Posted: May 12, 2015

If you have been following the news, you’re aware of a damaging little insect called the Emerald Ash Borer (EAB). Although it wasn’t spotted in the U.S. until 2002, it has certainly made a name for itself. EAB has been confirmed in Winona and Olmsted counties, and most recently in Fillmore county. At Maier Tree and Lawn, we’ve been tracking the progression of EAB in the Winona and Rochester area since it was first spotted.

What is the Emerald Ash borer, and what makes it so dangerous? First of all, it is an invasive species. That means it isn’t native to the area and doesn’t have the natural limitations to spreading as it does in its native China and Southeast Asia. The preferred diet and place of incubation for EAB is ash trees. In its native land, ash trees are of such a variety that they are able to resist the shiny green insect. Not so here in the U.S.

It is believed the Emerald Ash Borer made its way to North America by hitching a ride across the Pacific on shipping crates made of an Asian variety of ash lumber. Once here, it found a veritable banquet of ash trees to feed upon and nurture the larvae. Since it has no real predators and our ash trees lack natural resistance, the Emerald Ash Borer is pretty much left unchallenged as it multiplies its way across the country.

There are, however, steps that can be taken to limit the advance of EAB. A simple action everyone can take is to not transport firewood into or out of parks and campgrounds. Once moved to a new location, EAB will seek out ash trees to lay their eggs upon. By observing this easy to follow practice, everyone can help stop the advance of this invasive species.

If you have ash trees on your property, you need to be aware of signs of infestation and how to prevent it from establishing a foothold. Because the Emerald Ash Borer is difficult to detect early, it’s a good idea to contact a professional arborist if you have questions or concerns. Maier Tree and Lawn can examine your ash trees and perform a risk assessment. Our arborists know where there have been sightings of the insect and how likely it is to reach your property.

If EAB is present, there are several methods of treating ash trees with an effective insecticide to stop it. There are three common methods of applying these insecticides. An arborist will know which will be most effective for your situation. These methods are:

    • Above ground application. This methods applies either a liquid or granules around the base of the tree.
    • Inject chemical into soil. In an area where run-off is a problem, it may be advisable to have the insecticide applied several inches below the surface of the soil.
    • Injection into tree trunk. To inject an insecticide into the trunk, holes are drilled into the tree near the base and the chemical is delivered directly into the tree.

Each of these methods is intended to get the insecticide into the tree’s system to flow throughout the tree. The reason it is so important to get an insecticide into the tree is to stop the larvae that bore their way into the tree to incubate. As they bore their way into a tree, they block the natural flow of nutrients throughout the tree, essentially starving it to death.

Trees also need to be treated every few years to continue to resist the invading insect, based on your consulting arborists recommendations. The cost of treatment and prevention may seem expensive, however, studies have shown that treating a tree is less expensive that having a mature tree removed, and it will preserve a resource that can take decades to mature.

If you have any questions about the risk to your healthy ash trees or treatment of a tree, contact Maier Tree and Lawn. As we like to say, “At Maier Tree and Lawn, we care about trees and all things green and growing.” We do our best to stay on top of the Emerald Ash Borer threat and methods to stop its spread. To protect your ash trees, contact us at 507-286-8733 in Rochester, or 507-454-7000 in Winona.

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