in crop pests and beneficials.
You might also
like to take a look at ‘Field Crop and Forage Pests and their Natural Enemies
in Western Canada: Identification and Management Guide’ for information and
full colour pictures of important economic Prairie crop insects and spiders. Download
links are available on the ‘Insect of Week’ page.
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 theInsect of the Week page]
This week’s feature natural enemies are predatory mites. These are not insects but instead belong to the Arachnid or spider class of arthropods. My known encounters with mites have been of the pest type (e.g. two-spotted spider mite), spinning their webs and literally sucking the life out of their host plants and transmitting viruses. But this group, the predatory mites get their meal instead from insect eggs, all stages of pest mites, thrips, young aphids and leafhoppers. They may be small, but they are ‘mity’.
For more information about these natural enemies, other pests they control 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).
Adult whirligig mite,
Aleksander Balodis (AfroBrazillian), Wikimedia Commons
Last
year, the focus of the Beneficial 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 theInsect of the Week page]
This
week’s feature beneficial insect is the Assassin Bug. I love it when a common
name is so apt. Assassins (at least in the movies) are guns for hire and
they’ll take out whoever is on their list. They’re usually the bad guys but on
occasion can be a force for good (e.g.Jason Bourne). Similarly
in the insect world, assassin bugs are indiscriminate in who they attack,
preying on immature and adult forms of beneficials and pests alike by patiently
lying in wait for their target to come within stabbing distance.
For
more information about these natural enemies, other pests they control 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).
Assassin bug (Reduvius personatus), Keith Roragen, Flickr
Last year, the focus of the BeneficialInsect 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 theInsect of the Week page]
You can’t tell by looks whether an insect is a good bug (beneficial) or a bad bug (pest). And while you might recognize the adult, the immature form might appear quite alien. This is definitely the case with the ladybird beetle (aka lady beetle). This cute, orange, nearly round beetle with varying number of spots depending on species appears harmless but is a voracious eater, consuming up to 100 aphids a day (and other soft bodied insects). The larvae (slate blue, elongated body with varying black and yellow patterns) can be just as hungry.
One of the exciting projects at Agriculture Canada is looking at how natural enemies like ladybird beetles control cereal aphids in wheat, oat, barley and rye, preventing them from causing economic damage without you having to lift a finger (or hook up a sprayer). Of course, there are times when there aren’t enough free helpers/natural enemies and we’re developing an app that will help growers figure out if and when they need to control cereal aphids. (Refining and making accessible to growers a validated dynamic action threshold for cereal aphid control in cereal crops).
For more information about these natural enemies, other pests they control 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).
Last year, the focus of the BeneficialInsect 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 theInsect of the Week page]
Early in the season, cabbage seedpod weevil adults can cause canola flower budblasting as they feed on developing flowers and later in the season, they will feed on pods. However it’s the larvae that cause most of the damage by feeding on developing seeds; infested pods are also more prone to shattering and may have a higher incidence of fungal infections. To the rescue are tiny wasp parasitoids that attack the adults (e.g. Microtonus melanopus) and larvae (e.g. Trichomalus lucidus).
For more information about these natural enemies, other pests they control 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).
Trichomalus lucidus, a cabbage seedpod weevil parasitoid.
CC 3.0 BY-NC-SA CNC/BIO Photography Group, Biodiversity Institute of Ontario
Last year, the focus of the BeneficialInsect 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 theInsect of the Week page]
This week’sInsect of the Weekare Aphidiidae wasps*. While you won’t likely see them flying about attacking aphids, this tiny wasp can parasitoidize 100-350 aphids during its relatively short lifetime. The resulting aphid ‘mummy’ ceases causing crop damage and instead becomes a living host for the developing wasp. After 2 to 4 weeks of development, a new adult Aphidiidae wasp emerges and starts hunting for aphids to continue the cycle. To see an Aphidius avenaphis wasp in action, see:https://www.youtube.com/watch?v=T7PNlpEgvEM&feature=youtu.be.
