Scientists may have a new weapon in cheatgrass war

Western land managers may have a new weapon in their frustrating – and so far losing – battle against invasive cheatgrass.

The U.S. Fish and Wildlife Service says early field tests of naturally occurring soil bacteria known as ACK55 show promise in controlling alien cheatgrass, a native of Eurasia that was accidentally introduced by settlers in the 1800s.

Cheatgrass has taken over millions of acres of federal land in Nevada and other Great Basin states, promoting huge, fast-moving wildfires that destroy sagebrush habitat and with it, food and shelter for pronghorn antelope, sage grouse and mule deer.

Scientists have for years looked for a biological agent to fight the plant pest. At the U.S. Forest Service Shrub Sciences Lab in Provo, Utah, research ecologist Susan Meyer has focused on a fungal disease, nicknamed the “black fingers of death,” that attacks dormant cheatgrass seeds by injecting a toxin that stops germination.

ACK55, a strain of Pseudomonas fluorescens, was discovered by a federal soil microbiobioloist, Ann C. Kennedy, during research on weed-suppressing bacteria. It affects the developing root cells of cheatgrass and a few other invasive plants, according to researchers, but does not harm wheat, native bunch grasses or broadleaf plants.

In field trials in Washington, the Fish and Wildlife Service says, the amount of cheatgrass fell substantially three to five years after a single application of the native soil bacteria. Another field trial is underway in Idaho.

“I’m convinced it will work as long as the bacteria are applied in the fall to the soil so they can colonize emerging cheatgrass roots in the spring,” Fish and Wildlife biologist Michael Gregg said in a statement.