Biological Control of Weeds

Last Modified: May 28, 2024

A PPQ 526 permit is required for the importation, interstate movement and environmental release of most invertebrate herbivores that feed upon or infest non-native weeds (weeds introduced into areas where the co-evolved herbivores do not occur). 

Permits must be obtained before the importation or interstate movement and must specify the species to be moved as well as the State where the release or research will occur. If weed biocontrol agents for release are being obtained from a commercial or public source, the provider may have such a permit for release in your state, otherwise you will need to submit a PPQ 526 application.

Apply for a Permit

When applying for a permit to release, you will need to provide:

  • The scientific name(s) (Genus and species) of each species you wish to receive;
  • The name and location of the supplier;
  • The target weed(s);
  • The identity and source of any plant material that will accompany each species;
  • Other information that may be needed by APHIS

Redistribution across State lines requires additional permit(s). Movement and receipt of microbial biocontrol organisms may have additional requirements. If you plan to import weed biocontrol organisms you will most likely be required to receive the organisms into an inspected containment facility.

What is weed biocontrol and where do the biocontrol agents come from?

Classical biological control of weeds is a weed control method where exotic natural enemies from the places where the exotic weed originated are used to reduce weed infestations. The practice of weed biological control in the United States began in the 1940s and has resulted in some spectacular successes in the suppression of the targeted weed.

Today, and since about 1960, there has been a group of experts who advise APHIS on the decision to release a new non-indigenous weed biological control agent into the environment.

Researchers who wish to propose the first time environmental release of a new weed biological control species will need to become familiar with the requirements and procedures for submitting such a proposal.

APHIS considers the advice of the TAG-BCAW and other information before deciding to permit the release of weed biocontrol organisms new to the United States, and also requires specific environmental compliance and other procedures prior to permitting.