Tag: Parasitoids

Aphids in field crops

Aphid populations can quickly increase at this point in the season and particularly when growing conditions are warm and dry. Access the Provincial Insect Pest Report for Wk12 to remain alert to areas and crops suffering from aphid pest pressure.

Figure 1. Pea aphid adults (each 3-4 mm long) and nymph. Photo: M. Dolinski.

Biological and monitoring information (including tips for scouting and economic thresholds) related to aphids in field crops is posted by:
• Manitoba Agriculture (aphids on cereals, aphids on flax, soybean aphid, aphids on peas)
• Saskatchewan Pulse Growers (aphids in pulse crops or access the PDF copy)
• Saskatchewan Flax Development Commission
• Manitoba Pulse and Soybean Growers (soybean aphids: identification, scouting and management or access the PDF copy)
• The Canola Council of Canada’s “Canola Encyclopedia” section on aphids
• or check your provincial commodity group’s insect pest webpages for more detailed information.

Alternatively, several aphid pest species are described in the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (2018) and is accessible as a free downloadable PDF in either English or French on our Field Guides page. PDF copies of the individual pages have been linked below to access quickly:
• Corn leaf aphid or Rhopalosiphum maidis (Fitch)
• English grain aphid or Sitobion (Macrosiphum) avenae (Fabricius)
• Oat-birdcherry aphid or Rhopalosiphum padi (Linnaeus)
• Pea aphid or Acyrthosiphon pisum (Harris)
• Potato aphid or Macrosiphum euphorbiae (Thomas)
• Soybean aphid or Aphis glycines (Matsumura)
• Turnip aphid or Lipaphis erysimi (Kaltenbach)
• Sugar beet root aphid or Pemphigus betae Doane
• Russian wheat aphid or Diuraphis noxia (Mordvilko)

Over the years, both the Weekly Updates and Insect of the Week have included aphid-related information but also important natural enemy details to support in-field scouting. Review the list below so pest and beneficial insects can be distinguished readily when scouting fields:
• Aphidius wasp (Insect of the Week; 2015 Wk15)
• Aphids in canola (Insect of the Week; 2016 Wk13)
• Aphids in cereals (Insect of the Week; 2017 Wk09)
• Cereal aphid manager APP (Weekly Update; 2021 Wk07) that presently is available only for iOS
• Ladybird larva vs. lacewing larva (Insect of the Week; 2019 Wk18)
• Ladybird beetles and mummies (Weekly Update; 2020 Wk15)
• Lygus bug nymphs vs. aphids (Insect of the Week; 2019 Wk16)
• Hoverflies vs. bees vs. yellow jacket wasps (Insect of the Week; 2019 Wk19)
• Pea aphids: a persistent problem for legume growers (Insect of the Week; 2021 Wk12)
• Soybean aphids and aphid annihilating allies (Insect of the Week; 2022 Wk07)
• Syrphid flies (Insect of the Week; 2015 Wk16)

Aphids in field crops

Aphid populations can quickly increase at this point in the season and particularly when growing conditions are warm and dry. Over the years, both the Weekly Updates and Insect of the Week included aphid-related information so here’s a list of these items to access when scouting fields:

• Aphidius wasp (Insect of the Week; 2015 Wk15)
• Aphids in canola (Insect of the Week; 2016 Wk13)
• Aphids in cereals (Insect of the Week; 2017 Wk09)
• Cereal aphid manager APP (Weekly Update; 2021 Wk07) that presently is available only for iOS
• Ladybird larva vs. lacewing larva (Insect of the Week; 2019 Wk18)
• Ladybird beetles and mummies (Weekly Update; 2020 Wk15)
• Lygus bug nymphs vs. aphids (Insect of the Week; 2019 Wk16)
• Hoverflies vs. bees vs. yellow jacket wasps (Insect of the Week; 2019 Wk19)
• Pea aphids: a persistent problem for legume growers (Insect of the Week; 2021 Wk12)
• Soybean aphids and aphid annihilating allies (Insect of the Week; 2022 Wk07)
• Syrphid flies (Insect of the Week; 2015 Wk16)

Wheat midge

Although the PPMN is unable to model and predict wheat midge development as in previous years, accumulated precipitation levels during May and June provide guidance in terms of in-field scouting. Access the Provincial Insect Pest Report for Wk09 for updates for this economic insect pest.

Important – the accumulated precipitation levels over past 60 days (May 5 to July 3, 2024) were mapped in Figure 1 and ranged from 60 to >250 mm across the prairies, well beyond the 45 mm threshold that facilitates larvae to exit their cocoons to pupate in the soil then emerge. Areas in Figure 1 receiving substantial rainfall this spring need to plan to scout for wheat midge now as adults typically emerge and seek wheat in early July.

Figure 1. 60 day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 5 -July 3, 2024.

Remember – the rate of development and timing of adult midge emergence varies at the field level and can only be verified through in-field scouting. Midge flight coinciding with the beginning of anthesis is a crucial point when in-field counts of wheat midge on plants are carefully compared to the economic thresholds.

