For Immediate Release:  June 25, 2007 
Contact: Mel Lloyd BLM 970-244-3097

Using biological control to manage tamarisk

MONTROSE, Colo. — The Bureau of Land Management Uncompahgre Field Office (UFO) and the Colorado Department of Agriculture, Palisade Insectary, are partnering to introduce Diorhabda elongata deserticola Chen, the tamarisk leaf beetle, to portions of southwestern Colorado in an effort to biologically control tamarisk.  First released in Colorado in July 2005, the tiny beetle is showing promise in controlling tamarisk, or saltcedar, a non-native and invasive plant from southern Eurasia that was first introduced to the United States in the early 1900s as an exotic.  The Diorhabda, which came from nurseries in Lovelock, Nevada, were released earlier this month at an undisclosed site along the Dolores River in western Montrose County.  Authorities hope it will be only the first of several releases this summer at select sites in an effort to curb, if not eradicate, the pesky tree. 

“We’ll begin monitoring the site in July and continue to do so for at least the next five years,” Insectary Director Dan Bean said. “We’re hopeful that Diorhabda will help us return our waterways and riparian areas back to prime habitat for native willows and cottonwoods throughout the West.”  Bean has been involved with leaf beetle research for many years and also heads up the Biological Pest Control Program, which targets noxious weeds with its native predators.  Bean and Insectary staff member Sonya Ortega are working closely with Lynae Rogers, weed program manager for UFO.

“The Insectary staff has become an extension of our staff, taking on monitoring these sites to help us ensure a successful project,” Rogers said.  “Dan and his crew bring an in-depth knowledge and understanding to the project that result in a great relationship that’s good for both the Palisade Insectary and the BLM.”

The beetle, by feeding exclusively on tamarisk, has the potential to become an effective natural control for the tamarisk plant.  Without the beetle, tamarisk in the New World have flourished, crowding out native species, threatening them with extinction and impacting water supplies as the thirsty tamarisk choke river bottoms, stream beds and riparian areas in nearly every state west of the Mississippi River.

One appeal of the beetle is cost effectiveness. Manually removing tamarisk stands can cost $1,500 to $3,000 per acre.  By comparison, the tamarisk leaf beetle offers treatment of tamarisk stands for less than $10 per acre.  It is hoped that the beetle will spread to other tamarisk stands and become a permanent check to the invading plant.

The beetle is also a natural fit to the West because of a similar latitude and climate as that of Eurasia.  The beetle has limited effectiveness south of the 38th parallel because the beetle requires 14 or more hours of sunlight or it goes into hibernation.  Work continues in the Old World to find Diorhabda insects that will be effective south of the 38th parallel.

The Colorado Department of Agriculture has played a key role in the development of Colorado’s tamarisk leaf beetle program.  All Colorado sites have been selected on the basis of their suitability for rapid population growth of the beetle and for being in areas removed from insecticides that could impact a new population of insects.  The Department of Bioagricultural Sciences and Pest Management at Colorado State University manages the release sites in Colorado.  The Insectary at Palisade, Colorado, operated by the Conservation Services Division of the Colorado Department of Agriculture, plays an important role in the release and monitoring of the insect.

For information about the UFO tamarisk project, contact Lynae Rogers at (970) 240-1068.  To learn more about the Palisade Insectary programs, contact Dan Bean at (970) 464-7916.

-BLM-