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Take up battle vs. emerald ash borer


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Guess what time it is? It is time to protect your ash trees. The emerald ash borer insect has been confirmed in just about every Indiana county, including Johnson.

To see a map of where the insect has been confirmed in Indiana, visit extension.entm.purdue.edu/eab.

Let’s clear up the rumors, this invasive pest was not killed by the cold winter. Experts are still advising everyone to move forward with a management plan. Here are a few quick background facts:

  • Emerald ash borer kills 99.9 percent of the untreated ash trees it attacks.
  • The adult is a shiny green, winged insect that fits on a penny.
  • The worm-like larvae hatch in July and feed under tree bark all summer.
  • Early signs of infestation include a thinned tree canopy, woodpecker damage, and bark splitting.
  • Later signs of infestation include branch dieback in the upper third of the tree and sprouts that appear at the trunk.

The best insecticides for saving your ash trees contain imidacloprid and should be applied before June. Always follow label directions.

If ash trees are not important to your landscape, planted in a poor site, or showing many outward signs of infestation, then saving it may not be your plan.

However, healthy ash trees that you want to keep may be able to be protected by using insecticides. If more than 50 percent of the tree’s leaf canopy is still there, then the tree can be saved.

If you invest in insecticides over the next few years, keep in mind that having a tree in your yard provides benefits such as adding value to property, increasing air quality, intercepting storm water runoff, reducing soil erosion, blocking wind, etc.

Spending money to prevent your ash trees from being infested truly is an investment. Some insecticides can be bought and applied by a homeowner. If you measure a tree trunk diameter at about 4.5 feet from the ground and it’s over 20 inches though, you will need to hire a professional. The Johnson County Purdue Extension office can recommend tree care companies. Our number is 736-3724.

It is even possible to talk with neighbors or your homeowners association about getting a group rate on professional tree services. Also, if your neighborhood is interested in an educational program, I can come out and do that.

Huge amounts of other great information are on the previously mentioned website as well. You can even use a cost calculator to determine your options for treating a tree versus taking it down and replacing it. Remember to plant a diverse mix of trees to increase resiliency to future pest problems.

Sarah Hanson is the agricultural natural resources extension educator through the Johnson County Purdue Extension. She has a master’s degree in animals and public policy from Tufts University, Cummings School of Veterinary Medicine and a bachelor’s degree in animal science from Purdue University. Send comments to letters@dailyjournal.net.

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