Producers opting to grow cultivars susceptible to wheat midge need to be mindful that any historically elevated density of wheat midge occurring over the past one or even possibly six years across the prairies that also has received substantial rainfall since May of 2024, warrants in-field monitoring now. Review the past wheat midge maps here in relation to your fields THEN compare the historical densities to areas of high precipitation in Figure 1.

In-Field Monitoring: When scouting wheat fields, pay attention to the synchrony between flying midge and anthesis.  In-field monitoring for wheat midge should be carried out in the evening (preferably after 8:30 pm or later) when the female midges are most active. On warm (at least 15 ºC), calm evenings, the midge can be observed in the field, laying their eggs on the wheat heads (Fig. 3). Midge populations can be estimated by counting the number of adults present on 4 or 5 wheat heads. Inspect the field daily in at least 3 or 4 locations during the evening.

Figure 3. Wheat midge (Sitodiplosis mosellana) laying their eggs on a wheat head. Photo: AAFC-Beav-S. Dufton and A. Jorgensen.
Figure 4. Macroglenes penetrans, a parasitoid wasp that attacks wheat midge, measures only ~2 mm long.  Photo: AAFC-Beav-S. Dufton.

REMEMBER that in-field counts of wheat midge per head remain the basis of the economic threshold decision.  Also remember that the parasitoid, Macroglenes penetrans (Fig. 4), is actively searching for wheat midge at the same time.  Preserve this parasitoid whenever possible and remember insecticide control options for wheat midge also kill these beneficial insects who help reduce midge populations.

Economic Thresholds for Wheat Midge:
a) To maintain optimum No. 1 grade: 1 adult midge per 8 to 10 wheat heads during the susceptible stage.
b) To maintain yield only: 1 adult midge per 4 to 5 heads. At this level of infestation, wheat yields will be reduced by approximately 15% if the midge is not controlled.
Inspect the developing kernels for the presence of larvae and larval damage.

Albertans… please refer to this week’s Provincial Insect Pest Report Links to link to count reports of wheat midge for 2024.

Wheat midge was featured as the Insect of the Week in 2023 (for Wk08). Be sure to also review wheat midge and its doppelganger, the lauxanid fly, featured as the Insect of the Week in 2019 (for Wk11) – find descriptions and photos to help with in-field scouting!  Additionally, the differences between midges and parasitoid wasps were featured as the Insect of the Week in 2019 (for Wk12).  Remember – not all flying insects are mosquitoes nor are they pests! Many are important parasitoid wasps that regulate insect pest species in our field crops OR pollinators that perform valuable ecosystem services!

Information related to wheat midge biology and monitoring can be accessed by linking to your provincial fact sheet (Saskatchewan Ministry of Agriculture or Alberta Agriculture & Irrigation).  Alberta Agriculture & Irrigation has a YouTube video describing in-field monitoring for wheat midge.  

Additional information can be accessed by reviewing the Wheat midge pages extracted from the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide” (2018) accessible as a free downloadable PDF in either English or French on our new Field Guides page.

Wheat midge

Although the PPMN is unable to model and predict wheat midge development as in previous years, accumulated precipitation levels during May and June provide guidance in terms of in-field scouting. Elliott et al. (2009) reported that wheat midge emergence was delayed or erratic if rainfall did not exceed 20-30 mm during May. Olfert et al. (2016) ran model simulations to demonstrate how rainfall impacts wheat midge population density. The Olfert et al. (2020) model indicated that dry conditions may result in: (a) Delayed adult emergence and oviposition, and (b) Reduced numbers of adults and eggs.

Important – the accumulated precipitation levels over past 60 days (May 5 to July 3, 2024) were mapped in Figure 1 and ranged from 60 to >250 mm across the prairies, well beyond the 45 mm threshold that facilitates larvae to exit their cocoons to pupate in the soil then emerge. Areas in Figure 1 receiving substantial rainfall this spring need to plan to scout for wheat midge now as adults typically emerge and seek wheat in early July.

Figure 1. 60 day cumulative rainfall (mm) observed across the Canadian prairies for the period of May 5 -July 3, 2024.

Remember – the rate of development and timing of adult midge emergence varies at the field level and can only be verified through in-field scouting. Midge flight coinciding with the beginning of anthesis is a crucial point when in-field counts of wheat midge on plants are carefully compared to the economic thresholds.

Producers opting to grow cultivars susceptible to wheat midge need to be mindful that any historically elevated density of wheat midge occurring over the past one or even possibly six years across the prairies that also has received substantial rainfall since May of 2024, warrants in-field monitoring now. Review the past wheat midge maps here in relation to your fields THEN compare the historical densities to areas of high precipitation in Figure 1.

In-Field Monitoring: When scouting wheat fields, pay attention to the synchrony between flying midge and anthesis.  In-field monitoring for wheat midge should be carried out in the evening (preferably after 8:30 pm or later) when the female midges are most active. On warm (at least 15 ºC), calm evenings, the midge can be observed in the field, laying their eggs on the wheat heads (Fig. 3). Midge populations can be estimated by counting the number of adults present on 4 or 5 wheat heads. Inspect the field daily in at least 3 or 4 locations during the evening.

