June 22, 2005

New Bug Chewing Ash Tree Leaves in N.D.

BISMARCK, N.D. (AP) -- A bug that chews on the leaves of certain types of ash trees is making its first appearance here, foresters say. It also has been spotted in Fargo. Its name is cottony psyllid, or jumping plantlice, and it is known for its appetite for fall gold black ash and mancana ash trees.

"Before this year, I'd never seen it and never heard anyone talk about this insect," said Jeff Heintz, Bismarck's assistant city forester.

"We're seeing it worse in the south half of Bismarck," he said. "I'm not sure why that's happening. But based on the numbers, this insect must have been here last year."

The cottony psyllids, which measure only about a tenth of an inch, fly and jump around while on the trees.

Heintz said the cottony psyllid is a native of Europe, but likely entered the United States from the Canadian province of Alberta, where large numbers of the insects have been seen in recent years. They could have ridden the wind south, or come in with nursery stock or by someone who visited Alberta and inadvertently brought them back, he said.

The psyllids are leaf-eaters, and their chewing causes leaves to curl up and die. A white, cotton-like substance is often left over, lending to the insect's name.

In Calgary, Alberta, where the psyllids have been a problem for three or four years, the insects have been killing some of the ash trees, particularly those under drought stress, Heintz said. Green ash trees appear to be safe, he said.

Heintz recommends giving trees at least an inch of moisture a week.

The psyllids can be killed by using certain kinds of chemicals, including insecticidal soap, Heintz said. But it might be better to wait to apply chemicals right after they hatch, he said.

Most of the insects now are in the adult stage, he said, but they could have three hatches this year.


Information from: Bismarck Tribune, http://www.bismarcktribune.com