The Emerald Ash Borer is well-entrenched in Indiana. This exotic pest has the potential over time to kill all the ash trees in Hidden Valley, significantly altering our environment and property values. Since its discovery in the Detroit, MI area in 2002, the spread of the destructive beetle has been relentless. As of this writing, it is confirmed present in at least six states – MI, OH, IN, IL, PA and WV. Neighboring Hamilton County in Ohio is one of those areas already afflicted. Currently, the mortality rate for untreated infested ash trees is 100%.
The good news is, promising research continues for developing ways to arrest the spread of EAB, and eventually control it. In 2007, native parasitoid wasps (who lay their eggs in beetle larvae) were found attacking EAB larvae near Fenton, Michigan. Further investigation is ongoing to determine if this wasp will become an important natural enemy of EAB.
Options for controlling EAB or protecting high value ash trees in landscapes are another area of interest. In 2007, studies were begun to evaluate a relatively new product called emamectin benzoate. This insecticide is applied via tree trunk injection. Compared to untreated trees, the emamectin benzoate controlled more than 90 percent of the EAB and had a two-year residual effect. State regulatory officials are considering special registration for this product, perhaps as early as spring of 2008.
Is There Anything We Can Do?
While better methods of detecting Emerald Ash Borer are being developed, and more effective means of controlling and eradicating it may be on the horizon, it is unknown whether these discoveries will be perfected in time to save the ash trees in Hidden Valley Lake. It may be years before EAB becomes an issue here. On the other hand, although EAB has not been confirmed in Dearborn County as of this writing, it is commonly present for many years before detection. For this reason it would be a good idea to begin thinking about options for your ash trees. Developing a strategy now for managing EAB will help homeowners meet the pest head-on. You may want to consult a tree care professional (certified arborist) for assistance in making decisions about protecting your ash trees.
For much more information about the Emerald Ash Borer, including how to identify ash trees, please read the article on the HVL website (on the Streets & Parks page under the Committees tab). Informational materials are also available in the POA office.
Homeowners’ EAB Plan
1) Identify - The first step in making an EAB plan is to identify the ash trees on your property. Refer to the article mentioned above for photos of ash tree
characteristics. Although ash trees may not leaf out until late spring, you can identify them in winter by their distinctive bark and their branching pattern.
2) Survey - Draw a simple plot plan, marking the size* and condition of each tree and its position in your yard. The trees’ condition will be easier to determine once leaf-out has occurred.
3) Evaluate – Prioritize the value of your ash trees based on health, location, size and impact on the landscape. Consider the costs of treatment, removal or replacement versus the benefits to you as the homeowner. Keep in mind that the larger the tree, the more costly and perhaps less effective treatment will be. Until better insecticides are developed, treatment will be required on a yearly basis for an indefinite period. The insecticide products marketed for homeowners’ use work best as preventive treatments for healthy ash trees in yard settings. It is rarely practical to treat woodlot trees with insecticides.
Homeowners’ Choices
1) Do nothing - If you choose to do nothing, the tree will be susceptible to EAB attack. Once infested, ash trees will die over the course of a few years. Dead ash trees become brittle, drying out within 1-3 years, and are especially prone to falling. Consider the liability aspects of such an occurrence, based on the location of the tree. Also keep in mind that removal cost is greater for dead trees. Dead ash trees in a woodlot setting however, may not present any problem.
2) Remove preemptively - Ash trees that are in poor condition, regardless of the cause, are not good candidates for EAB control and should probably be removed or replaced. This can be done before or after EAB attacks. If an ash tree is in a poor location, or could be hazardous when dead, preemptive removal may be the best choice. Getting estimates on removal costs now will allow you to work the expense into your budget over a period of time.
3) Treat with insecticides - Once you have evaluated the ash tree situation in your yard, you can make an informed decision on whether to treat valuable trees with a homeowners’ product or have them treated professionally. Although there is evidence that use of pesticides can salvage some ash trees in early stages of EAB infestation, prevention is a more reliable strategy. The recommended treatment at this time is imidacloprid, available at garden centers as a soil drench called Bayer Advanced™ Garden Tree and Shrub Insect Control. One 32 oz. bottle costs about $30 and will treat a tree approximately 32” in circumference (see measuring notes below). The same chemical (by the trade name of Merit) can be applied professionally by several methods, including by soil injection or trunk injection. Whether you choose to treat your ash trees yourself with a homeowner-applied product or a use a professional certified arborist, treatments for EAB are best applied between mid-April and mid-May. In our area, mid-April is preferable.
4) Plant a new tree – If you plan to remove an ash tree, consider planting a new tree of a suitable variety in its place. In HVL however, be prepared to protect new trees with fencing and repellants against damage from deer.
Responsible Citizenship
Your EAB management plan should note any ash trees that may do serious damage to your or your neighbors’ property should they die and fall. Consider either treating potentially dangerous ash trees as a preventative measure (if practical) or removing them preemptively before EAB invades.
Please be responsible with any chemical treatment that may leach into any of our lakes. Check the label or ask the arborist if it is safe. The chemical mentioned above is toxic to aquatic invertebrates and should not be used when there is a chance it will flow into lakes, streams or ponds. Nor should leftover chemical solution or rinse water be dumped into sewers or other bodies of water. If the trees you wish to treat are near a lake, trunk injections may be a more appropriate treatment method than soil drenches or injections.