Figure 3. Wheat midge (Sitodiplosis mosellana) laying their eggs on a wheat head. Photo: AAFC-Beav-S. Dufton and A. Jorgensen.
Figure 4. Macroglenes penetrans, a parasitoid wasp that attacks wheat midge, measures only ~2 mm long.  Photo: AAFC-Beav-S. Dufton.

REMEMBER that in-field counts of wheat midge per head remain the basis of the economic threshold decision.  Also remember that the parasitoid, Macroglenes penetrans (Fig. 4), is actively searching for wheat midge at the same time.  Preserve this parasitoid whenever possible and remember insecticide control options for wheat midge also kill these beneficial insects who help reduce midge populations.

Economic Thresholds for Wheat Midge:
a) To maintain optimum No. 1 grade: 1 adult midge per 8 to 10 wheat heads during the susceptible stage.
b) To maintain yield only: 1 adult midge per 4 to 5 heads. At this level of infestation, wheat yields will be reduced by approximately 15% if the midge is not controlled.
Inspect the developing kernels for the presence of larvae and larval damage.

Albertans… please refer to this week’s Provincial Insect Pest Report Links to link to count reports of wheat midge for 2024.

Wheat midge was featured as the Insect of the Week in 2023 (for Wk08). Be sure to also review wheat midge and its doppelganger, the lauxanid fly, featured as the Insect of the Week in 2019 (for Wk11) – find descriptions and photos to help with in-field scouting!  Additionally, the differences between midges and parasitoid wasps were featured as the Insect of the Week in 2019 (for Wk12).  Remember – not all flying insects are mosquitoes nor are they pests! Many are important parasitoid wasps that regulate insect pest species in our field crops OR pollinators that perform valuable ecosystem services!

Information related to wheat midge biology and monitoring can be accessed by linking to your provincial fact sheet (Saskatchewan Ministry of Agriculture or Alberta Agriculture & Irrigation).  Alberta Agriculture & Irrigation has a YouTube video describing in-field monitoring for wheat midge.  

Additional information can be accessed by reviewing the Wheat midge pages extracted from the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide” (2018) accessible as a free downloadable PDF in either English or French on our new Field Guides page.

Field heroes

The Field Heroes campaign continues to raise awareness of the role of beneficial insects in western Canadian crops.

Field Heroes resources include:

  1. Real Agriculture went live in 2024 with Season 5 of the Pest and Predators podcast series!
    • NEW Episode 30 – Farmer feedback: Insect pest management practices  Haley Catton and Emma Stephens (Agriculture and Agri-Food Canada-Lethbridge) and Shaun Haney (RealAg). Published online May 29, 2024.
    • Episode 29 – The ecology of fear  Maya Evenden (University of Alberta) and Shaun Haney (RealAg). Published online May 14, 2024.
    • Episode 28 – Research roundup: Lesser clover leaf weevil  Jeremy Irvine (University of Saskatchewan) and Shaun Haney (RealAg). Published online May 1, 2024.
    • Episode 27 – Armoured tanks: Beetles in battle  Tyler Wist (Agriculture and Agri-Food Canada-Saskatoon) and Shaun Haney (RealAg). Published online April 17, 2024.
    • Episode 26 – Invasive species awareness: Knowing what to look for and how to report it  Meghan Vankosky (Agriculture and Agri-Food Canada-Saskatoon), James Tansey (Saskatchewan Ministry of Agriculture), John Gavloski (Manitoba Agriculture), and Shaun Haney (RealAg). Published online April 2, 2024.
    • Episode 25 – 20 years of canola surveying and counting!  Jennifer Otani (Agriculture and Agri-Food Canada-Beaverlodge) and Shaun Haney (RealAg). Published online March 19, 2024.
    • Review SEASON 4 of the Pest and Predators podcasts (2023)
    • Review SEASON 3 of the Pest and Predators podcasts (2022)
    • Review SEASON 2 of the Pest and Predators podcasts (2021)
    • Review SEASON 1 of the Pest and Predators podcasts (2020)
  2. The Pests and Predators Field Guide (2021) is filled with helpful images for quick insect identification and plenty of tips to manage the pests AND natural enemies in your fields.
  3. Crop Scouting Guides (2021) specific to cereals, oilseeds, or pulses.
  4. Scouting Guides (2022) for aphids, cutworms, diamondback moth larvae, or bertha armyworms.

Follow @FieldHeroes!

Parasitoids of Wheat Stem Sawfly

Bracon cephi and Bracon lissogaster are the primary parasitoids that attack wheat stem sawfly and help to regulate wheat stem sawfly populations in North America. These closely related parasitoid species are described as idiobiont ectoparasitoids. The parasitoid larva, after hatching from an egg laid on the surface of the wheat stem sawfly larva, consume the entire host except for the host’s head capsule and exoskeleton. Both Bracon species complete their development and pupate inside the wheat stem. Their pupae are generally found inside the exoskeleton or beside the remnants of their consumed wheat stem sawfly host. There are two generations of B. cephi and B. lissogaster per year.  The first generation completes its lifecycle then exits the wheat stem to locate a new host to parasitize.  The second generation overwinters within the wheat stem. 