For more information about this natural enemy, other pests they control 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).
* this wasp genus only attacks aphids, not humans.
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 Insects of the Week are crab spiders. These are generalist predators, capturing any insects (small flies, ants, bees, wasps, beetles, small moths, thrips)visiting flowers, including canola which is in full flower right now. They are called crab spiders because they walk sideways like a crab.
For more information about these spiders, the other pests they control 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).
‘Will you walk into my parlor?’ said the [yellow crab] spider to the fly
– (c) AAFC, Tyler Wist
Bertha armyworm parasitoids – Ichneumonids and Tachinids
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 Insects of the Week are tachinids, and ichneumonidae. The adult tachinid will feed on flower nectar, honeydew from aphids, scales, and mealybugs. The tachinid, Athrycia cinerea (Coq.), is a parasitoid of the Bertha armyworm. Ichneumonidae adults also eat nectar and aphid honeydow, however, its larvae (Banchus flavescens, Cresson) are parasitoids of Lepidoptera, Coleoptera, Diptera, Hymenoptera, and some spiders. For more information about these parasitoids, the other pests they control 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).
We again post our generalized canola scouting chart to aid in-field scouting on the Canadian prairies. The version below contains hyperlinks to help growers learn more about some of our insect pests and how to monitor for them.
Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide (2015) by Hugh Philip is a new publication from Agriculture and Agri-Food Canada. Two downloadable (~8 MB) versions of the complete field guide are available:
This week’s Insect of the Week is the Aphidius wasp (Aphidius sp.), Most people’s experience with wasps is a painful encounter with a paper wasp, hornet or yellow jacket. However, there are far more beneficial wasps than hurtful. The Aphidius wasp is just one of many such, with female wasps parasitizing up to 350 aphids during their short lifespan. Small but mighty, a large enough population of Aphidius wasps (working alone or together with other cereal aphid predators/parasitoides) can bring down a cereal aphid population to the point where spraying becomes unnecessary. See more information in 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).
This week’s Insect of the Week is the corn earworm (Helicoverpa zea), an annual migrant from Mexico and southern USA. According to Wikipedia, the corn earworm is the second most important economic insect pest in North America. See information from the new Field Crop and Forage Pests and their Natural Enemies in Western Canada – Identification and Management Field Guide for identification, life cycle and control options (download links for field guide available on the Insect of the Week page).
This week’s Insect of the week is an important aphid predator, the syrphid fly. Syrphid flies are more commonly known as hoverflies. There are many species in the Syrphidae family and the adults of several species mimic wasps.
Wasps are characterized by having two pairs of wings, a tightly tapered ‘waist’, long antennae, and a yellow and black body. In contrast, hoverflies or syrphid flies have one pair of wings, a less distinct ‘waist’, have short antennae, and an abdomen striped yellow and black or a black and brown body. Syrphid flies also have relatively large compound eyes characteristic to all Diptera spp. Mimicking the appearance of a wasp helps protect syrphid flies from predation. Find out more about hoverflies and more at the Insect of the Week page!
Two syrphid flies on a hawkweed flower.
(c) 2015 John Gavloski, Manitoba Agriculture, Food and Rural Development
Prairie Pest Monitoring Network Weekly Updates – August 12, 2015
Otani, Giffen, Svendsen, Olfert
Greetings! An HTML and PDF version of this Weekly Update can beaccessed here.
