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What You Need to Know About the Emerald Ash Borer

September 20, 2017

The emerald ash borer is a beetle that feeds off of the inner bark of ash trees, which affects the tree’s ability to transport nutrients. This pesky little beetle is responsible for killing hundreds of millions of ash trees in North America, and in 2013, it was spotted in Boulder, Colorado. Since one in six trees in Denver are ash trees, it is crucial that these pests do not make their way into the city. The city launched a campaign last year to try to keep the emerald ash borer out of Denver, however Denver landscaping companies have already been treating ash trees for these pests. Learn more about the emerald ash borer and prevention.

Therefore, it’s important to learn about the emerald ash borer so you can spot the warning signs and take action quickly if you happen to spot an infested tree. Here’s what you need to know:

Vulnerable Trees

The emerald ash borer feeds on all species of ash trees—including both those that are in woodlands and landscaped areas. Some of these beetles have been found within white fringetrees in Ohio, however it is believed that this was an isolated incident and that the beetle does not typically feed on this type of tree. The beetle typically targets trees that are already stressed, however that does not mean healthy trees are safe from this pest. Healthy trees are often targeted and can die within three to four years after they become infested.

Identifying Ash Trees

Knowing that emerald ash borers attack ash trees doesn’t help unless you know what an ash tree looks like. There are three things you should look for to determine if you have ash trees in your yard. First, look for a distinct diamond pattern in the bark of the tree. The bark does not form perfect diamonds, but it should be fairly obvious that the bark is creating a diamond-like shape if it is truly an ash tree.

The second indication that you have an ash tree is the presence of compound leaves. This means that each stem growing off of the branches has multiple leaflets as opposed to one single leaf. There are usually between five to nine leaflets per stem on an ash tree.

Finally, look for opposite branch growth on the tree’s limbs. The branches of ash trees grow in pairs, meaning that for every branch stemming from an ash tree limb, there will be another similar branch growing on the exact opposite side of that limb. If a tree has all three of these characteristics, it is definitely an ash tree. Remember, ash trees are incredibly common in the Denver metro area, so it is very likely that you have at least one somewhere near your home.

How to Spot Emerald Ash Borers

There are certain signs that indicate your tree could be infested with emerald ash borers. First, look for small, d-shaped holes in the bark of your tree. These small holes are created when the adult beetles emerge from the inside of the tree. If you suspect that the tree is infected, you can also remove a small portion of the outer bark so the inner bark is visible. Larvae feeds on the inner bark, and as they do, they create very noticeable s-shaped patterns in the bark. The outer bark conceals these marks, which is why spotting an infestation can be so challenging.

You can also look for the actual beetle itself, although this may be hard to spot. Adult emerald ash borers are metallic green and about the same size as a grain of rice. The larvae, which hide in the inner bark, are lightly colored and less than two inches in length.

Trees that are infested will have a hard time transporting nutrients and water to the top branches. As a result, the canopy of the tree may start to lose its leaves as the branches slowly die. Infested trees will also start to sprout new branches—usually right near where the larvae are feeding—so keep your eyes peeled for new and unusual branch growth. Another sign that your trees could be infested is the presence of woodpeckers, which feed on emerald ash borer larvae. Of course, seeing a woodpecker does not mean that your tree is definitely infested. However, if you begin to see woodpeckers along with other signs of infestation, this indicates there could be emerald ash borers inside your trees.

Similar Looking Beetles

Don’t panic if you happen to spot a metallic green beetle on one of your trees. The emerald ash borer is known for its bright color, but it’s not the only beetle with this coloring. Blister beetles are also green, however they are typically found on the ground or on short plants and flowers. Japanese beetles are green, but they also have white spots around their body and copper-colored wings. Another green-colored pest is the tiger beetle, which is just as shiny and metallic as the emerald ash borer, but not nearly as destructive. If you spot a green-colored beetle, contact a tree service company right away so they can determine if you have emerald ash borers.

Be Defensive

Ideally, you should put a plan in place to protect your trees from the emerald ash borer instead of waiting to call for help when you spot the signs of an infestation. If you have ash trees in your yard, it’s best to contact a tree service company to discuss your options even if you do not believe they are infested. Many people decide to replace their trees with other species that aren’t targeted by the emerald ash borer, however this is not the only defense plan that is available.

Do you want to learn more about pest management? If so, contact the professionals. Arbor Garden is a locally owned and operated tree services company that specializes in tree pruning, removing, stump removal, planting, and pest management. Contact us today to learn more about our tree and integrated pest management services and receive a free estimate.