Adult Bracon cephi parasitoid, pictured inside a vial (hence the artistic effect!) by Dylan Sjolie, AAFC-Saskatoon.

Bracon cephi and B. lissogaster are similar in appearance. The wasps are typically 2-15 mm long and 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 parasitoid wasps have long antennae and two pairs of transparent wings. Females have a noticeable ovipositor protruding from the end of the abdomen. 

Parasitoid population dynamics and efficacy are influenced by crop management practices. Parasitoids can be conserved by increasing the height of stubble when harvesting and reducing insecticide applications in grass ditches where natural enemies of the wheat stem sawfly are abundant. 

For more pictures and information about the natural enemies of the wheat stem sawfly, check out our past Insect of the Week post about Bracon cephi!

PARASITOIDS OF DIAMONDBACK MOTH

This week, our insects of the week are the natural enemies of diamondback moth found on the Prairies! Four important parasitoids attack this pest: Diadegma insulare, Diadromus subtilicornis, Microplitis plutellae, and Trichogramma praetiosum.

A pupa of the parasitoid Diadegma insulare inside its cocoon. Picture credit: Andrea Brauner, AAFC.

Some of these species (like Diadegma insulare) follow diamondback moth on its yearly migration from the southern United States and some (like Micropletis plutellae) overwinter in Canada and can help with early-season control. These small, dark colored wasps occasionally completely control diamondback moth outbreaks in Canada! 

Parasitoids of diamondback moth. On the left: Diadegma insulare. On the right: Microplitis plutellae. Both pictures taken by Amanda Jorgensen, AAFC-Beaverlodge Research Farm.

The four parasitoid species attack during different stages of the diamondback moth lifecycle. Diadegma and Micropletis parasitoids attack larval diamondback moth. Trichogramma and Diadromus species attack the prepupal and pupal stages.

A female Diadromus parasitoid preparing to parasitize a diamondback moth pupa. Picture credit: Andrea Brauner, AAFC.

There is a long list of other wasp species that have been found to parasitize diamondback moth larvae to a lesser extent. Hoverfly larvae, yellowjacket wasps, lacewings, plant bugs, pirate bugs, beetles, spiders and birds also prey on diamondback moth larvae. 

Biological and monitoring information related to diamondback moths in field crops can be found on our Monitoring page as well as on provincial Agriculture Ministry pages (Manitoba, Saskatchewan and Alberta). For more information, visit the diamondback moth page in the Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Management field guide. (en français : 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). You can find more information about some of the parasitoids of diamondback moth on the field heroes website or learn about Braconid wasp life cycles here. 

CUTWORM KILLERS: ICHNEUMONIDS and TACHINIDS

While you’re out scouting for cutworms, tachinids flies and ichneumonid wasps are scouting for them too! We have two Insects of the Week this week and both are parasitoids of cutworm pests. Parasitoids complete part of their lifecycle inside another organism, in this case cutworms, eventually killing them.  

Adult tachinid flies are pale or dark brown in colour with long, bristly hairs covering their bodies. Females typically lay one to several eggs on a host. Upon hatching the larvae burrow into the host, develop inside, and then exit to pupate in the soil. Adult flies feed on flower nectar, honeydew from aphids, scale insects, and mealybugs. The tachinid, Athrycia cinerea (Coq.), is a parasitoid of the Bertha armyworm.  

An adult tachinid fly (Tachinia algens) reared from glassy cutworm. Photo credit: Shelby Dufton, AAFC-Beaverlodge Research Farm.

Ichneumonidae adults vary in size and colouration but all have a narrow waist, a long abdomen, and long antennae. Females have long ovipositors that they use to inject eggs into their hosts, including cutworm larvae. Adults eat nectar and aphid honeydew. Ichneumonid larvae (including Banchus flavescens) are parasitoids of Lepidoptera, Coleoptera, Diptera, Hymenoptera, and some spiders.  

An adult Ichneumonid parasitoid of the genus Banchus, reared from a dingy cutworm. Photo credit: Shelby Dufton, AAFC-Beaverlodge Research Farm.

For more information about these parasitoids, the other pests they control and other important crop and forage insects, see the Field Crop and Forage Pests and their Natural Enemies in Western Canada guide. The guide has helpful information about the life cycle of these and other parasitoids. The guide also has tips for conserving parasitoids and pictures to help with identification.

Field heroes

The Field Heroes campaign continues to raise awareness of the role of beneficial insects in western Canadian crops.

