Emerald Ash Borer Could Be Coming Your Way

What you need to know.

Emerald ash borer has worked its way through 11 states and claimed tens of millions of trees. This tiny metallic green invasive insect kills all types of ash trees in Minnesota (except Mountain Ash). On its own this insect can only move up to 10 miles per year, but the transport of firewood has helped to speed this little green insect to Minnesota.

The biggest concern about the emerald ash borer is that you will more than likely notice your ash tree dying before you ever see the insect responsible for its decline. What it lacks in size, it makes up for in destruction.

Symptoms of EAB on ash trees include:

Significant Crown Die-Back

The crown die-back is not associated directly with the feeding of the insect on the tree but rather as a result of the damage that has been done to the water and nutrient conducting vessels under the bark. Water and nutrients can no longer make it to the top of the tree and the crown begins to slowly die.

Epicormic Sprouts

In response to crown die-back, the tree begins to produce a large mass of branches and leaves (epicormic sprouts) usually along the main trunk.

S-Shaped Feeding Galleries Underneath the Bark

When the bark is pulled back from a declining tree, the telltale s-shaped feeding galleries can be seen as evidence of the presence of EAB.

D-Shaped Exit Holes

The characteristic D-shape is a result of the feeding pattern of the flat-headed borer as it makes its way through the bark and out of the tree to begin feeding as an adult on the leaves.

In the fall the adults will lay eggs in the cracks and crevices of the tree. When the eggs hatch in the spring of the following year they burrow through the bark and begin to feed underneath the cambium. The cambium is a thin layer of living tissue underneath the bark that is responsible for movement of both water and sugar up and down the tree. When the cambium has been girdled by the borers it can no longer send sugars and water up and down the conducting vessels, essentially killing the tree.

Treatment Options:

Soil Injection

• Insecticide: Imidacloprid
• Injected into the soil
• Most effective when applied preventively
• Most affordable option
• Apply annually in spring or fall
• Cannot be applied near surface water

Trunk Injection

• Insecticide: Emanectin Benzoate (Tree-äge™)
• Injected into the trunk
• Still effective if the tree is slightly infested
• More expensive treatment
• Apply every two to three years
• Can be applied near water
• Proven to be more effective today

We can help save your ash. Treatments, while not 100% effective, are available for your valuable ash trees. Call an arborist today for more information: 651-451-8907.