Fall Good Time to Manage Some Pasture Weeds

Musk Thistle
Musk Thistle
(NDSU)

Fall is the best time to control some notorious weeds in pastures and other grasslands, according to North Dakota State University Extension specialists.

“Leafy spurge and invasive thistles can be challenging to control in pasture and grasslands due to their extensive root systems,” says Miranda Meehan, Extension livestock environmental stewardship specialist. “In the fall, plants begin to allocate energy to their root systems. As a result, fall herbicide treatment maximizes injury to the root system.”

Here is advice on dealing with some of the worst weeds.

Leafy Spurge

“Proper timing of herbicide applications is essential for good leafy spurge control,” says Extension rangeland management specialist Kevin Sedivec.

In the fall, leafy spurge is most susceptible to Tordon (picloram), dicamba (Banvel and other trade names), Facet L (quinclorac), Facet L + Overdrive and Method (aminocyclopyrachlor). Fall-applied Plateau (imazapic) provides better long-term control and causes less grass injury than spring or summer treatments.

The combination of Tordon plus Overdrive also will improve leafy spurge control compared with Tordon used alone. Overdrive contains dicamba plus difluenzopyr, which is an anti-auxin compound that often improves broadleaf weed control when applied with auxinlike herbicides such as Tordon, dicamba and 2,4-D.

To achieve the greatest control, the treatment must be applied at the appropriate stage of development. Tordon, dicamba and Facet L should be applied when the plant has 4 to 12 inches of regrowth. However, Method is most effective when applied at the rosette stage. Overdrive should be applied prior to a killing frost.

Leafy spurge control must be considered a long-term management program, the specialists say. Research at NDSU has shown that more of the root system is killed when a combination of control methods is used, compared with any method used alone.

Thistles

Thistles tend to invade overgrazed or otherwise disturbed pastures, rangeland, roadsides and waste areas. Fall is the ideal time to treat many on the noxious thistle list, including Canada thistle, musk thistle and bull thistle. If you are unsure of what thistle you have, refer to the NDSU Extension publication “The Thistles of North Dakota."

Control of Canada thistle is usually greater when treatment is applied in the fall to plants in the rosette form. Herbicides that control Canada thistle in noncropland include products that contain clopyralid (various), Tordon (picloram), dicamba (various), dicamba plus diflufenzopyr (Overdrive), Method (aminocyclopyrachlor) and Milestone (aminopyralid).

Fall is the preferred time for applying herbicides to biennial thistles, such as musk thistle and bull thistle. This allows for application at the rosette stage, when the plants are most susceptible to herbicides.

Herbicides should be applied as late as possible in the fall, but prior to a killing frost, to allow for maximum seedling emergence and rosette size. Seedlings that emerge after spraying will remain vegetative until the following spring and can be treated then.

Biennial thistles can be controlled effectively with Milestone (aminopyralid), Stinger, Transline or Curtail (clopyralid), Tordon (picloram), Method (aminocyclopyrachlor), or dicamba (various) or dicamba plus diflufenzopyr (Overdrive).

Consult NDSU Extension Service publication W253, “North Dakota Weed Control Guide” for the latest recommendations for noxious weed control with herbicides. Grazing restrictions vary with herbicide and application rate, so read the label carefully before using any product.

 

Latest News

Star Ranch Angus Brand Refresh

Carrying branded programs such as Tyson's Star Ranch Angus beef has benefits for both retailers and consumers. Shoppers still associate branded programs with better quality, better value and more consistency.

Embracing the Positives in Sustainable Cattle Production

Cattlemen are the original climate heroes, preserving natural resources, while producing safe, affordable and abundant protein. Speakers at NCBA's Winter Reboot discussed how cattle production contributes to society.

Commodity Group Execs Say Biden's Top Trade Pick Tai Knows Agriculture

While trade is not a headline of the Biden Administration in the first 100 days, it’s not stopping Katherine Tai from making her voice heard. Tai is now waiting full confirmation vote to put her ideas to work.

BLM Rescinds Hammond's Grazing Permits

In another installment in the years-long saga of the Hammond Ranch, the Interior Department on Friday rescinded grazing permits that had been restored under the Trump administration.

CAB Insider: Quality Carcass Spreads Turn Up Early

The two weeks in the middle of the month marked by extreme weather and insufficient fed cattle to harvest-space put a cap on cattle prices as packers found themselves well-supplied.

Victor Ranch Receives Oklahoma Leopold Conservation Award

The Victor Ranch has been selected as the recipient of the 2020 Oklahoma Leopold Conservation Award®, which recognizes land owners who inspire with their dedication to land, water and wildlife habitat resources.