Weather synopsis – The following weather maps were retrieved from AAFC’s Drought Watch website. The map below shows the Highest Temperatures the Past 7 Days (July 29-August 10, 2015) across the prairies:
The map below shows the Accumulated Precipitation the past 7 days (i.e., July 29-August 10, 2015):
While the map below reflects the Accumulated Precipitation for the Growing Season (i.e., April 1-August 10, 2015):
The map below reflects the Percent of Normal Precipitation for the Growing Season (i.e., April 1-August 10, 2015) for comparison:
The updated growing degree day (GDD) (Base 5ºC, March 1 – August 9, 2015) map is below:
While the growing degree day (GDD) (Base 10ºC, March 1 – August 9, 2015) map is included below:
Pre-Harvest Interval (PHI) – Growers is late-season insect pest problems will need to remember to factor in the PHI which is the minimum number of days between a pesticide application and swathing or straight combining of a crop. The PHI recommends sufficient time for a pesticide to break down and a PHI-value is both crop- and pesticide-specific. Adhering to the PHI is important for a number of health-related reasons but also because Canada’s export customers of canola strictly regulate and test for the presence of trace residues of pesticides.
In 2013, the Canola Council of Canada created and circulated their “Spray to Swath Interval Calculator” which was intended to help canola growers accurately estimate their PHI. Other PHI are described in your provincial crop protection guides and remember that specific crop x pesticide combinations will mean different PHIs. A screen shot of the webpage is included below for your reference.
Bertha armyworm (Mamestra configurata) –In-field monitoring will focus on searching for Bertha armyworm larvae which will feed on leaves but also upon newly developing pods. Take care to examine the whole plant when scouting. Watch for the following life stages:
Reminder: Some bertha armyworm larvae remain green or pale brown throughout their larval life. Large larvae may drop off the plants and curl up when disturbed, a defensive behavior typical of cutworms and armyworms. Young larvae chew irregular holes in leaves, but normally cause little damage. The fifth and sixth instars cause the most damage by defoliation and seed pod consumption. Crop losses due to pod feeding will be most severe if there are few leaves. Larvae eat the outer green layer of the stems and pods exposing the white tissue. At maturity, in late summer or early fall, larvae burrow into the ground and form pupae.
Monitoring:
Sample at least three locations (a minimum of 50 m apart) within a field for larvae. At each location, mark an area of 1 m2 and beat the plants growing within that area to dislodge the larvae. Count them and compare the average against the values in the economic threshold table below:
Table 1. Economic thresholds for Bertha armyworm in canola (courtesy Manitoba Agriculture, Food and Rural Initiatives).
Expected Seed Value – $ / bushel*
Spraying cost –
$ / acre
6
7
8
9
10
11
12
13
14
15
16
Number of Larvae / metre2 *
7
20
17
15
13
12
11
10
9
9
8
8
8
23
20
17
15
14
13
11
11
10
9
9
9
26
22
19
17
16
14
13
12
11
10
10
10
29
25
22
19
17
16
14
13
12
11
11
11
32
27
24
21
19
17
16
15
14
13
12
12
34
30
26
23
21
19
17
16
15
14
13
13
37
32
28
25
22
20
19
17
16
15
14
14
40
35
31
27
24
22
20
19
17
16
15
15
43
37
32
29
26
23
22
20
19
17
16
* Economic thresholds for bertha armyworm are based on an assumed yield loss of 0.058 bu/acre for each larva/metre2 (Bracken and Bucher. 1977. Journal of Economic Entomology. 70: 701-705).
Diamondback Moth (Plutella xylostella) – In-field monitoring for DBM larvae should continue this week.
Larval Monitoring:
Once the diamondback moth is present in the area, it is important to monitor individual canola fields for larvae. 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 dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.
Remember, parasitoid wasps attacking DBM larvae (Refer to photo below) are already present in fields. Use the economic thresholds to preserve these beneficial wasps by NOT applying insecticide until DBM larval densities exceed the threshold.
Diamondback larva (upper left) and pupal silk cocoon (upper right), Diadegma insulare adult and early instar Diamondback moth larvae on canola leaf (lower left) and D. insulare pupae (N=2) within Diamondback moth pupal silk cocoons (lower right).
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).
