Emerald Ash Borer

With all the news regarding the Emerald Ash Borer, we are getting many inquiries. Ranging from beetle identification to panic about what to do, we get calls and visits daily regarding this exotic pest. I’ll try to summarize the highlights about this insect.

The Emerald Ash Borer is considered exotic, because it is not native. Since it isn’t native, it doesn’t currently have any natural controls to keep it in check. The frightening aspect of the pest is that it can attack healthy trees. Most other borers attack only stressed trees. The good news is that it doesn’t appear to be a problem in the Peoria area yet.

The Illinois Department of Agriculture has taken aggressive steps to determine the actual status of this pest in our state. 5,000 traps were placed throughout Illinois to determine where the borer is active. The traps are being taken down now, but it will take a couple of months to analyze the large volume of traps.

The insect found in Bloomington appears to be isolated at the moment. They were not able to find an infestation in the area around where the beetle was located. They believe it was brought in from someone who transported the pest in firewood. However, there was an infestation found in Chenoa, IL that appears to have been there for awhile.

What does this mean to homeowners?

1. Don’t bring firewood in from other areas. The borer cannot travel far on its own, so hitching a ride on a load of firewood is the most effective way to transport exotic wood boring insects.
2. The adult EAB is a mall, slender, green beetle that can fit on a penny.
3. The larval stage feeds under the bark of the tree; you won’t see it unless you cut into the tree.
4. The borer is very slow moving unless it is aided by humans.
5. You don’t need to treat your ash yet. The University of Illinois insists there is no need to treat until the insect is verified within 15 miles of your home. Some companies are advertising that you must treat your ash trees now, we do not consider this prudent. First of all, as we mentioned, the EAB is not yet present in Peoria, so chemical treatment is premature.
6. Stressed and weakened trees will most likely be attacked first. Keep your tree healthy for the best control.
7. If the insect becomes numerous, it is then that healthy trees become infected.
8. Once confirmed in your area, the U of I believes you will have adequate time to inoculate your ash tree(s) against the Emerald Ash Borer.
9. Because it is slow to spread, you will most likely to have 2 years to get your tree treated if you choose to, before it might attack your tree.
10. Emerald Ash Borer is not known to attack any other species but ash.
11. When and if you decide on a chemical treatment for your ash trees, you can treat the tree(s) yourself with imidacloprid. It is easy for a homeowner to apply imidacloprid. It is available through several brands such as Fertilome and Bayer. This gives 90% control, which the U of I considers to be excellent control measures.
12. If you are applying the imidacloprid, it requires annual applications. It takes 2 years before older trees are fully inoculated.
13. There is some concern about the affect of imidacloprid on bees. While it is not substantiated, consider whether to use an alternative control when available. Since bees do not pollinate ash, imidacloprid for ash should not be a threat to bees.
14. A tree service can apply Tree-Age. This control can give up to 2 years of control. A homeowner cannot apply this.
15. Ash trees can be subject to many problems. If you have problems on your ash, and the EAB is not in your area, there is likely to be another cause.
16. EAB cannot be detected until it has been in the tree for a few years.
17. Early detection requires destructive measures to the tree. Such methods are reserved for areas where EAB is confirmed.
18. Per the Illinois Department of Agriculture, symptoms of EAB-infestation include decline, crown dye-back, D-shaped exit holes, excess woodpecker damage, basal sprouting, and larval galleries.
19. If, after consultation with a local expert, an EAB infestation is suspected, you should contact the Illinois Department of Agriculture at 1-800-641-3934 or the EAB USDA hotline at 1-800-322-4512.

Eventually, a homeowner may want to consider whether his or her tree is worth the annual cost to treat against EAB. This is a choice the homeowner must make. While we at Hoerr Nursery are no longer selling Ash trees, it is too early to give up on your tree. Perhaps treatment options will improve in the future. Time will tell what action you need to take in your area. For now, keep your eyes and ears open. When conditions or treatment options change significantly, we will keep you updated!

--Dave

Related Links:

Emerald Ash Borer Blog Update

This article is in response to the Emerald Ash Borer post on August 28

I attended the Chenoa Emerald Ash Borer Field Day on September 4, 2008. Experts on EAB from various State of Illinois Agencies provided the most up to date information available. Here are a couple of important points I wanted to add:
 

1. Contrary to advertisements by some tree services, Ash infected with EAB can be saved. To say, "Once an Ash tree is infested with EAB it is too late" is false information. EAB can be controlled in an ash that has been attacked by EAB, even up to 30% of the tree.
2. They reiterated that EAB moves only about 1/2 mile per year on its own. Therefore, the University of Illinois strongly believes that once the borer is found within 15 miles of your ash, you have a real good cushion of 7 years or more to get the tree treated.
3. Treatments against EAB must be done forever, like over a million years. So you will want to weigh the costs of treatment. Many municipalities are opting to remove ash in public areas rather than treat them, due to the cost.
4. Only Ash in the genus Fraxinus are susceptible. Mountainash, which is in the genus Sorbus, is resistant.
5. Damage most likely starts in the top of the tree. Early, D-shaped exit holes will not be noticeable from the ground. Other ash problems can also cause the top of the tree to thin out.
6. The Illinois Department of Agriculture recommends you contact a local expert to identify an insect that you suspect may be Emerald Ash Borer before calling them. You are welcome to bring your sample to Hoerr Nursery for ID.
7. The big purple traps are still hanging around, so it will be awhile before we hear the results for our area.
8. Most EAB have a one year life cycle. For larvae that hatched late, they will have a 2-year life cycle.