Two NEW Field Heroes resources for 2021 include:

  1. Real Agriculture went live in 2021 with Season 2 of the Pest and Predators podcast series!
    • NEW – Episode 11 – Free farm labour (June 15, 2021)
    • Episode 10 – Good bugs relocate for work (June 1, 2021)
    • Episode 9 – Secret agents in the stubble (May 18, 2021)
    • Episode 8 – Good vs pea leaf weEVIL (May 4, 2021)
    • Episode 7 – Powerful parasitoids: Better than fiction (April 20, 2021)
    • Recap of SEASON 1: Episode 1 – Do you know your field heroes? Episode 2 – An inside look at the Prairie Pest Monitoring Network. Episode 3 – How much can one wasp save you? Episode 4 – Eat and be eaten — grasshoppers as pests and food Episode 5 – Killer wasp has only one target — wheat stem sawfly Episode 6 – Plentiful parasitoids
  2. The NEW 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 for free to arm your in-field scouting efforts!

Access ALL the Field Heroes links here and be sure to follow @FieldHeroes!

Field heroes

The Field Heroes campaign continues to raise awareness of the role of beneficial insects in western Canadian crops.

Two NEW Field Heroes resources for 2021 include:

  1. The NEW 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 for free to arm your in-field scouting efforts!
  2. Real Agriculture went live in 2021 with Season 2 of the Pest and Predators podcast series!
    • NEW – Episode 10 – Good bugs relocate for work (June 1, 2021)
    • Episode 9 – Secret agents in the stubble (May 18, 2021)
    • Episode 8 – Good vs pea leaf weEVIL (May 4, 2021)
    • Episode 7 – Powerful parasitoids: Better than fiction (April 20, 2021)
    • Recap of SEASON 1: Episode 1 – Do you know your field heroes? Episode 2 – An inside look at the Prairie Pest Monitoring Network. Episode 3 – How much can one wasp save you? Episode 4 – Eat and be eaten — grasshoppers as pests and food Episode 5 – Killer wasp has only one target — wheat stem sawfly Episode 6 – Plentiful parasitoids

Access ALL the Field Heroes links here and be sure to follow @FieldHeroes!

Field heroes

The Field Heroes campaign continues to raise awareness of the role of beneficial insects in western Canadian crops. Check the recently updated Field Heroes website for scouting guides, downloadable posters, and videos. Learn about these important organisms at work in your fields!  

Two NEW Field Heroes resources for 2021 include:

  1. The NEW 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 for free to arm your in-field scouting efforts!
  2. Real Agriculture went live in 2021 with Season 2 of the Pest and Predators podcast series!
    • NEW – Episode 10 – Good bugs relocate for work (June 1, 2021)
    • Episode 9 – Secret agents in the stubble (May 18, 2021)
    • Episode 8 – Good vs pea leaf weEVIL (May 4, 2021)
    • Episode 7 – Powerful parasitoids: Better than fiction (April 20, 2021)
    • Recap of SEASON 1: Episode 1 – Do you know your field heroes? Episode 2 – An inside look at the Prairie Pest Monitoring Network. Episode 3 – How much can one wasp save you? Episode 4 – Eat and be eaten — grasshoppers as pests and food Episode 5 – Killer wasp has only one target — wheat stem sawfly Episode 6 – Plentiful parasitoids

Access ALL the Field Heroes links here and be sure to follow @FieldHeroes!

Field heroes

The Field Heroes campaign continues to raise awareness of the role of beneficial insects in western Canadian crops. Check the recently updated Field Heroes website for scouting guides, downloadable posters, and videos. Learn about these important organisms at work in your fields!  

Two important NEW resources for 2021 include:

  1. The NEW Pests and Predators Field Guide is filled with helpful images for quick insect indentification 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 for free to arm your in-field scouting efforts!

2. Real Agriculture went live in 2021 with Season 2 of the Pest and Predators podcast series!

• Access Episode 6 – Powerful parasitoids: Better than fiction (April 20, 2021)

• Access Episode 7 – Good vs pea leaf weEVIL (May 4, 2021)

• Recap of SEASON 1: Episode 1 – Do you know your field heroes? Episode 2 – An inside look at the Prairie Pest Monitoring Network. 3 – How much can one wasp save you? Episode 4 – Eat and be eaten — grasshoppers as pests and food Episode 5 – Killer wasp has only one target — wheat stem sawfly Episode 6 – Plentiful parasitoids

Access ALL the Field Heroes links here and be sure to follow @FieldHeroes!

Field heroes

The Field Heroes campaign continues to raise awareness of the role of beneficial insects in western Canadian crops. Check the recently updated Field Heroes website for scouting guides, downloadable posters, and videos. Learn about these important organisms at work in your fields!  

Real Agriculture went live in 2020 with a Pest and Predators podcast series!

• Access Episode 1 – Do you know your field heroes? Jennifer Otani (Agriculture and Agri-Food Canada-Beaverlodge) and Shaun Haney (RealAg). Published online May 12, 2020.

• Access Episode 2 – An inside look at the Prairie Pest Monitoring Network. Meghan Vankosky (Agriculture and Agri-Food Canada-Saskatoon) and Shaun Haney (RealAg). Published online May 26, 2020.

• Access Episode 3 – How much can one wasp save you? Haley Catton (Agriculture and Agri-Food Canada-Lethbridge) and Shaun Haney (RealAg). Published online June 9, 2020.

• Access Episode 4 – Eat and be eaten — grasshoppers as pests and food John Gavloski (Manitoba Agriculture and Resource Development) and Shaun Haney (RealAg). Published online June 23, 2020.

