Emerald Ash Borer may not be in Omaha Park | TSLN.com

Emerald Ash Borer may not be in Omaha Park

Worried that the emerald ash borer is in your ash tree?

Are you wondering if the emerald ash borer (EAB) is here, in your yard, perhaps in your community in western Nebraska? Have you had neighbors or other persons tell you it is already here? Well the fact is that it was found in an Omaha park and in Cass County in June of 2016 but it has not been confirmed nor identified in western Nebraska by the Nebraska Forest Service or the Nebraska Department of Agriculture.

If you have heard directly from someone that it is here, that is not correct. If you have an insect which is suggested to be the EAB, you should have the insect identified and passed along to one of the agencies noted above. Rachel Allison, western forest health specialist with the Nebraska Forest Service said that it is very likely that it is another insect that has already been here, like the lilac (ash) borer or other tree borer, which has been associated with ash trees for many years. "These insects are prevalent in trees that are stressed by drought, early cold and later spring freezes, overwatered lawns, as well as lawn herbicides used to kill dandelions and other weeds. Most importantly, these insects that are here now and are the real culprit in western Nebraska need to be treated differently than what would be used for the EAB."

What happens if you do treat your ash tree before EAB gets to your community? There is the possibility that EAB may not reach the western communities for several years, or if it does arrive in a year or two, we will see it in other communities as it advances or moves across the state. Treatments for EAB are usually applied by one of two methods; injection or soil drench. If you decide to have the tree injected, what happens is that the tree will be damaged some by the injection, and also, each time the tree is injected over the years the tree is damaged more and more. It is best to wait until EAB is known to be close by before beginning treatments so that the damage to the tree can be minimized.

How do bark injections damage the tree? Drilling a hole and applying a liquid under the bark of the tree creates an area of dead tissue and after several applications with multiple injection sites makes it difficult for the tree to move the water and nutrients it needs to survive. The tree reacts to these injected sites as a wound and develops defensive tissue, restricting and directing the normal flow of healthy tissue away from that area. Yearly or even every other year injections eventually end up blocking the flow of very important water and nutrients from the ground to support and maintain the health of the tree.

The other method, a soil drench, is not only harmful to the tree but it will also harm other beneficial insects in the soil around your ash tree. Those insects help to create living soil, very important to nutrient break down and development of organic matter critical for a healthy tree and plant survival. While it may seem simple to apply the pesticide and directly target the problem insects, research shows that this product, imidacloprid, leads to the decline of many insect, butterfly and bird species. There are also several limitations to consider when applying the soil drench—the pesticide cannot be used in all locations, particularly wet, sandy or compacted sites typical of some yards where trees are found. Also, a soil drench has restrictions for the amount that can be placed within a city block.

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What should you do? Allison suggests that first, don't apply a pesticide when you're not sure of the reason for the treatment, or not sure if you have EAB. Second, learn why the treatment for EAB is both damaging to the tree and harmful to the environment. Third, if you have an ash tree and are concerned about its health and the possibility of EAB being present, visit this website http://eabne.info/ for information or email your question to this site trees@unl.edu.

–Nebraska Forest Service

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