By Emily Spiler, Columbia Shuswap Invasive Species Society

Invasive Species and Biocontrol — an alternative method to herbicides or manual removal?

What is Biocontrol?

Biological weed control, also known as biocontrol, is a method of managing invasive species by exposing them to a natural enemy (most commonly insects).

When new plants are introduced, the predators, pests, or diseases that act as control agents are not brought with them. Without those natural enemies to keep them in check, sometimes these new weeds become invasive, quickly spreading and out-competing our native or agricultural plants.

Biocontrol aims to recreate this natural balance by using weed-specific insects that attack the noxious weed. The main goal is to reduce the weed population to environmentally and economically acceptable levels.

 How is a biocontrol agent chosen?

There are a series of actions that must take place before selecting a biocontrol agent. Long-term studies are conducted to ensure that the insect will only feed upon the targeted weed.

The initial biocontrol release is made under controlled conditions, and the Ministry of Forests Lands and Natural Resource Operations (MFLNRO) continues to monitor and evaluate before redistribution around the province.

A field of spotted knapweed before biocontrol Cyphocleonus achates.
A field of spotted knapweed before biocontrol Cyphocleonus aches. Year 1993
The positive effects of biocontrol. Year 2000.
The positive effects of biocontrol on the same field in the year 2000.

The province of BC has used biocontrol methods dating back to 1951, and they have proven to be successful. Biocontrol agents have already been used on a number of noxious weeds located around the province including leafy spurge, dalmation toadflax, spotted knapweed, and tansy ragwort.

The Future of Biocontrol

Invasive species management can be challenging and costly, therefore multiple options are considered for Integrated Pest Management.

Biocontrol is often a cost-effective and eco-friendly alternative for long term control of established species. In British Columbia, the use of biocontrol will continue to play an important role in integrated pest management programs.

For more information, visit the Ministry of Forests website at:

The Columbia Shuswap Invasive Species Society (CSISS) is a non-profit organization dedicated to the prevention, management and reduction of invasive species in the Columbia Shuswap Regional District. CSISS is thankful for the generous support of the Columbia Basin Trust, the Columbia Shuswap Regional District, the Ministry of Forests, Lands and Natural Resource Operations, and the Ministry of Transportation and Infrastructure.


Emily is a co-op student from the University of Waterloo and is completing her degree in Geography and Environmental Management. She has previously done placements with Ontario’s Ministry of Environment and Waterloo’s Ecohydrology Research Group. In her spare time, Emily can be found exploring and learning about BC and spending time with her family in Salmon Arm.