• Access Episode 5 – Killer wasp has only one target — wheat stem sawfly Scott Meers (Mayland Consulting) and Shaun Haney (RealAg). Published online July 7, 2020.

• Access Episode 6 – Plentiful parasitoids Tyler Wist ( Agriculture and Agri-Food Canada-Saskatoon) and Shaun Haney (RealAg). Published online July 21, 2020.

Access ALL the Field Heroes links here and be sure to follow @FieldHeroes!

Field heroes

The Field Heroes campaign continues to raise awareness of the role of beneficial insects in western Canadian crops. Check the recently updated Field Heroes website for scouting guides, downloadable posters, and videos. Learn about these important organisms at work in your fields!  

Real Agriculture went live in 2020 with a Pest and Predators podcast series!

• Access Episode 1 – Do you know your field heroes? Jennifer Otani (Agriculture and Agri-Food Canada-Beaverlodge) and Shaun Haney (RealAg). Published online May 12, 2020.

• Access Episode 2 – An inside look at the Prairie Pest Monitoring Network. Meghan Vankosky (Agriculture and Agri-Food Canada-Saskatoon) and Shaun Haney (RealAg). Published online May 26, 2020.

• Access Episode 3 – How much can one wasp save you? Haley Catton (Agriculture and Agri-Food Canada-Lethbridge) and Shaun Haney (RealAg). Published online June 9, 2020.

• Access Episode 4 – Eat and be eaten — grasshoppers as pests and food John Gavloski (Manitoba Agriculture and Resource Development) and Shaun Haney (RealAg). Published online June 23, 2020.

• Access Episode 5 – Killer wasp has only one target — wheat stem sawfly Scott Meers (Mayland Consulting) and Shaun Haney (RealAg). Published online July 7, 2020.

• Access Episode 6 – Plentiful parasitoids Tyler Wist ( Agriculture and Agri-Food Canada-Saskatoon) and Shaun Haney (RealAg). Published online July 21, 2020.

Access ALL the Field Heroes links here and be sure to follow @FieldHeroes!

Field heroes

The Field Heroes campaign continues to raise awareness of the role of beneficial insects in western Canadian crops. Check the recently updated Field Heroes website for scouting guides, downloadable posters, and videos. Learn about these important organisms at work in your fields!  

Real Agriculture went live in 2020 with a Pest and Predators podcast series!

• Access Episode 1 – Do you know your field heroes? Jennifer Otani (Agriculture and Agri-Food Canada-Beaverlodge) and Shaun Haney (RealAg). Published online May 12, 2020.

• Access Episode 2 – An inside look at the Prairie Pest Monitoring Network. Meghan Vankosky (Agriculture and Agri-Food Canada-Saskatoon) and Shaun Haney (RealAg). Published online May 26, 2020.

• Access Episode 3 – How much can one wasp save you? Haley Catton (Agriculture and Agri-Food Canada-Lethbridge) and Shaun Haney (RealAg). Published online June 9, 2020.

• Access Episode 4 – Eat and be eaten — grasshoppers as pests and food John Gavloski (Manitoba Agriculture and Resource Development) and Shaun Haney (RealAg). Published online June 23, 2020.

• Access Episode 5 – Killer wasp has only one target — wheat stem sawfly Scott Meers (Mayland Consulting) and Shaun Haney (RealAg). Published online July 7, 2020.

Access ALL the Field Heroes links here and be sure to follow @FieldHeroes!

Doppelgangers: midge vs. parasitoid

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.

Is that a midge or a parasitoid? Why does it matter?

Small insects (i.e., less than 5 mm) are difficult to identify, even for trained specialists and professional entomologists. Especially if they are alive, flying around. Or in a sweep net sample quickly assessed in the field. In the case of midge and small-bodied parasitoids, they can be easily mistaken for one another, but their roles in agriculture tend to be very different. 

Some of the most well-known prairie midge species are agricultural pests, such as the orange coloured wheat midge (Sitodiplosis mosellana), black-coloured Hessian fly (Mayetiola destructor), and alfalfa blotch leafminer (Agromyza frontella). Other midge species found on the prairies include biting midge like no-see-ums (Ceratopogonidae), black flies (Simuliidae), and non-biting midge (Chironomidae). Midge that are not considered agricultural pests may provide some ecosystem services (i.e., pollination), while other midge are disease vectors and are pests of medical and veterinary concern. 

