Home & Garden

5 things to know about the emerald ash borer

Emerald ash borer
Emerald ash borer File photo

The emerald ash borer is a devastating pest that has wiped out hundreds of millions of ash trees in North America. It’s been found in half of the United States, including Kansas.

Some local companies have been advertising treatments to prevent the ash borer. But owners of ash trees in the Wichita area should not jump at the chance, according to Sedgwick County extension agent Matthew McKernan. Here are five things you need to know about the borer, with information from McKernan:

1. The emerald ash borer has not been found in Wichita

The closest place it’s been found is the Kansas City area. It was found in Wyandotte County in 2012, Johnson County in 2013, Leavenworth County in 2014, and Douglas and Jefferson counties in 2015. “There are a lot of organizations monitoring for it in this area,” McKernan said. “That’s why we can be fairly certain that they’re not here yet.”

2. Damage to trees in Wichita could be many years away

The borer is a very slow mover. In five years in Kansas it’s only moved two counties in any direction. If it’s traveled long distances, the most likely way is as a hitchhiker in infested firewood or on vehicles such as campers. But there are quarantines in place that forbid the moving of ash wood out of affected counties.

“Even when we get the emerald ash borer in Sedgwick County, it does not mean every tree will have the emerald ash borer at that time,” McKernan said. “The population has to build up.” Just as an estimate, he says that “in the first maybe five to eight years you’ll see a few trees dying. Then in two to three more years you see more trees dying. It may be 15 years or more before a significant majority of the ash trees are infected or have died because of it. People don’t need to worry because it’s found. It’s not every tree that has it.”

The Wichita area also has less of a density of ash trees than some other parts of the state. Wichita is on the edge of the native range of ashes in Kansas; there aren’t any native ash trees in western Kansas.

Proper removal and disposal of infected trees help prevent its spread, as does not transporting firewood from site to site.

3. The best thing to do now is maintain tree health

The best thing you can do now is keep trees healthy, because while healthy ash trees are still susceptible to the borer, they are less likely to be infested.

In addition, if you’re planting trees, don’t choose an ash, because all types of ash are susceptible to the borer. And if you have an ash tree that’s already in decline, don’t spend a lot of money trying to get it back to health.

When the borer is confirmed in a county, treatment is recommended in a 15-mile radius of where it is found, but only for trees that are of historic and significant ornamental importance, or that offer considerable shade.

4. There are several symptoms of an infested tree

The symptoms that a tree may show if emerald ash borers are at work include significant branch dieback, water spouts or suckers on the trunk, small D-shaped holes in the wood, increased woodpecker activity, and bark splitting off the tree.

5. Premature treatment is expensive and potentially harmful

Any treatment for emerald ash borers must be done as a prevention, not after a tree has them. The benefits of treatment last only one to two years, depending on whether you go with a soil drench or injection. If injections are started too soon, they make unnecessary holes and wounds in the tree in addition to causing unneeded expense.

Annie Calovich: 316-268-6596, @anniecalovich