Biological control or biocontrol is the use of natural enemies, such as insects or pathogens, to reduce the populations of non-native weeds and other pests to minimal and acceptable levels. These natural enemies also known as biocontrol agents are typically imported from areas where the weeds and other pests are native. Biocontrol agents undergo extensive testing prior to introduction in the environment. The goal is for the biocontrol agents keep the impact these unwanted weeds and other pests to a minimal and acceptable level.

There are many advantages associated with biocontrol programs including:

  • Low costs;
  • Self-sustaining, long-term control;
  • Ability to reach areas that are difficult to control by other control methods, such as deep draws, river banks or sensitive areas;
  • Highly selective and easy to handle.


There are also some disadvantages.  New biocontrol agents should be allowed a minimum of 3-5 years to establish following introduction into an environment.  Biocontrol also works best when weeds and other pest populations are widespread; small populations would be best controlled by using another control method.

Biocontrol can often be used in conjunction with other control methods; this is called Integrated Pest Management (IPM). For more information on identifying and controlling noxious weeds in ND using IPM, check out the publication “Identification and Control of Invasive and Troublesome Weeds in North Dakota”

Importation, interstate movement and environmental release of biocontrol agents requires a permit from the USDA-APHIS-PPQ. For more information on PPQ 526 permits visit the USDA-APHIS-PPQ webpage.



John Mortenson
Plant Protection Specialist