TETRASTICHUS JULIS

The cereal leaf beetle larvae you see in wheat fields may be full of this week’s Insect of the Week, Tetrastichus julis. This parasitoid wasp is an important natural enemy of cereal leaf beetle. Adult T. julis lay their eggs inside cereal leaf beetle larvae, leaving about five eggs to consume the beetle from the inside out. Adult parasitoids feed on nectar and aphid honeydew.  

A Tetrastichus julis female in the process of parasitizing a cereal leaf beetle larva, sitting on a wheat leaf with cereal leaf beetle feeding damage. Picture credit: Emily Lemke and Karen Shamash, AAFC-Lethbridge.

Mature T. julis larvae overwinter in infested cereal leaf beetle cocoons and emerge in spring to lay more eggs in cereal leaf beetle larvae. 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 (en français).  

AAFC researchers have assisted T. julis in establishing and spreading to help control cereal leaf beetle populations in the Canadian prairies! Reducing the use of insecticides (if possible), leaving refuge areas, and reducing tillage can all help protect populations of this valuable parasitoid in areas where they are already established in a field.  

Biological information related to T. julis and cereal leaf beetle in field crops is available online. For more information, visit the cereal leaf beetle page from 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).  

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)




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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


Weekly Update – Cereal leaf beetle predictions

Cereal leaf beetle (Oulema melanopus) – Based on last week’s warm weather, our bioclimate model predicted rapid development of cereal leaf beetle (CLB) populations.


As of May 15, 2016, the CLB model indicated that oviposition is well underway, though this week’s development was slower than the previous week. Model output predicted that egg populations should be peaking this week in both Alberta and Saskatchewan and next week at Swan River  MB. Larval populations are predicted to peak in mid-June in southern Alberta and Saskatchewan and one week later at Swan River MB locations.


Predicted dates of peak emergence of CLB eggs and larvae:






The following model outputs have been updated this week and reflect the predicted stages of CLB present in fields in relation to its parasitoid, Tetrastichus julis




Fact sheets for CLB are published by the province of Alberta and by the Prairie Pest Monitoring Network. Also access the Oulema melanopus page from the new “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide”.

Weekly Update – Cereal leaf beetle predictions

Cereal leaf beetle (Oulema melanopus) – Based on last week’s warm weather, our bioclimate model predicted rapid development of cereal leaf beetle (CLB) populations.


As of May 8, 2016, model indicated that oviposition is well underway and that larvae should be appearing across southern Alberta and a week later in southern Saskatchewan. Larval populations are predicted to peak in mid-June in southern Alberta and one to two weeks later at the Saskatchewan and Manitoba locations.




Predicted dates of peak emergence of CLB eggs and larvae:



Output suggests that it’s parasitoid, Tetrastichus julis, should be emerging during the period when CLB eggs are most abundant. The model run for Swan River MB showed potential symmetry for both species, though phenologies would be two weeks later than for southern Alberta.





 



Fact sheets for CLB are published by the province of Alberta and by the Prairie Pest Monitoring Network. Also access the Oulema melanopus page from the new “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide”.