Biological Control Agents

What is Biological Control?

Biological control, commonly referred to as “bio-control”, is a method of suppressing invasive plants by reuniting them with their natural enemies, such as insects and plant diseases. The goal of bio-control is to suppress weed infestations to a more environmentally and economically acceptable level. Bio-control will not eradicate weed infestations.

How do Biological Control Agents Reduce the Impact of Invasive Plants?

Biological control agents…
  • Destroy vital plant tissues and functions
  • Increase stress on weeds thereby reducing their competitive ability
  • Reduce seed production

Successful biological control is generally achieved by using a variety of agents that attack different parts of the weed throughout its lifecycle.

Why Use Biological Control Over Other Control Methods?

Chemical and physical control measures can effectively reduce invasive plant infestations in many situations. However, these options can also be impractical, labour intensive, and costly. When infestations are large and dense or occur in sensitive habitats, biological control is often the only suitable option for long-term, effective control.

Is Biological Control the Right Option for Your Property?

Check the list below to see if the invasive plant problem on your land meets the criteria for a potential release site:

  • Sizeable weed infestation, one acre or more;
  • Will not be treated with herbicide;
  • Soil disturbance, such as vehicular traffic or cultivation is minimal; and
  • Agents are available for your target species

It will be necessary to have a weed specialist conduct a site visit to determine whether this option is suitable for your property and to identify if biological control agents are already present. Regular monitoring will be required to determine insect establishment and success.

For further information on biocontrol options, contact OASISS at 1-250-404-0115 or



Cyphocleonus Achates - a weevil that feeds on knapweed foliage.
Photo Credit: L. Scott

Biocontrol Resources

Brochure Biological control agents Insects that Attack Invasive Plants in the Okanagan-Similkameen
Link to PDF

A brochure that outlines biological control agents that attack invasive plants in the Okanagan-Similkameen, prepared by OASISS. 


Photo Credit: Government of B.C.

 Biocontrol Process in British Columbia
Link to PDF

A document prepared by MFLNRORD that outlines the biocontrol process in British Columbia.

Invasive Plants

Photo Credit: Government of BC

 Invasive Plants with Biocontrol in BC
MFLNRORD provides a list of invasive plant species in B.C. that have biocontrol agents.