Beetles help county keep weed in check |

Beetles help county keep weed in check

Greg Schreier

About 1,000 tiny flea beetles buzzed around the confines of a small paper bag, no doubt ready to feast on a fresh crop of leafy spurge.

The beetles were some of the 6,000 Pitkin County land manager Jim Lewis released Thursday. Patches of leafy spurge ” a noxious weed that is deceivingly attractive, as much as 2 feet tall and thin with leaves and small, yellow buds ” exist throughout Jaffee Park in Woody Creek. Lewis then found a healthy patch of the weed and shook the beetles out of the bag and onto their new home.

Lewis pointed out beetles enjoying the buds and leaves as he walked along the park’s trail. This is the seventh year Pitkin County has released the insects ” not much bigger than ants ” in an effort to control the weed. Lewis released more beetles at Twining Flats and Star Mesa.

Leafy spurge can harm surrounding vegetation and is a major problem along the Front Range. Lewis said it’s not as widespread on the Western Slope, but there are still pockets of growth in the area.

The weed soaks up water and nutrients in the soil and also releases toxins into the ground, preventing other plants from growing near it, according to the National Park Service.

“It’s one of the most difficult weeds to get rid of because the roots can get down 40 to 50 feet,” Lewis said.

A Colorado Department of Agriculture insectary in Palisade donated the beetles, so releasing them is much cheaper than using an herbicide. Plus, the county doesn’t have to pay people to spray or pull the weeds.

The insects eat the buds of the weeds, and their larvae eat the root hairs, which absorb water and nutrients from the soil, so the bugs have a sort of double effect. The beetles don’t eliminate the leafy spurge, but they still help protect native vegetation.

“It doesn’t really eradicate it, but it does keep it in check,” Lewis said. He also said the beetles have been reproducing every year, further helping to keep the pesky plant in check. So far, the county has been able to control the weed’s spread.

A biological treatment is usually tested anywhere from six to 10 years before it’s used, Lewis said. The studies on the flea beetle showed that leafy spurge is about the only thing the beetles eat, and this is the seventh year the county has used the insects. The process is common, and the county uses several types of insects on many other weeds.

The beetles have been successful throughout the state, and Lewis said it’s a much better alternative to using an herbicide. Pitkin County is trying to use as many biological treatments as possible, and Lewis said he hopes to cut herbicide use by one-third to one-half.

The herbicide used on leafy spurge before “was one of the more harsh, restrictive herbicides,” Lewis said, adding that it stayed in the soil for up to a year. “We prefer not to use that herbicide.”

Greg Schreier’s e-mail address is

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