Swede midge (Contarinia nasturtii) – Thank you to Dr. Lars Andreassen who provided the following update for swede midge monitoring in Saskatchewan for 2015. Very low swede midge numbers have been intercepted at pheromone trap monitoring sites across the prairies but these results are not surprising given the drought conditions. In-field surveying performed by Andreassen et al. (AAFC-Saskatoon) are mapped below for 2015. Their findings show consistent swede midge populations (larvae and damage symptoms) in northeast Saskatchewan in 2015. Note there are new records of larvae and swede midge damage at sites surrounding Lloydminster up against the Alberta border in 2015.
Reminder – Swede midge scouting tips for in-field monitoring:
Watch for unusual plant structures and plant discolourations then follow-up by closely scrutinizing the plant for larvae (Refer to Figure below for larvae among the anthers).
The growing tip may become distorted and produce several growing tips or none at all, young leaves may become swollen, crinkled or crumpled and brown scarring caused by larval feeding may be seen on the leaf petioles and stems.
Flowers may fail to open.
Youngplants that show unusual growth habits should be examined carefully for damageand larvae, especially if the sticky liners have many flies resembling midges (swede midges are about the size of orange blossom wheat midge but are not orange).
In 2014, Canola School posted a swede midge update entitled “ Swede midge a pest on the rise”, featuring Dr. Julie Soroka (AAFC-Saskatoon). The Ontario Canola Growers post swede midge information here. Dr. Rebecca Hallett has posted a very helpful swede midge identification guide for those performing in-field monitoring and pheromone trapping. Finally, canola management recommendations for swede midge in Ontario are posted by Rebecca Hallett and Brian Hall.
Cabbage seedpod weevil (Ceutorhynchus obstrictus) – There is one generation of CSPW per year and the overwintering stage is the adult which is an ash-grey weevil measuring 3-4mm long (Refer to lower left photo). Adults typically overwinter in soil beneath leaf litter within shelter belts and roadside ditches. They emerge from overwintering in the spring as soil temperatures warm to ~15°C. CSPW utilize several flowering hosts including wild mustard, flixweed, hoary cress, stinkweed and volunteer canola. CSPW move to canola during the bud to early flower stages and will feed on pollen and buds, causing flowers to die. Adult feeding damage to buds is more evident in dry years when canola is unable to compensate for bud loss. Adults mate following a pollen meal then the female will deposit a single egg through the wall of a developing pod or adjacent to a developing seed within the pod (refer to lower right photo). Eggs are oval and an opaque white, each measuring ~1mm long. Typically a single egg is laid per pod although, when CSPW densities are high, two or more eggs may be laid per pod.
There are four larval instar stages of the CSPW and each stage is white and grub-like in appearance ranging up to 5-6mm in length (refer to lower left photo). The first instar larva feeds on the cuticle on the outside of the pod while the second instar larva bores into the pod, feeding on the developing seeds. A single larva consumes about 5 canola seeds. The mature larva chews a small, circular exit hole from which it drops to the soil surface and pupation takes place in the soil within an earthen cell. Approximately 10 days later, the new adult emerges to feed on maturing canola pods. Later in the season these new adults migrate to overwintering sites beyond the field.
Monitoring: Begin sampling when the crop first enters the bud stage and continue through the flowering. Sweep net samples should be taken at ten locations within the field with ten 180° sweeps per location. Count the number of weevils at each location. Samples should be taken in the field perimeter as well as throughout the field. Adults will invade fields from the margins and if infestations are high in the borders, application of an insecticide to the field margins may be effective in reducing the population to levels below which economic injury will occur. An insecticide application is recommended when three to four weevils per sweep are collected and has been shown to be the most effective when canola is in the 10 to 20% bloom stage (2-4 days after flowering starts). Consider making insecticide applications late in the dayto reduce the impact on pollinators. Whenever possible, provide advanced warning of intended insecticide applications to commercial beekeepers operating in the vicinity to help protect foraging pollinators. High numbers of adults in the fall may indicate the potential for economic infestations the following spring.
