Southern Interior Weed Management Committee

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The Thompson-Nicola Regional District (TNRD) currently offers a number of invasive plant management programs with rebates to landowners living within the Region. Click here to learn more about them.

NEW TNRD NOXIOUS WEED CONTROL PROGRAM FORMS NOW AVAILABLE TO DOWNLOAD:

50% treatment cost share application

herbicide rebate application

new invaders 100% rebate application

herbicide treatment day sheet

list of licensed applicators

biological control program

Biological control agents are organisms such as insects, nematodes, fungi or viruses, that can be used to control and reduce weed populations. They are usually natural enemies of the target weeds, originating from Europe and Asia.


Agopeta zoegana (pupa stage)	Agopeta zoegana (adult moth stage)	Mecinus janthinus	Cyphocleonus achates

Biological control is suitable for large, dense infestations where other management strategies are neither cost-effective nor environmentally desirable. A good example of such an area in the Thompson-Nicola Region would be knapweed infestations in open grasslands. The agent usually works at weakening the target plant's seed production by feeding on the seed heads, or by eating or inhabiting other parts of the plant (i.e. root systems). Biological control will not generally eliminate the weed problem, and its results are usually seen over time.

The SIWMC has been working for the Thompson Nicola Regional District to offer biological control agents to private landowners within the TNRD free of charge. Biological control is one strategy that is used to combat the spread of some noxious weed species.

how to look for bio agents
note: insect availability is weather dependent

		Hounds Tongue (Mogulones cruciger) • The weevil is approx. 2-3mm long. It is a blackish brown color with a white cross on its back. • Look for feeding damage on the leaves and at the base of the leaves where they join the stem. • These weevils are hard to find in person, they drop off the plant and pretend they’re dead as soon as they see you coming. • These weevils are available in May
		Dalmation Toadflax (Mecinus janthinus) • Look for feeding damage on the stem and foliage of the plant. • Look for the weevil itself. Black weevil is approx. 3-4mm long. • These weevils are out in May-June
		Spotted/Diffuse Knapweed (Larinus minutus) • The Larinus weevil affects the seed head of the plant. • The Weevil ranges in color from black to brown to green to tan and is approx. 4-5 mm long • On the old plants, look for a bullet hole in the top of the seed head (that is where the weevil emerged) • These weevils are available most of the summer, June-August
		Spotted/Diffuse Knapweed (Cyphocleonus achates) • The Cyphocleonus Achates weevil affects the root of the plant. • The weevil is approx. 20mm long and is grey and white in color (blends in with the plant) • In spring and early summer, pull up a root—the larvae will be burrowed down the center of the root system. • There can be more than one in each root. • These weevils are available July-August
		Spotted/Diffuse Knapweed (Agapeta zoegana) • A. zoegana is a small bright yellow moth, 10 mm in length, with brown wing bands. • The adults may be found resting vertically on the knapweed stems or under the leaves. They have the appearance of dead or dying knapweed leaves. • In the spring and early summer, look at the root of a knapweed plant—Agapeta girdles the outside of the root system • The larvae of Agapeta is long and skinny with a brown head.
		Leafy Spurge (Apthona nigriscutus) • The Apthona beetles are approximately 3-3.5 mm long and are a shiny brown or brownish with a black dot on their back behind their thorax • The beetles are out from late July-August

Agents are available in the TNRD for the following invasive plant species:

Bio agent	Typical agent availability*
Diffuse Knapweed Agapeta zoegana Cyphocleonus achates Larinus spp.	Mid June to late July August Mid June to mid July
Spotted Knapweed Agapeta zoegana Cyphocleonus achates Larinus spp.	Mid June to late July August Mid June to mid July
Leafy Spurge Apthona cyparissiae Apthona nigriscutis	Mid June to mid August Mid June to mid August
Dalmation Toadflax Mecinus janthinus Rhinusa spp.	Mid March to end of May Mid May to end of June / Mid July to September
Hound's Tongue Mogulones cruciger	April to end of May / August to mid September
Thistles Rhinocyllus conicus Larinus planus	July to August Mid June to Mid July

*NOTE: Hound's Tongue and Thistle agents are dependent on agent availability in the Southern Interior Region of British Columbia. Typical availability of adult agents is dependent on the bio agent species and subject to change as a result of seasonal factors.

As a result of the success of the biological control program over the past several years, some of these biological agents are now well established and widespread throughout the Thompson-Nicola Region. For more information about the TNRD's biological control program, or to fill out a request for bio control check out the TNRD’s biological control program or contact the SIWMC Coordinator .

If you are currently on our list of candidates for receiving biological control agents, please be sure to keep your personal contact information up to date. Please contact us if any of this information has changed.

In 1994, the BC Ministry of Forests and Range published a field guide for biological control agents in British Columbia. This guide is designed to help resource managers in British Columbia identify weeds and select suitable biological control agents for those weeds. Biological control offers stable, long-term solutions to weed problems across the province.

To view and download a PDF version of the Field Guide to the Biological Control of Weeds in British Columbia, click here.