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Weed Busters

by Craig Flentie, Lewistown FO

 participants gather after collecting bugs

Participants divvy up the day's catch after a successful biological control agent (bug) gathering near Grass Range.
BLM photo

weed-eating bugs 

A cup of bugs on its way to a new weed patch. These mecinus attack both the leaves and root system of their host plant (dalmation toadflax).
BLM photo

Note: Although this article focuses on the Lewistown Field Office, similar weed control techniques are used in BLM offices across Montana/Dakotas.
Noxious weeds present a continuously robust problem for public land managers. Every year established weed patches try to expand and new patches seem to appear as quickly as bills in the mail.    

Noxious weeds spread easily -- some by natural patterns such as wind and/or flowing water, and others after their seeds are transported by human, livestock and wildlife movement. Weed seeds can also hitch a ride on the wheels or undercarriage of a vehicle carelessly driven through a patch before falling off to start another infestation. 

Controlling or eliminating noxious weeds is not easy.

For those BLMers involved with noxious weed management, the importance of being creative and making a dollar go as far as possible has never been greater.  Noxious weeds are a national concern on public lands and over the years, the weed infestations have grown. On average, the BLM’s budget to address noxious weeds has not grown as fast as the collective weed patch.

To respond to this continuous tug-of-war, the Lewistown Field Office has developed an innovative, efficient, and cost effective weed control program that relies heavily on the assistance of livestock grazing permittees.

Through cooperative agreements, livestock grazing permittees agree to complete the labor portion of weed control on the BLM land they graze. The BLM agrees to provide herbicide or biological control agents, recommend rates of application, conduct inventories, monitor infested sites, and in some cases, provide equipment assistance.

This cooperative effort has evolved into an extremely cost effective program in the endless war on noxious weeds. The Lewistown FO is extremely fortunate to work with a group of grazing permittees who have demonstrated an exemplary level of awareness and dedication to noxious weed control.    

“The effectiveness of our weed control program depends on this cooperation and we applaud our permittees for their efforts,” offered Lowell Hassler, a natural resource specialist in the Lewistown FO who manages the cooperative agreement program. 

Other Weapons in the War on Weeds

The Lewistown FO also uses a variety of other methods in the effort to keep noxious weeds at bay. 

 “Our noxious weed management program has grown to include several biological control insectaries which serve as distribution centers for private and public land throughout the western United States. These insectaries include various species of agents (bugs) in a wide range of stages, varying from experimental to distribution. The weed species targeted by our biological control efforts include leafy spurge, spotted knapweed, Russian knapweed, Canada thistle, Dalmation toadflax, poison hemlock, salt cedar, hound’s-tongue and hoary cress (whitetop),” according to Hassler. 

Each year the BLM hosts a bug gathering day at one or several of these insectaries.  BLM staffers and landowners will venture into the insectary, armed with fine mesh nets and cups to hold their catch. On a calm day, it’s common to net multiple thousands of bugs to be transported in a Styrofoam cup (best used with a lid) until they are released on a new site. These gathers are popular events among landowners interested in using biological control on their property.    

The Lewistown FO has also entered into cooperative agreements for weed control utilizing domestic sheep grazing. This program is very effective, but is limited to geographical areas with concentrated weed infestations and adequate water supply for large bands of sheep. 

In addition, the Lewistown FO targets specific weed infestations at specific locations around the state for chemical applications by sponsoring cooperative weed control days with other agencies and public entities. These efforts are generally geared toward a fun, educational, and productive days in the battle against noxious weeds.  

The BLM also works cooperatively with the county weed departments in the nine counties that make up the central Montana zone. 

 “We’ve found that it takes a full tool box to make progress or just stay even with the rate of spread we’ve seen with noxious weeds. Each of these methods has its place on the landscape, but our cooperative agreements with grazing permittees are certainly the most effective means we’ve found for keeping noxious weeds at a manageable level,” Hassler said.                             



Last updated: 06-28-2012