Biological Control

Biological control, or biocontrol, is the use of living organisms to control weeds or pests. Most often insects are the agents used for invasive plant control.

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The goal of weed biocontrol is to increase herbivory on exotic invasive plants releasing native plants from the invasive plant’s completive edge. This is done by releasing biocontrol agents, usually insects, into weed populations.

Biocontrol agents are regulated by the USDA, Animal Plant Health Inspection Service (APHIS) and must go through a rigorous scientific evaluation prior to introduction. The process from discovery to release takes many years. Agents who attack native species will not make the cut. However, agents which prove to be extremely selective and only seek the weed of concern may be considered for biocontrol release. Most often, successful agents will not completely eradicate their targets population, but instead their population will rise and fall as the targets population rises and falls.

Release of non-indigenous organisms doesn’t come without some level of risk. Wyoming Weed and Pest Districts utilizes biocontrol as part of our integrated management planning. This means we only consider the use of biocontrol insects for weed management of widespread weed populations, populations where other management options are not appropriate, or populations in extremely challenging terrain. The goal of biocontrol is not eradication, but rather to even the playing field.

The Wyoming Biological Control Steering Committee has a strong history of supporting the research and development of new biocontrol agents for the state. Current projects supported include the research for potential agents for the control of whitetop, dyer’s woad, Russian olive, Russian knapweed, yellow and dalmatian toadflax, perennial pepperweed, houndstongue, and oxeye daisy.

For more information about Wyoming biocontrol, please contact your local county Weed and Pest Supervisor (see District directory), or the Chairman of the Wyoming Biological Control Steering Committee, Aaron Foster at 307-332-1052 or