Lygus bugs (Lygus spp.) – The economic threshold for Lygus in canola is applied at late flower and early pod stages. Biological and monitoring information can be linked by clicking here or you can access Manitoban, or Albertan fact sheets or the Prairie Pest Monitoring Network’s monitoring protocol.
Adult L. lineolaris (5-6 mm long) (photo: AAFC-Saskatoon).
Fifth instar lygus bug nymph (3-4 mm long) (photo: AAFC-Saskatoon).
Damage: Lygus bugs have piercing-sucking mouthparts and physically damage the plant by puncturing the tissue and sucking plant juices. The plants also react to the toxic saliva that the insects inject when they feed. Lygus bug infestations can cause alfalfa to have short stem internodes, excessive branching, and small, distorted leaves. They feed on buds and blossoms and cause them to drop. They also puncture seed pods and feed on the developing seeds causing them to turn brown and shrivel.
Begin monitoring canola when it bolts and continue until seeds within the pods are firm. Since adults can move into canola from alfalfa, check lygus bug numbers in canola when nearby alfalfa crops are cut.
Sample the crop for lygus bugs on a sunny day when the temperature is above 20°C and the crop canopy is dry. With a standard insect net (38 cm diameter), take ten 180° sweeps. Count the number of lygus bugs in the net.
Repeat the sampling in another 14 locations. Samples can be taken along or near the field margins. Calculate the cumulative total number of lygus bugs and then consult the sequential sampling chart (Figure C). If the total number is below the lower threshold line, no treatment is needed. If the total is below the upper threshold line, take more samples. If the total is on or above the upper threshold line, calculate the average number of lygus bugs per 10-sweep sample and consult the economic threshold table.
Sequential sampling for lygus bugs at late flowering stage in canola.
The economic threshold for lygus bugs in canola covers the end of the flowering (Table 1) and the early pod ripening stages (Table 2). Once the seeds have ripened to yellow or brown, the cost of controlling lygus bugs may exceed the damage they will cause prior to harvest, so insecticide application is not warranted.
Table 1. Economic thresholds for lygus bugs in canola at late flowering and early pod stages (Wise and Lamb 1998).
1 Canola crop stage estimated using Harper and Berkenkamp 1975).
2 Economic thresholds are based on an assumed loss of 0.1235 bu/ac per lygus bug caught in 10 sweeps (Wise and Lamb. 1998. The Canadian Entomologist. 130: 825-836).
Table 2. Economic thresholds for lygus bugs in canola at early pod stage (Wise and Lamb 1998).
3 Economic thresholds are based on an assumed loss of 0.0882 bu/ac per lygus bug caught in 10 sweeps (Wise and Lamb. 1998. The Canadian Entomologist. 130: 825-836).
Time of Swathing – The Canola Council of Canada created a guide to help growers estimate swathing time in canola. A screen shot of the downloadable guide has been included below for reference.
Harvest Sample Program – The Canadian Grain Commission is ready and willing to grade grain samples harvested in 2015. This is a FREE opportunity for growers to gain unofficial insight into the quality of their grain and to obtain valuable dockage information and details associated with damage or quality issues. More information on the Harvest Sample Program is available at the Canadian Grain Commission’s website or growers can register online to receive a kit to submit their grain. The following screen shot of the CGC webpage offers more details.
Provincial Insect Pest Updates – The following provincial websites have their pest updates posted so click the links to access their reports:
● Manitoba’s Insect and Disease Report (August 4, 2015) featuring lygus bugs and a reminder for the Fall grasshopper monitoring plus how it supports the 2016 grasshopper forecast map.
● Saskatchewan’s Insect Update (July 23, 2015) featuring descriptions of causes of white heads in wheat.
● Alberta’s Insect Update (Call of the Land audio report of August 6, 2015) featuring lygus bugs, aphids in cereals and diamondback moths.
