Emerald Ash Borer
Since the Emerald Ash Borer arrived in the United States in 2002, hundreds of millions of ash trees have been destroyed. The pest, which originated in China and accidentally arrived in the U.S. in wooden packing materials, has cut a devastating swath through forests and gardens. Emerald Ash Borer (EAB) attacks all varieties of ash trees; the trees have no natural defenses against this insect and can die within three years of infestation. The 1" adult insects have intense green, elongated bodies. The adult insects themselves cause little damage; it is the hungry larvae, which gnaw channels into the sapwood beneath the bark, which ultimately disrupt the tree's ability to distribute water and nutrients. There is a window of opportunity for treating trees to prevent or control infestation but it is narrow. Property owners with ash trees must be diligent if they live in an area where the pest is present.
Emerald Ash Borer Information NetworkNebraska Forest ServiceInsecticide Fact Sheet (PDF)
In early spring, adult borers emerge from infested trees, leaving inconspicuous D-shaped exit holes behind them. They mate after the ash leaves have established in spring (early May to mid-June). The females feed on the leaf margins for several weeks, but typically cause little damage to the foliage. Each female deposits 40 to 70 individual eggs into cracks or crevices in the bark of the ash tree. Larvae hatch in approximately two weeks and bore through the bark into the sapwood.
When EAB is present or has been discovered within a 10-mile radius, preventative measures should be taken. There are multiple application methods and options available depending on the level of pressure due to beetle population density. When the tree has lost 50% of its canopy, removal of the tree is the safest option. It is important to properly dispose of all wood from infested trees. EAB larvae can survive in firewood; to avoid the spread of EAB, wood should never be transported to another area.
Should I treat or remove? Follow these steps to help you decide...
Get the Facts
- Consult an ISA Certified Arborist to determine if your tree is a good candidate for treatment.
- If your tree has structural concerns, root compromise or vascular decline we may advise against treatment.
- Provided your tree is determined to be in good health, we will outline the treatment options, which are primarily based on tree size and time of year.
- If you are in the Lincoln area, we are recommending preventative treatment as EAB has been confirmed in Lincoln.
Pros & Cons
- The good news is preventative treatments are showing excellent results, and when done properly, survival rates are nearly 100% with the tree injection options.
- The bad news is you may have to keep treating your trees every 1-2 years (depending on product used). This pest is relatively new to the US, and with no natural predators to help us out we don't know how long they will be around. If you decide to treat, plan to do so for the life of the tree.
- There are 3 main treatment techniques for EAB. Trunk injection, soil applied systemics, and trunk sprays with a bark penetrant.
- In most cases for trees over 12" in diameter we recommend trunk injection with emamectin benzoate. This provides a 2 year residual.
- For smaller trees, we generally recommend treatment with imidacloprid with our soil injection equipment for proper dosing. For very young trees, trees on a slope, or trees near water we may recommend the trunk spray option.
- With any option, timing is critical to the success of the treatment.
- Our arborists will check on your tree periodically and advise on any other care as needed.
- As with any tree, we want to reduce tree stress through efficient watering, mulching, fertilization, and pruning.