Weed Control

Biological Controls (Weevils) | Canada Thistle Stem-Gall Flies | CHAP | Fenceline Program | Weed Identification


Biological Controls

Canada Thistle Stem Mining Weevil

If you’re looking for an option to control Canada thistle besides using herbicides, handpicking or mowing, this biological control agent may be right for you.

The Canada thistle Stem Mining Weevil (Hadroplontus litura) was introduced from Europe to Canada in 1965 and to the USA in the early 1970’s to feed on Canada thistle. The weevil restricts its feeding to this weed and a few close relatives. Weevil feeding may allow a variety of other micro-organisms to enter the thistle stem, with adverse consequences for the thistle: field studies in Montana indicated that underground parts of stems are much more subject to winter kill if the above ground stem is attacked by weevils during the growing season.

West Central Forage Association has been working with local producers on the release of these weevils for years. Sites, where weevils have been released, have generally shown decreased stand vigour and patches thin out over time. In 2012, 50 dishes (each containing 105 weevils) were brought up from Montana for producers in the West Central Region who were interested in the purchase and release them in thistle patches. Added to this, were 58 dishes for a regional trial set up by the Agricultural Research and Extension Council of Alberta. Yellowhead County also releases these weevils along the edges of rivers, lakes and streams, and in or near right-of-ways where herbicide application is prohibited.

If you are interested in purchasing some Weevils please contact:
West Central Forage Association
1-780-727-4447
conservationag@westcentralforage.com

Field after the introduction of Weevils.

Weevil Information Sheet

Weevil Summary Sheet with Before & After Images

Canada Thistle Stem-Gall Flies

The Canada thistle stem-gall fly is a biological control agent for use in controlling Canada thistle. In 2017 WCFA began facilitating the distribution of these agents to producers throughout the province, bringing them in from Montana.

The stem-gall fly attacks the stem of the thistle plant, boring in and causing the plant to form gall tissue. Females lay their eggs on the apical meristem (tip) of developing shoots in the early summer, and larvae burrow into the shoots. Larval feeding triggers gall formation, which stresses the plant. The gall becomes a nutrient sink, directing nutrients away from the plant’s normal metabolic & reproductive functions, lowering normal plant function and reproduction. Abnormally developed flower heads frequently occur above the gall, resulting in fewer flowers and lowered seed production. Galls vary in size, depending on the number of larvae present within. Galls may range in size from small (marble) to large (walnut/plum), containing anywhere from three or four larvae to upwards of 25 larvae. The flies overwinter in the gall as mature larvae and emerge as adults in the spring (around June) as the gall tissue deteriorates.

Stem-gall flies are typically delivered in mid-June each year, with orders needing to be placed ahead of time.

Stem-Gall Flies Fact Sheet

C.H.A.P. (Custom Herbicide Application Program)

Yellowhead County Agricultural Services Board has approved a Custom Herbicide Application Program to control Noxious and/or Prohibited Noxious weeds on private property.

This program will help Yellowhead County residents control weeds where the options of hiring a contractor and renting or purchasing spray equipment are not feasible.  The program will be run on a first-come, first-serve basis during the spraying season and as weather permits.

The herbicide will be applied onto the private land, not exceeding 20 acres.  Sites will be pre-inspected to determine if the property qualifies for the program and what equipment and herbicide will be necessary.

The landowner will be asked to sign a release allowing the County access to the property and permission to use herbicide as agreed upon by the landowner and Yellowhead County Agricultural Services Staff.  Pricing will depend on the area sprayed and the herbicide used. Upon completion, landowners will receive an invoice for the work performed.

Yellowhead County has added CHAP to enhance services to the residents of Yellowhead County in addition to the existing Roadside Vegetation Management Plan and Weed Inspection Program.

If you would like more information on this or any Agricultural Services Programs or to register for CHAP please contact the Agricultural Services Department in Wildwood at 1-800-814-3935.

Fence Line Program

The Fence Line Program helps to control Noxious and/or Prohibited Noxious weeds and encroaching brush along fence lines on private property adjacent to Yellowhead County roads and right-of-ways.

The Fence Line Program will allow Yellowhead County-owned vehicles and equipment to enter the private land and apply herbicide from the fence line to the County Right of Way. This program will help control weeds and brush without the chances of overspray onto private land where sensitive crops or trees may be located.

The herbicide will only be applied to County-owned land and not onto the private land; exceptions are made for fields used for agricultural purposes where landowners may choose to have the four-foot strip from the fence line to their crop sprayed that larger spray equipment or cultivators tend to miss. Sites will be pre-inspected to determine if the property qualifies for the program and what equipment and herbicide will be necessary.

The landowner will be asked to sign a release allowing the County access to the property and permission to use herbicide as agreed upon by the landowner and Yellowhead County Agricultural Services Staff. This program will be completed on a first come first served basis and at no charge to landowners.

Yellowhead County has added the Fence Line Program to enhance services to the residents of Yellowhead County in addition to the existing Roadside Vegetation Management Plan.

If you would like more information on this or any Agricultural Services Programs or to register for the Fence Line Program please contact the Agricultural Services Department in Wildwood at 1 800-814-3935.

Weed Identification

Yellowhead County’s Agricultural Services Department is able to assist residents with weed or plant identification.

Here are some tips to remember that will assist staff in the identification process:

If bringing in a live plant sample for us to identify please:

Try to dig up or pull out the roots along with the rest of the plant. Roots are a very important identifying feature.Put the plant in a cup or pot with some water to keep it from wilting. Some plants wilt very quickly making it harder to see some of the identifying features on the leaves, stems, and flowers.

Try pulling a plant sample that’s the most mature or better yet in the flowering stage.

If you are taking pictures of a plant sample for us to identify please:

  • Take at least 4 to 5 pictures of different parts of the plant. Take a picture that encompasses the entire plant in the frame, then take one of the stem and leaves, take one of the flower, flower buds, or seed head. Finally, if it’s possible pull the plant out of the ground and gently knock the soil off to expose the roots for a picture.
  • Make sure the pictures are clear! A lot of the pictures we get are very blurry or the focus is off the plant and on the grass or trees behind it. To get a clear picture keep your camera a little further away from the plant, its easier for us to zoom in on a part of the plant we need more detail on then it is for us to look at a blurry close up of the plant.
  • Try to keep the sun to your back when taking the pictures. If the sun is behind the plant it can sometimes wash out the colour of the plant or make it blurry and harder to see fine details.
  • If you want to pull the plant and take the pictures indoors with the plant laid out on a table that works too, just make to take the pictures as soon as you pull the plant to avoid wilting.

A great resource with facts sheets on weeds and other invasive species is the Alberta Invasive Species Council
https://abinvasives.ca/

Invasive Species Fact Sheets

https://abinvasives.ca/category/invasive-species/fact-sheets/