Uintah County  

Successful Noxious Weed Control Projects

The Weed Department is involved in dozens of weed control projects each year. From county properties to private lands to large-scale public land projects for UDOT, UDWR and BLM, the Weed Department is committed to controlling noxious weeds wherever they may grow. To be be truly successful, the Weed Department tries to monitor and control weeds in as many of these same locations every year. Showcase Projects — Rights-of-way Private LandsUDWRLeafy Spurge

The Weed Department is required by law to control noxious weeds on its properties the same as required of each citizen. We also strive to control nuisance vegetation, such as kochia, Russian thistle, dandilions and other weeds on properties the County controls. Our goal is to provide aesthetically pleasing and safe areas for the citizens and visitors of Uintah County.

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

Russian knapweed along a county road

A view of 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 2 Russian knapweed — 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./acre + LI700 surfactant after plant dormancy. Red box shows dormant knapweed in application area.

Russian knapweed infestation along Randlett Highway.

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 3, Spotted knapweed — This area is on Hwy 191, adjacent to BLM property northeast of Steinaker. A concerned citizen reported it to the Weed Department in August 2010. The area was heavily infested with spotted knapweed covering approximately 1 acre on both sides of the highway. In September 2010 the Weed Department applied Milestone herbicide @ 7 oz/acre + LI700 surfactant.

spotted knapweed

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. The Weed Department continues to monitor this site annually to control a small number of knapweed plants that continue to sprout due to a large seed bank and long seed viabilty.

Spotted knapweed

No photo is available for 2012, but 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

UDWR, BLM and Private lands near Matt Warner Reservoir
Spotted knapweed near Matt Warner Reservoir in northeastern UtahSpotted knapweed — The vast problems of perennial pepperweed (tall whitetop), Russian-olive, saltcedar (tamerisk) and Russian knapweed are no secret to the citizens of the County. There are several other noxious weeds that are just as destructive as those previously mentioned, but they are being contained by the Weed Department, UDWR employees and other volunteers

Spotted knapweed is one of those weeds that has infested the area north and west of Matt Warner Reservoir on Diamond Mountain. Due to massive control efforts, since before 2007, this weed has largely been prevented from spreading. If left uncontrolled, this noxious weed could severely damage hundreds of acres of prime livestock range and wildlife habitat. The Weed Department is fully 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 Lands
EXAMPLE 1, Perennial Pepperweed (Tall Whitetop) — This property is located near 2500 South in Vernal. The Weed Department observed the field from 2008 to 2011 to see how the infestation would develop. It appeared that the infestation size did not increase or decrease significantly. It was apparent that little or no efforts were made for weed control during that time. The weeds were mowed in mid-summer of 2012.

Perrenial pepperweed

Perrenial pepperweed

Perrenial pepperweed

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, Telar herbicide was applied @ 1.3 oz/Ac + LI700 surfactant. The pasture was inspected in July 2013 (below) and showed 99% control of the pepperweed. One small strip had been missed and was later controlled by the landowner.

Perrenial pepperweed

Example 2, Russian-olive —


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 Delta 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 thrive

Saltcedar tree prior to saltcedar leaf beetle feeding damageSaltcedar tree completely exfoliated in 30 days by D. elongata insects