A – Hessian fly – adult
Scott Bauer, USDA Agricultural Research Service, Bugwood.org
B – Swede midge – adult
Susan Ellis, USDA APHIS PPQ, Bugwood.org
C – Wheat midge – adult
Mike Dolinski, MikeDolinski@hotmail.com

Parasitoids are natural enemies of other insects. Thus, many parasitoids are important because they help control agricultural pest populations. Adult parasitoids lay eggs, usually singly, onto or into their host. The larvae that hatch from the eggs develop using the host as food, and eventually kill the host. An individual host usually provides enough food for just one parasitoid larva. For this reason, parasitoids species are rarely larger in size than their host species. On the prairies, important parasitoid families that may be mistaken for midge or other small, black insects include: Aphidiinae, Braconidae, Chalchididae, Encyrtidae, Eulophidae, Platygasteridae, Pteromalidae and Trichogrammididae. Sticky cards or sweep net samples may contain hundreds or thousands of small, black, winged insects. Many are probably parasitoids and not pests so look closely when scouting. A few key differences to watch out for include:

  • Parasitoids have two pairs of wings while midge have only one pair of wings     
  • Parasitoids are often shiny or metallic shades of black, blue, purple or green     
  • Midge may look hairy; parasitoids rarely look hairy.  
1 – Aphidiinae – adult (Aphidius avenaphis)
Tyler Wist, AAFC
2 – Braconid wasp – adult
Alberta Agriculture and Rural Development
3 – Chalcid wasp – adult (Phasgonophora sulcata)
Michael Gates, Encyclopedia of Live, EOL.org
4 – Tetrastichus julis – adult parasitizing a cereal leaf beetle larva
Swaroop Kher, University of Alberta/AAFC
5 – Ichneumonid – adult (Banchus flavescens)
John Gavloski, Manitoba Agriculture, Food and Rural Development
6 – Platygasterid – adult (Inostemma sp.)
Tyler Wist, AAFC
7 – Pteromalid – adult (Pteromalus puparum)
Koorosh McCormack, Natural History Museum: Hymenoptera Section, EOL.org
8 – Trichogrammid – adult (Trichogramma sp.) parasitizing an egg  
Jack Kelly Clark, University of California Statewide IPM Program

Specific information on these families of parasitoids and on the species of midge listed here can be found in 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.

Post contributed by Dr. Meghan Vankosky.

Insect of the Week – Natural Enemies of the wheat stem sawfly

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!

Bracon cephi (Gahan) (H. Goulet)

Insect of the Week – Natural enemies of the canola flower midge

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 (Contarinia brassicola, 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.

Gastrancistrus sp. (Hymenoptera: Pteromalidae)
(c) 2016 Boyd Mori, AAFC
Inostemma sp. (Hymenoptera: Platygastridae)
(c) 2016 Boyd Mori, AAFC

Submitted by Dr. Boyd Mori and Dr. Meghan Vankosky

Find out more about the natural enemies of the canola flower midge and more at the Insect of the Week page!

Insect of the Week – Natural enemies of pea aphids

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.

The many faces of the adult harlequin ladybeetle 
 (aka multicoloured Asian ladybeetle) (Photo: ©Entomart)
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.

Abundant parastioids in canola!

The cabbage seedpod weevil is a chronic pest of canola in southern Alberta and south western Saskatchewan; it has recently reached Manitoba as well. The pest is managed with insecticides, which are sprayed at early flower. This year, in some canola fields around Lethbridge AB, an abundant parasitoid wasp was noticed at the time when fields may be sprayed. The wasp was identified as Diolcogaster claritibia (Fig. 1; thanks to Vincent Hervet and Jose Fernandez for confirming identification).

The wasp is a parasitoid that attacks diamondback moth larvae and recently abundant in some fields in 2017. In some of the fields sampled, as many parasitoids as cabbage seedpod weevil (i.e., nearly one per sweep) were observed. In the fields sampled (i.e., around 10), cabbage seedpod weevils were below thresholds on average, though some spots may have been close to the threshold of 2-3 weevils per sweep.

The above observation emphasizes the value of beneficial arthropods like Diolcogaster claritibia.  It is important to recognize that foliar applications of insecticides kill beneficial insects like this small wasp (about 2 mm) which attacks and helps regulate pest populations of diamondback moth or other Lepidoptera, including cutworms and cabbage worms. Thus, think beneficials before you spray!

Figure 1.  Diolcagaster claritibia adult measuring ~2mm in length (Photo credit J. Fernandez, AAFC-Ottawa).

Learn more about beneficials by accessing Field Heroes and all the Blog’s Parasitoid posts.

Request for Cereal Leaf Beetle Larvae

Reminder – Researchers need your help – They are looking for LIVE cereal leaf beetle larvae from any field across the Canadian prairies in order to assess Tetrastichus julis parasitism rates.

If larvae are encountered in 2018, please carefully collect 20-30 of them and put them with some cereal leaves and a moist paper towel in a hard container (e.g. plastic yogurt container) with holes poked in the lid for air. Pack the parcel with ice packs, label with your name, date, crop type, and location, and send them to us.  Email or phone us for information on how to ship for free.

What’s in it for you? Learn if cereal leaf beetle is being controlled by natural enemies in your field. If you need T. julis, we may be able provide you with some.

Contact:
Dr. Haley Catton, Agriculture and Agri-Food Canada
5403 – 1 Ave S, Lethbridge, Alberta T1J 4B1
403-317-3404, haley.catton@agr.gc.ca

Request for Cereal Leaf Beetle Larvae

Researchers need your help – They are looking for LIVE cereal leaf beetle larvae from any field across the Canadian prairies in order to assess Tetrastichus julis parasitism rates.

