Weed Dept  

Noxious Weed Projects

The Weed Department is involved in many weed control projects each year. From dozens of private landowner jobs to several large scale public land projects the department is committed to controlling noxious weeds wherever they may grow. Showcase Projects — Rights-of-wayMatt WarnerPrivate LandLeafy Spurge

Uintah County Weed Department is required by law to control noxious vegetation on its properties the same as required of each citizen. Our goal is to provide aesthetically pleasing and safe travel corridors for the citizens and visitors of Uintah County. Below are some examples of excellent roadside weed control involving very difficult to control weeds.

EXAMPLE 1a — This area southwest of Randlett is heavily infested with Russian knapweed. In July 2007 the Weed Department applied Milestone herbicide @ 7 oz./Ac + S90 surfactant during full bloom.

Russian knapweed along a county road

EXAMPLE 1b — The same area in June 2008 shows excellent control, over 95%, of the roadside infestation of Russian knapweed. Grasses have grown in and the area continues to be relatively clean of knapweed due to regular herbicide applications each year.

Russian knapweed controlled with Milstone herbicide.

EXAMPLE 2a — This area, east of Randlett, is also heavily infested with Russian knapweed. On October 1, 2010 the Weed Department tested a fall application of Milestone herbicide @ 7 oz./Ac + LI700 surfactant after plant dormancy. Red box shows dormant knapweed in application area.

Russian knapweed infestation along Randlett Highway.

EXAMPLE 2b — An inspection in June 2011 showed a near 100% control of Russian knapweed inside the boom path. The red arrows show dead knapweed. The red box shows healthy knapweed outside boom path. Many such scenarios are found throughout the County.

Russian knapweed controlled with Milestone herbicide.

EXAMPLE 3a — This area is on Hwy 191, north of Steinaker. It was reported to the Weed Department in August 2010. It was heavily infested with spotted knapweed covering approximately 2 acres on both sides of the highway. In September 2010 the Weed Department applied Milestone herbicide @ 7 oz/Ac + LI700 surfactant.

spotted knapweed

EXAMPLE 3b — In June 2011, the Weed department inspected the area and found about 95% control of the knapweed. A followup application of Milestone (same rate) was made in September 2011.

Spotted knapweed

EXAMPLE 3c — No photo is available for 2012. A similar amount of knapweed was present in 2012 and a followup application of Milestone was made. In June 2013 (below) no knapweed was found. An incredible result of consistent weed control efforts with the proper herbicide applied at the proper time.

Spotted knapweed

Matt Warner Reservoir Spotted Knapweed
Spotted knapweed near Matt Warner Reservoir in northeastern UtahMany citizens of Uintah County are aware of the vast problems of perennial pepperweed (tall whitetop), Russian-olive, saltcedar (tamerisk) and Russian knapweed within the County. The Weed Department along with partners of the Uintah Basin Cooperative Weed Management Area (UBCWMA) and other volunteers are working hard to prevent another noxious weed from becoming a similar problem. Spotted knapweed has infested the area north and west of Matt Warner Reservoir on Diamond Mountain. Due to massive control efforts, over the past several years, this weed has largely been prevented from spreading. If left uncontrolled, this noxious weed could damage hundreds of acres of prime livestock range and wildlife habitat. The partners of the UBCWMA are committed to controlling spotted knapweed here and throughout Uintah County.


Matt WarnerMatt Warner

The areas circled (below) are newly discovered infestations showing the blue marker dye highlighting a few of the areas above Matt Warner that were sprayed in 2013.

Matt Warner

Private Land Perennial Pepperweed (Tall Whitetop)
EXAMPLE 1a — This property is located on 2500 South Vernal. The Weed Department had been observing the field since 2008 to see how the infestation would develop and to see if the landowner would control the perennial pepperweed to benefit the horses using the pasture. It appeared that the infestation size did not increase or decrease significantly. It appeared that little or no efforts were made for weed control in 2008, 2009, 2010 and 2011. The weeds were mowed in mid-summer of 2012.

Perrenial pepperweed

Perrenial pepperweed

Perrenial pepperweed

EXAMPLE 1b — In September 2012 the Weed Department contacted the landowner and obtained permission to control the weeds. The perennial pepperweed had been mowed and was just coming into full bloom again. After the horses had been removed for the year, Perspective herbicide was applied @ 8 oz/Ac + LI700 surfactant. The pasture was inspected in July 2013 and showed 99% control of the pepperweed. One small strip had been missed and was later controlled by the landowner.

Perrenial pepperweed


Leafy spurge
Leafy spurge is a growing concern in the Uintah Basin. It has infested several areas all around Vernal and is beginning to expanded its range significantly. The Weed Department is trying to map every infestation of leafy spurge to ensure complete control each year. Because herbicides have minimal effect on well established patches, the Weed Department introduced Aphthona flea beetles to the infestation in 2008. It is hoped that the flea beetles will be able to thrive and control leafy spurge in less accessible areas of the County.

Leafy spurge plant and flower

Leafy spurge infesting pasture and nearby home properties.

Saltcedar Biological Control
Occasionally there are bright hopes among the dismal nature of weed control. Saltcedar biological control is one of those bright hopes. Saltcedar is one of those weeds that are extremely difficult to control with herbicides, mechanical or cultural controls. Until recently biological controls had been nonexistent. In about 2002 the saltcedar leaf beetle was approved for experimental release in the United States. A site near Delta, Utah was one of the first release sites and the results have been spectacular. After only a few years of beetle control, hundreds of acres of saltcedar have been exfoliated and killed. Similar results have been documented near Moab, Utah. Several miles of saltcedar along the Colorado River near Moab have been killed by hungry beetles. Native vegetation is left untouched by the beetles so it can flourish. (See top two photos below)

Uintah County received its first beetles from the Moab area in 2006. Several thousand saltcedar beetles were introduced near the Bonanza Bridge south of Vernal, Utah, Stewart Lake near Jensen, Utah, and the Ouray Bird Refuge near Ouray, Utah. An additional transplant of several thousand beetles occurred in August 2007 near the Bonanza Bridge. The beetles are reproducing well and are showing signs of exfoliating saltcedar trees. The bottom photos show a series of exfoliation from August 2 to August 30, 2007 (See bottom two photos below).

More beetles have been introduced in Dinosaur National Monument in Colorado. They are reproducing well and appear to be headed towards Utah along the Green River.

Saltcedar (tamerix) along Colorado River, near Moab, Utah, that has been killed by D. elongata biological controlD. elongata biological control feed exclusively on saltcedar trees allowing the native vegetation to thriveSaltcedar tree prior to saltcedar leaf beetle feeding damageSaltcedar tree completely exfoliated in 30 days by D. elongata insects