Emerald Ash Borer

June 8, 2016
  • Emerald Ash Borer EAB

Emerald Ash Borer

After years of warning, the Emerald Ash Borer beetle, or EAB for short, has been officially reported here in Omaha, Nebraska. Unfortunately, this unwelcome guest will start killing the 44 million ash trees in the Omaha and surrounding communities, as it has done in other communities in the Midwest.  Here are some facts about the Emerald Ash Borer, so that you can protect your beloved trees in the most informed way possible.

Is the Emerald Ash Borer in Nebraska yet?

Yes. Mayor Jean Stothert and The U.S. Department of Agriculture confirmed on June 8, 2016 that Emerald Ash Borer has been found in ash trees removed from Pulaski Park at 40th & G Street. You can check the Nebraska Department of Agriculture press release or Mayor Stothert’s website if you are concerned about an outbreak.

What is the Emerald Ash Borer anyway?

The Emerald Ash Borer is an Asian beetle that arrived in the United States around 2002, probably via wood shipped from Asia. It is a small bug (1/2 inch long as an adult), and bright metallic green in color. The inch long larvae are white with brown heads, and a 10-segmented body with bell-shaped segments near the back end, and are found in S-shaped grooves underneath the bark of the tree trunks of its victims.

Emerald Ash Borers lay eggs in tree trunks, where the larvae grow, creating huge patterns of the S-shaped patterns mentioned earlier. These grooves disrupt the flow of nature and nutrients that the tree needs, and can ultimately kill a fully grown ash tree. Unlike other boring insects that typically target only unhealthy trees, EAB will target a completely healthy ash and can kill it within two to four years.

How do I know if I have it?

If you are worried your ash trees may be infected with the Emerald Ash Borer, look for these symptoms: galleries of S-shaped grooves underneath the bark, cracks and splits in the bark, death of the upper canopy of the tree, D-shaped exit holes in the bark, and water sprout growth around the trunk. Remember, these beetles only target ash trees, so if you’re seeing signs in something other than an ash, it is not EAB.

Symptoms of Emerald Ash Borer

  • Canopy thinning
  • Branch dieback, usually beginning in the top of the tree
  • Bark splitting
  • Zigzag tunnels below the bark
  • D-shaped exit holes 1/8 inch across
  • Bark stripping from woodpecker activity

Can I protect my tree before it gets here?

Short answer: Yes, but… long answer: Yes, there are ways to protect ash trees from EAB. There are injections you can give a tree by boring into the bark, bark spraying applications or soil drenching. However, these are not magic solutions. The homeowner option, a chemical soil drench around the base of the tree, is not adequate to protect larger ash trees and can damage other plants in the area as well as bees and other pollinators. Tree injections, which must be done every one to two years requires drilling a hole into your tree, which puts it at risk for fungi or pests, and breaks through barriers meant to protect your tree from internal decay. It’s best to avoid injections for now until the outbreak worsens. Barks sprays are the best option in our opinion.  These require spraying the bark from the ground up to shoulder height.

The point at which to protect a tree is when EAB has been detected within 15 miles. This gives your tree protection while minimizing harm to the surrounding area. The best trees to protect are the healthy, beautiful ash trees that you value the most. If not, consider planting different types of trees, to take the place of your ash in case something happens.

Can I spray my own tree?

Yes, and no. There are consumer products that work well for smaller trees such as Bayer Tree & Shrub 2.94% Imidacloprid and Hi Yield Systemic 1.47% Imidacloprid.  If you have a tree with a diameter of 6 inches or larger you may need commercial products such as Dinotefuran 20%.  Hiring a professional, licensed pesticide applicator to do these treatments will be better for the long term of the tree. We cannot urge you enough to be proactive and to get a plan in place if you have an ash tree. Please also keep in mind that all of these products are extremely toxic to bees and aquatic invertebrates

Can an infected tree be saved?

If EAB infects a tree, there is a chance to save it. If the infestation has been caught early, the tree can be treated, even if there is significant canopy damage. However, time is of the essence in this case, because trees over 50 percent damaged are much less likely to recover, as are trees that were already damaged or unhealthy.

Does EAB spread?

Yes! EAB spreads mostly because of humans.  Moving infested firewood and nursery stock is the leading cause. To prevent the spread, moving firewood and nursery stock out of infested areas is regulated by state and federal quarantines. Avoid spreading EAB and other wood-infesting pests by purchasing firewood where you will burn it. Don’t bring wood with you when you travel. Leave unburned wood at the camp site.

If you think you have EAB, contact the Nebraska Department of Agriculture at 402-471-2351 or the national EAB hotline at 866-322-4513.

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