If larvae are encountered in 2018, please carefully collect 20-30 of them and put them with some cereal leaves and a moist paper towel in a hard container (e.g. plastic yogurt container) with holes poked in the lid for air. Pack the parcel with ice packs, label with your name, date, crop type, and location, and send them to us.  Email or phone us for information on how to ship for free.

What’s in it for you? Learn if cereal leaf beetle is being controlled by natural enemies in your field. If you need T. julis, we may be able provide you with some.

Contact:
Dr. Haley Catton, Agriculture and Agri-Food Canada
5403 – 1 Ave S, Lethbridge, Alberta T1J 4B1
403-317-3404, haley.catton@agr.gc.ca

Insect of the Week – Tetrastichus julis

This week’s Insect of the Week is Tetrastichus julis. They are a parasitoid enemy of the cereal leaf beetle. Mature larvae overwinter in infested cereal leaf beetle cocoons and emerge in spring to lay more eggs in cereal leaf beetle larvae. Adults feed on nectar and aphid honeydew.



For more information on Tetrastichus julis, visit our Insect of the Week page.

Tetrastichus julis – adult parasitizing a cereal leaf beetle larva
(Swaroop Kher, University of Alberta/AAFC)




Follow @FieldHeroes to find out how natural enemies are working for you for FREE to protect your crops!


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

Insect of the Week – Aphidius parasitoid wasp

This week’s Insect of the Week is the Aphidius parasitoid wasp. Their hosts include over 40 species of aphids. Egg to adult development occurs inside the host. New adults chew a hole in the mummified aphid to exit and immediately search for new aphid hosts.

For more information on the Aphidius parasitoid wasp, see our Insect of the Week page.

Parasitized English grain aphid (Tyler Wist, AAFC)
Aphidiidae – adult (Aphidius avenaphis) (Tyler Wist, AAFC)

Follow @FieldHeroes to learn more about the natural enemies that are working for you for FREE to protect your crops!

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

AAFC posts new IPM video

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’s often 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 new video.

 
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.

Insect of the Week – Natural Predators

The importance of non-crop areas as habitat for beneficial insects



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 the Insect of the Week page] 
Natural enemies don’t just appear from nowhere – they rely on nearby
non-crop and (semi-)natural sites for shelter, food, overwintering sites and
alternate hosts for when crop pests are either not present or in low numbers.
How you manage these sites can have a huge impact on natural enemies’ capacity
to supress pests when you need them to. These same sites are also essential
habitats for pollinators, important for maximizing yield of non-cereal seed
crops (e.g. oil seed crop). A recent publication, ‘Agricultural practices that
promote crop pest suppression by natural predators’, describes the role of
non-crop areas and management practices to nurture natural enemy populations.
Go to the Insect of the Week page for download links for
this publication. There you will also find more information about natural
enemies, the pests they control and details about important crop and forage
pest insects by downloading the new Field Crop and Forage Pests and their
Natural Enemies in Western Canada – Identification and Management Field Guide.



Insect of the Week – Natural predators

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 the Insect of the Week page] 
Natural enemies don’t just appear from nowhere – they rely on nearby
non-crop and (semi-)natural sites for shelter, food, overwintering sites and
alternate hosts for when crop pests are either not present or in low numbers.
How you manage these sites can have a huge impact on natural enemies’ capacity
to supress pests when you need them to. These same sites are also essential
habitats for pollinators, important for maximizing yield of non-cereal seed
crops (e.g. oil seed crop). A recent publication, ‘Agricultural practices that
promote crop pest suppression by natural predators’, describes the role of
non-crop areas and management practices to nurture natural enemy populations.
Go to the Insect of the Week page for download links for
this publication. There you will also find more information about natural
enemies, the pests they control and details about important crop and forage
pest insects by downloading the new Field Crop and Forage Pests and their
Natural Enemies in Western Canada – Identification and Management Field Guide.



Insect of the Week – Trichomalus lucidus

Cabbage seedpod weevil parasitoids


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 the Insect 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

Weekly Update – Aphids in canola

If you encounter aphids in canola, know that it could be one of several species!  The following was kindly offered by Dr. Julie Soroka (Research Scientist Emeritus with AAFC-Saskatoon):


A small survey was conducted in canola in central Saskatchewan in 2014 and 2015 and a few fields were observed with aphids.  When found, over 90% of the aphid colonies were turnip aphid (Lipaphis erysimi).  Of the remainder, more of the generalist feeder, the green peach aphid (Myzus persicae), was found than cabbage aphid (Brevicoryne brassicae).  Interestingly, several of the aphid colonies were infested with the parasitic wasp, Dieretiella rapae!

Insect of the Week – Bertha armyworm parasitoids

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).

Ichneumonid – adult (Banchus flavescens). © John Gavloski, Manitoba Agriculture

Tachinid- adult. © Alberta Agriculture and Rural Development


Insect of the Week – Cotesia margeniventris

Cotesia margeniventris (parasitoid)

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

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


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

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


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


Insect of the Week – Aphidius wasp

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). 

(c) Tyler Wist, AAFC