Beetles eat tamarisk trees |

Beetles eat tamarisk trees

COLORADO SPRINGS, Colorado ” Chinese beetles are being enlisted to fight an invasive tree species that is choking stream banks across the West.

Officials looked to the ladybug-sized beetles when they looked for ways to combat tamarisk trees. The trees are Asian natives that have choked out native life on stream beds from Fountain Creek in Colorado to the Arkansas River basin.

In Asia, Chinese beetles have a taste for the leaves of the tamarisk, so agriculture and forestry officials are putting the beetles on tamarisk trees here. So far, scientists are happy with what they see.

“It’s virtually free,” said Dan Bean, director of Colorado’s Palisade Insectary, where the beetles are bred. “Compared to going with bulldozers, it’s way cheaper. The beetles defoliate the trees, and they’re extremely specific.”

Colorado agriculture officials started using the beetle control this summer by releasing more than 26,000 of them near Pueblo. In Utah, land managers have been using the tamarisk beetle, or salt cedar leaf beetle, to control tamarisk trees since 2006.

Tamarisk, also known as salt cedar, was brought to the U.S. in the 1800s as an ornamental tree and to protect stream banks from erosion.

But with no natural controls, tamarisk spread and began taking over river and stream banks. It has overtaken native cottonwoods along most of Colorado’s rivers, and the Arkansas River is the most infested in the state, according to a 2006 report by the Grand Junction-based Tamarisk Coalition. Fountain Creek and the Huerfano River have the most tamarisk of any tributaries in the state.

A single tamarisk tree can consume 200 gallons of water a day. The report said the Arkansas River and communities that depend on its water, including Colorado Springs, are losing more than 17 trillion gallons of water per year to tamarisk.

It can cost up to $1,000 an acre to remove tamarisk trees, with yearly follow-up checks to make sure it is not re-growing.

Agriculture officials in Colorado say the beetle control appears to be working. Late-summer checks of revealed no beetles on the tamarisk, conservation service biologist Patty Knupp told The (Colorado Springs) Gazette.

A botanist for the U.S. Bureau of Reclamation told the newspaper that even holding the tamarisk in check in a victory for land managers. Even if the beetles don’t kill a tamarisk tree, they can remove enough leaves to allow more sunlight to reach native plants below.

“You can release the beetles and they don’t actually kill everything but they do tend to hold it in a static state, so we don’t see an increase in salt cedar populations,” botanist Denise Hosler said.

Biologists say the beetles don’t always solve the problem of invasive salt cedar trees. But Bean said there’s no question the beetles are helping slow the growth of invasive tamarisk trees.

“The beetles have come a long way,” he said.

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