Residents should also be aware of the federal order that prohibits the interstate movement of regulated articles that originate within the quarantine area (MI, OH, IN, IL). Ash nursery stock and green lumber, any other ash material including logs, firewood, stumps, roots, branches, as well as composted and un-composted wood chips may not be transported across state lines. Due to the difficulty in distinguishing between species of hardwood firewood, all hardwood firewood, including ash, oak, maple and hickory are regulated by the state and federal quarantines regulating the movement of ash products.
As the Emerald Ash Borer continues its relentless approach, there may not be much we can do to prevent infestation from occurring. But homeowners can educate themselves in preparation for its arrival. Research suggests that the best control will be obtained when treatments are initiated in the earliest stages of infestation before visible symptoms are present, or perhaps even the year before trees are infested. To be prepared, act now - survey your lot, weigh your options, and make informed decisions.
*Tree size is usually measured with calipers as the diameter at breast height (dbh), about 5’ from the ground. Some insecticides will specify the distance around the trunk or circumference, measured with a flexible measuring tape. Follow label instructions carefully. To convert, circumference = 3.14 x diameter. Or, diameter = circumference divided by 3.14.
What is EAB?
The Emerald Ash Borer (EAB) is a bright metallic green beetle. Adults are one third inch long and one sixteenth inch wide with rounded abdomens and flat backs. Though tiny, this exotic pest has destroyed over 20 million ash trees in Michigan, Ohio and Indiana since 2002. It continues to spread into Maryland, Pennsylvania and Illinois.
Where did it come from?
Emerald Ash Borer hitched a ride from its native Asia to Michigan, probably in wood packing material. Arriving sometime in the 1990s, it was first discovered in the Detroit area in 2002. Even though the insect only flies about ½ mile in a season, it has spread artificially through human transportation of infested firewood, logs or nursery stock. Asian ash trees, having evolved with the beetle, have developed defenses against it. American ash trees have none. Preventive measures such as quarantines and mass cutting of ash trees have not been very effective in stopping its advance. EAB has already been confirmed in 14 counties in Indiana and 31 in OH (including neighboring Hamilton County). It has not yet been verified in Dearborn County.
What does it do to ash trees?
EAB attacks only ash trees, all varieties. About mid-May, adults emerge, leaving small D-shaped exit holes in the bark. They will continue to emerge, mate and lay eggs through late summer. The adults eat foliage but do not harm the tree. The damage is done by the larvae, which form serpentine burrows just under the bark of the tree, eventually girdling it. This disrupts the flow of water and nutrients to the upper branches, ultimately killing the tree. Once infested with EAB, untreated ash trees will die within roughly 2-5 years (100% mortality rate).
Emerald ash borer has killed trees of various size and condition. Stress likely contributes to the vulnerability and rapid decline of infested ash trees. However, EAB has killed apparently vigorous trees in woodlots and urban trees that are regularly irrigated and fertilized.
What do ash trees look like?
About 6% of Indiana forests are ash trees. White ash and green ash are the most commonly found varieties in our area. T he following criteria may be used to identify ash trees:
 A |
 1B |
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 C |
 1D |
 2D |
E
A - Opposite branching: Branches and buds are directly across from each other and not staggered. Keeping in mind that buds or limbs may have been pruned or died, not every single branch will have an opposite mate.
B - Feather-like leaves: Leaves are compound, 8 - 12” long, and composed of 5-11 leaflets. Leaflet edges may be smooth or toothed.
C - Buds: White ash buds are paired, with a leaf scar beneath the bud that looks like the letter “C” turned on its side. Green ash buds have a leaf scar beneath the bud that looks like the letter “D” turned on its side (like a smile).
It can be easy to confuse ash trees with black walnut, which is also common in this area. Leaves of the latter are compound with 9 to 15 leaflets, but the tree has alternating branches. It bears large dark brown nuts inside a green husk.
D - Diamond pattern furrowed bark: On mature trees, the bark is tight with a distinct pattern of diamond-shaped ridges. On young trees, the bark is relatively smooth.
E - Flat, oblong seeds: When seeds are present, they are dry and oar-shaped, usually occurring in clusters. They typically hang on the tree until late fall, early winter.
What can I do to save my ash trees?
Research is being conducted at universities to understand the beetle's life cycle and find ways to detect new infestations, control EAB adults and larvae, and contain the infestation. Currently, there are a few treatments available for ash trees:
Costs involved depend on whether the treatment can be applied by the homeowner or require professional application. In general, the larger the tree, the more costly (and less feasible) the treatment will be.
What happens to the dead ash trees?
Dead ash trees become extremely brittle and will fall. In Indiana, decisions and financial responsibilities regarding ash trees rest solely with property owners. Check with your insurance company regarding liability for damage done by falling trees. Options for disposal include:
Where can I get more information about EAB?
There are comprehensive web sites dedicated to EAB from both the Indiana Dept. of Natural Resources (INDNR) and Purdue University Dept. of Entomology:
www.in.gov/dnr/entomolo/pestinfo/ashborer.htm
A multi-state information center can be found at:
IN Dept. of Natural Resources (DNR) hotline: 800-866-NOEXOTIC
Purdue Ext. list of certified arborists: 888-EXT INFO
This article was compiled by HVL Streets and Parks Committee with information obtained from the Internet and media reports. The intent is to inform property owners about EAB before it is confirmed in our county. The HVL Streets and Parks Committee, Community Manager and POA Board are working diligently to develop strategies and solutions to the problems property owners may be facing in the next few years.
2B