Biological controls in Archuleta County


By Ethan Proud | PREVIEW Columnist

Biological controls (biocontrols) are insect and pathogens introduced from an invasive species’ native range to naturally control them in their invaded range. 

Researchers make determinations of likely candidates through observation in the weeds’ home range and then study it for about a decade. The potential biocontrol candidate is rigorously tested to determine if it will damage and reduce the success of its target species and that it will not jump to a new host species. Biocontrol agents that will adapt to a new host are not cleared for release. 

Registered biocontrol agents are a great way to manage invasive species populations without using herbicides or a lot of manpower to physically remove plant species from a site. Biocontrols do not eradicate a weed species, but instead reduce its success in order to level the playing field for native plant species. 

Ideal sites for biocontrols are ones that: are difficult to reach, will receive minimal or planned disturbance, and have a management goal of containment and suppression. Biocontrols can be added to either a mechanical or chemical control plan.

In Archuleta County we are using biocontrols to manage musk thistle, Canada thistle, leafy spurge, Russian knapweed, yellow toadflax and field bindweed. 

We have established nursery sites for Canada thistle and Russian knapweed, and may have nursery sites for leafy spurge and musk thistle in the near future. We discovered a nursery site for field bindweed at Navajo State Park and coordinated a biocontrol collection event in 2021. 

Yellow toadflax is our most recent addition of biocontrol agents, and we are hoping to establish populations before determining if any of our sites would be good candidates for a nursery.

Species that do not have a local nursery site can be ordered from the Colorado Department of Agriculture Palisade Insectary, while species that do have a local nursery site can be requested from the Archuleta County Weed and Pest Department. Both agencies offer biocontrols on the basis of seasonal availability and not all orders can be accommodated in a given year.

Currently Archuleta County does not have a program for diffuse and spotted knapweed biocontrols, though the Insectary does offer these agents. If you are interested in utilizing biocontrols to control diffuse or spotted knapweed (or any other weed mentioned in this article) please reach out to the Archuleta County Weed and Pest Department, we would be very interested in working with you.

Classes canceled
and postponed

The Preserving the Harvest class scheduled for Sept. 16 has been canceled.

The Seed Saving class set for Sept. 23 has been postponed.

Look on the Extension Facebook page for additional information. 

CPR and first aid classes

CPR and first aid certification classes are offered every other month by the CSU Extension office, generally on the second Monday and Wednesday of each month from 6 to 10 p.m. The cost for the classes is $80 for combined CPR/first aid and $55 for CPR, first aid or recertification. Call the Extension office at (970) 264-5931 to register. Check out the online option on our website