When done in the right situations, biocontrol can be an excellent and effective addition to an Integrated Pest Management (IPM) program. Strathcona County is hoping to add biocontrol to our current invasive plant management programming. Some situations are ideal for biocontrol, whereas others remain better suited for mechanical or chemical control.

Situations where biocontrol may be your best option need the following features:

• the population of weeds is high enough to support a classical biocontrol agent,
• the goal of weed management is suppression, NOT eradication,
• the weed species has been present for years,
• resource needs (e.g. monitoring, risk of weed spread to more sensitive areas, etc.) are low, and
• there is a suitable biocontrol agent available, with information from local experts and research regarding the agent and the target weed species.

In cases where the weed population is small, new, and/or eradication is the goal, biocontrol is not a suitable option.

Biocontrol often takes several years to see an impact, and requires a living organism, so if the population does not establish, they will need to be reintroduced, or an alternative control method considered.

We have projects involving three different species.

Yellow Toadflax Stem Mining Weevils (Mecinus janthinus) have established throughout the City of Edmonton. They have previously been released at the Centennial Park Wetland Replacement Site in Sherwood Park, and are established there. We also are planning to release at a site in Shadow Ridge Estates, assuming they are not already present.

The municipal reserve in Portas Gardens has leafy spurge on a south facing slope on a difficult to access spot near a wetland – ideal to try some biocontrol! Leafy Spurge Beetles (Euphorbia esula) are scheduled to be released in 2024 at this site.

We plan to trial sheep at Centennial Park as well. They will visit the site 2-3 times this year. We are seeing if grazing controls or suppresses the current growth of Canada thistle, yellow toadflax and common tansy.

There are some biocontrol agents available for public release. The Alberta Invasive Species Council has a biocontrol release program and you can purchase agents through them. There are other companies throughout Canada and the USA, although importing agents can be difficult and time consuming.

As per Alberta’s Weed Control Act, landowners and occupants are still required to control or contain noxious and prohibited noxious weed species. If you have been issued a weed notice, you will still have to control the listed species as per the weed notice. If you are interested in using a legitimate biocontrol plan in response to your weed notice or friendly letter, please contact an Invasive Plant Specialist with Strathcona County prior to implementation.

Dandelions are not considered a regulated weed. They can be an eyesore, but act as an important early-season pollinator, and can be grazed by livestock. Therefore, dandelion control is not considered as a focus for biocontrol efforts.

Herbicide is an essential part of Strathcona County’s current invasive plant management programming and is often the more fiscally responsible method to control regulated species across a large area.

Only Pest Management Regulatory Agency (PMRA) approved herbicides are applied by trained and certified staff. We focus on spot spraying regulated species and controlling vegetation along roadsides to maintain sightlines.

If you do not want herbicide applied to the roadsides adjacent to your property, you can sign up for the Landowner Option Program here.

Classical biocontrol goes through years of rigorous testing to ensure that the biocontrol agents will not have negative impacts on non-target species. There are only five cases known worldwide where a non-target plant species was attacked where none were predicted (out of hundreds of introductions). A classical biocontrol agent must be species specific – in order for it to be approved for release in Canada, it must be sufficiently proven that the agent cannot complete its lifecycle on any other plant and would actually rather die than eat any other plant species.

Unfortunately, we will not be focusing biocontrol efforts on mosquitoes. They are a natural part of the ecosystem, and populations will fluctuate with water levels and precipitation events. There are already many natural enemies of mosquitoes, including larger bugs, birds and bats. In fact, you can conduct your own conservation biocontrol efforts by encouraging the populations of those species in your own yards!

Rural ditches are County-owned rights-of-way. As a landowner, Strathcona County is responsible for preventing the spread of noxious and prohibited noxious weeds on County-owned land. This is necessary to protect natural areas, agricultural land and private landowners from the spread of invasive plants that can disrupt ecosystems, cause harm to humans and animals, or economically impact farmers.

Rural residents in Strathcona County who do not wish to have herbicide sprayed in the ditch next to their property can register with the County’s Landowner Option Program (LOP). Once enrolled in the LOP, landowners assume the responsibility of noxious weed, prohibited noxious weed and brush control. To learn more, or to take part in the program, please contact Planning and Development Services at 780-464-8080.

Spraying herbicide is one tool that the County uses, along with mowing and brushing, to manage the weeds and brush in the ditch. All products used are approved and regulated by Health Canada and applied by certified applicators.

For more information on the products used, please contact 780-417-7100.

We spray herbicide to treat weeds designated as noxious and prohibited noxious under the Alberta Weed Act. Trees and brush under two metres tall are also sprayed to prevent them from getting too close to the road. 

Depending on the location, some areas are broadcast sprayed, meaning equipment will spray herbicide to cover the entire ditch. Other areas are spot-sprayed, meaning County staff walk in the ditch and spray only certain plants by hand.

All properties registered as "no spray" within the Landowner Option Program are excluded from spraying.

The County sprays all roadsides south of Highway 16 annually using a combination of spot-spraying and broadcast spraying. 

The County broadcast sprays all the roadsides north of Highway 16 every other year on odd numbered years.

County land that is not part of annual spraying programs may be either spot-sprayed or broadcast sprayed, as required. 

Vegetation control on primary and secondary highways is the responsibility of Alberta Transportation. View a complete listing of primary and secondary highways in Strathcona County. 

If there are weed concerns in ditches along highways or railroads, Strathcona County will notify the proper authorities.