Insect of the Week – Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide (2015) by Hugh Philip is a new publication from Agriculture and Agri-Food Canada. This growing season we will post an “Insect of the Week” in the form of short excerpts from the field guide. This week features the Beet webworm.
Crop Reports – The following provincial websites now have their Crop Reports posted so click the links to find their weekly updates:
West Nile Virus Risk –The regions most advanced in degree-day accumulations for Culex tarsalis, the vector for West Nile Virus, are shown in the map below. Areas highlighted in red on the map below will have accumulated sufficient heat for C. tarsalis to fly.
The Public Health Agency of Canada posts information related to West Nile Virus in Canada and their website is located here. The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance. As of this week, nine birds in Ontario and five birds in Quebec tested positive for West Nile-related deaths (click here to view the report).
As of August 9, 2015, adult C. tarsalis are predicted to be in flight throughout much of the prairies – apply DEET if you are active outdoors within areas highlighted red, rose or pink in the map below!! Areas highlighted orange should be prepared with DEET!
Questions or problems accessing the contents of this Weekly Update? Please e-mail either Dr. Owen Olfert or Jennifer Otani. Past and present “Weekly Updates” are very kindly posted to the Western Forum website by webmaster, Dr. Kelly Turkington. Please click here to link to that webpage.
Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide – The NEW Field Guide to Support Integrated Pest Management (IPM) in Field and Forage Crops is NOW available for download from www.publications.gc.ca. Two downloadable (~8 MB) versions of the complete field guide are available as either a ‘Regular’ (i.e., best for printing: English, French) or ‘Enhanced’ (i.e., best for viewing electronically with active internal and external hyperlinks: English-enhanced, French-enhanced).
Wind trajectories Related to Diamondback Moth (DBM) and Aster Leafhopper Introductions – Completed for the season. Please refer to earlier Weekly Updates for details related to backward and forward trajectories associated with air parcels moving over western Canadian locations.
Flea Beetles (Chrysomelidae: Phyllotreta species) – Helpful images produced by Dr. Julie Soroka (AAFC-Saskatoon) exemplifying percent of cotyledon leaf area consumed by flea beetles are posted at Canola Watch.
Canola Insect Scouting Chart – The Canola Insect Scouting Chart has been updated with hyperlinks now directing growers to downloadable pages from the NEW Field Guide!
Alfalfa Weevil (Hypera postica) – Alfalfa growers are encouraged to check the Alfalfa Weevil Fact Sheet prepared by Dr. Julie Soroka (AAFC-Saskatoon).
Cabbage root maggot (Delia spp.) – A summary of root maggot biology, research, and pest management recommendations for canola production was published by Soroka and Dosdall (2011). Remember there are no registered insecticides for root maggot control in canola.
This week’s Insect of the Week is the beet webworm (Loxostege sticticalis (Linnaeus)) (from the new Field Crop and Forage Pests and their Natural Enemies in Western Canada – Identification and Management Field Guide – download links available on the Insect of the Week page).
This week’s Insect of the Week is the red turnip beetle (Entomoscelis americana Brown) (from the new Field Crop and Forage Pests and their Natural Enemies in Western Canada – Identification and Management Field Guide – download links available on the Insect of the Week page).
This week’s Insect of the Week is the alfalfa looper(Autographa californica Speyer) (from the new Field Crop and Forage Pests and their Natural Enemies in Western Canada – Identification and Management Field Guide – download links available on the Insect of the Week page).
This week’s Insect of the Week is the Bertha armyworm(Mamestra configurata (Walker)) (from the new Field Crop and Forage Pests and their Natural Enemies in Western Canada – Identification and Management Field Guide – download links available on the Insect of the Week page).
This week’s Insect of the Week is a two-fer: aphids and their natural mortal enemies, ladybird beetles (from the new Field Crop and Forage Pests and their Natural Enemies in Western Canada – Identification and Management Field Guide – download links available on the Insect of the Week page).
