Ash borers out earlier in warmer spring

Emerald ash borer
The emerald ash borer is responsible for millions of dollars of damage to ash trees in Michigan, and it's spreading to other states. The adult borer is a metallic, coppery-green color and one-third to one-half inch long.
David Cappaert, Michigan State University

The early springtime weather means the emerald ash borer beetle has emerged earlier than usual.

Ralph Sievert, director of Park Forestry for the Minneapolis Park Board, said people should take steps to help stop the spread of the tree-killing bug.

Sievert said the larvae from the beetle eat their way into trees, destroying the tree's ability to absorb nutrients. He said one way to prevent the spread of the beetle is for people to hold off on pruning ash trees until this fall.

"Ideally, you want to get any ash tree removal or ash tree pruning done before May 1, so you've done it before that beetle has emerged," Sievert said. "If you do it after the beetle emerges you have a better chance of the beetle moving around when you take the wood someplace to dispose of it."

The state's agriculture department has banned the transport of ash wood outside of Hennepin, Ramsey, Houston and Winona counties.

Meanwhile, Minnesota agriculture officials are encouraged by the initial results of a new way to find emerald ash borers.

The Minnesota Department of Agriculture recently finished the first year of a three-year study to detect the destructive tree pest.

Researchers sampled branches from 300 trees in the original Minnesota infestation area in St. Paul and up to four kilometers away.

Twenty of the 300 sampled trees were found to be infested with emerald ash borer. Of those 20 trees, only one was outside the core infestation.

Scientists say they found fewer infested trees than expected. And, there were low numbers of the beetles in the infested trees.

An official says that's likely due to efforts to remove and destroy infested trees in Minneapolis and St. Paul.

(The Associated Press contributed to this report.)

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