The blister beetle (Lytta nuttalli Say and Epicauta spp.) is this week’s Insect of the Week (from the new Field Crop and Forage Pests and their Natural Enemies in Western Canada – Identification and Management Field Guide – download links available on the Insect of the Week page).
The grasshopper (Packard, clearwinged, migratory and two-striped) is this week’s Insect of the Week (from the new Field Crop and Forage Pests and their Natural Enemies in Western Canada – Identification and Management Field Guide – download links available on the Insect of the Week page).
The cabbage seedpod weevil (Ceutorhynchus obstrictus (Marsham)) is this week’s Insect of the Week (from the new Field Crop and Forage Pests and their Natural Enemies in Western Canada – Identification and Management Field Guide – download links available on the Insect of the Week page).
The lygus bug (Lygus spp.) is this week’s Insect of the Week (from the new Field Crop and Forage Pests and their Natural Enemies in Western Canada – Identification and Management Field Guide).
The swede midge (Contarinia nasturtii (Keiffer)) is this week’s Insect of the Week (from the new Field Crop and Forage Pests and their Natural Enemies in Western Canada – Identification and Management Field Guide).
Field Crop and Forage Pests and their Natural Enemies in Western Canada: IDENTIFICATION AND MANAGEMENT FIELD GUIDE
Whether you’re a new or experienced producer, agrologist or field scout in Western Canada, “What’s ‘bugging’ this crop?” and “Does it need to be controlled?” are typical questions raised when scouting for pests in a field of grain, oilseed, pulse or forage.
This new, 152-page, full-colour field guide, now available online, is designed to help you make informed decisions in managing over 90 harmful pests of field and forage crops in Western Canada. Better decision making helps save time and effort and eliminates unnecessary pesticide applications to improve your bottom line. The guide also helps the reader identify many natural enemies that prey on or parasitize pest insects. Recognizing and fostering populations of natural enemies will enhance their role in keeping or reducing pest populations below economic levels.
FREE download from www.publications.gc.ca Click here to download English, French
What you’ll find inside:
Description of over 90 economic pests and 30+ natural enemy species or species groups:
diagnostic characteristics
life cycle
damage
monitoring/scouting techniques
economic threshold
control options: biological, cultural and chemical
Large full-colour photos depicting various life stages of featured pests and natural enemies
Overview of Integrated Pest Management (IPM) strategies
Natural enemy and pest relationships
Book Description
Author: Hugh Philip, 2015
Published by: Agriculture and Agri-Food Canada, Saskatoon, SK [with funding from the Pest Management Centre’s Pesticide Risk Reduction Program]
Pages: 152
Downloadable formats: pdf and pdf-enhanced [features internal hyperlinks allowing the reader to quickly jump to referenced pages]
Languages: Available in English and French
French title: Guide d’identification des ravageurs des grandes cultures et des cultures fourragères et de leurs ennemis naturels et mesures de lutte applicables à l’Ouest canadien
This week’s Insect of the Week highlights pea leaf weevil (from the new Field Crop and Forage Pests and their Natural Enemies in Western Canada – Identification and Management Field Guide).
In follow-up to Scott Hartley’s observations, this week’s Insect of the Week highlights diamondback moth (from the new Field Crop and Forage Pests and their Natural Enemies in Western Canada – Identification and Management Field Guide). See also Insect of the Week from May 11 for flea beetle description, scouting and management options.
See this week’s Insect of the Week for descriptions and pictures of the aster and potato leafhoppers (Macrosteles quadrilineatus and Empoasca fabae) from the new Field Crop and Forage Pests and their Natural Enemies in Western Canada – Identification and Management Field Guide
See this week’s Insect of the Week for descriptions and pictures of the crucifer and striped flea beetles (Phyllotreta cruciferae and P. striolata) from the new Field Crop and Forage Pests and their Natural Enemies in Western Canada – Identification and Management Field Guide