For more information about the Emerald Ash Borer, visit: www.IllinoisEAB.com

-Dave

How a tree wants to be treated

Homeowners are continually surprised and well, saddened when I have to tell them the reason their tree is in bad shape is because of something they did that’s causing stress to their tree. Here are some examples:

Improper Planting Depth

When planting, position the top of the container tree or balled and burlapped tree higher than the existing soil level. About 2" higher is ideal. Dig the hole wider than the container, not deeper. Any loosened soil below the root ball will sink in time so backfilling the depth is NOT a good idea. Roots only grow 12” to 24” deep; they need room to grow horizontally. And planting too deep deprives the roots of necessary oxygen – which is a no, no.

Killing a Tree with Kindness

Killing a tree with kindness is pretty common, unfortunately. What I mean is if the leaves of the tree become droopy and discolored, the owner’s think – hmm, you must be thirsty! Keep in mind, it is possible to over-water your trees. What I do is stick a trowel in the soil and wiggle it back and forth about 6” down, to actually see (or feel) the moisture level. If it’s wet…don’t water. If it’s moist…most likely don’t water…if it’s dry…water.

Too Much Mulch

I wish I had a dime for every tree I found with mulch piled up around the trunk like a little volcano. This is bad for the tree. Why? The mulch keeps the trunk wet which promotes rot or decay. It invites little critters such as mice or insects into a haven of mulch while they munch on the trunk and roots. Too much mulch (anything over 4” high) actually changes the oxygen level to the root (yes, tree roots need oxygen just like we do), and the same for the moisture level. At Hoerr Nursery, we recommend keeping the mulch about 6” away from the trunk and use only 2-3” of thickness covering the ground out to the drip line of the tree (if possible). If you could ask the tree how much mulch to use, it would say: “I would like the whole yard covered, please.” Realistically, do what you can and go out as far as you can for the sake and health of the tree. Even a 4ft ring is better than none.

Tree Wrap

Tree wraps are only temporary. Trees trunks photosynthesize along with the leaves - so it’s important not to leave tree wrap on too long. We suggest just for the winter months when sun scald may occur during our cold, sunny days. The temperature on the shady side of the bark is a different temperature than the area that has been warmed up from the south west side. Once a cloud suddenly covers the warm rays and the freezing temperatures quickly chill the once warm part of the trunk, the sap inside explodes (sort of) and the tree gets what we call “frost crack.” Tree wraps help to stabilize the trunk temperature so for this reason, they work. They can be placed on the trunk in October or November and they should be removed in April. If you don’t remove the tree wrap, during the summer months, insects can damage the bark of the tree and you wouldn’t notice it until the wrap is removed – and then it’s too late…

A Very Important Highway

100% of the trunk is used to deliver water and nutrients to the leaves and food to the roots. It’s like a highway where the outer-most bark moves in the downward direction transporting food made from the leaves to the roots. A very important highway. A little farther under the bark is another highway that carries water with nutrients up the trunk from the roots. Another very important highway. Any injury to the trunk means the upward or downward flow is interrupted (sort of like construction work) and the flow gets diverted around the injured area, if possible. Any injury to the trunk can cause dieback to the top of the tree and possibly death over time. A wide ring of mulch helps prevent lawnmower or weed trimmer injury to the trunk. And, contrary to popular opinion….trees do not “heal” themselves. If it’s injured, it dies. It doesn’t come back or work the same again. Not like us when our cells regenerate. These cells die permanently. Think of the roots and the trunk as the lifeline to the tree. The carelessness with equipment is often overlooked because people think trees regenerate and they don’t.

Flower Beds

Lastly, don’t install a cute little flower bed under the canopy of an existing tree. Every root you cut or every inch of soil you add on top of the roots while planting those flowers will affect some part of the tree that it’s connected to. And it is connected to something. You’ve seen your neighbor do this and the tree looks fine. Unfortunately, trees can take several years to show damage that was done. Sometimes it can take up to 7 years for a tree to die from root damage. You won’t remember planting those flowers 7 years earlier. But you will wonder why the tree is not doing well now. This is the same danger from a patio or walk put anywhere near where the tree roots will be affected. Some trees are tougher than others, some not. Try to refrain from doing a lot of digging under the canopy of an existing tree.

The tree thanks you and so do I. :-)

--Marilyn
 

Fall Tree Care Tips

As trees are preparing for their fall color display, you can help them prepare for a long, chilly winter. Follow these fall tree care tips to keep your tree healthy and strong:

• Mulch! Surround your trees with a layer of organic composted mulch to hold in moisture and reduce temperature extremes. Your trees will thank you for it! Apply mulch in late fall after the ground has frozen.

• Get out the pruning saw and remove out dead branches now to prevent issues in the winter.

• Wrap young or newly planted tree trucks with tree-wrap paper to prevent sun-scalding over winter. Wrap in late fall and remove in early spring.

• Evergreens lose water from their foliage all winter, since they keep their needles year-round. Water them thoroughly before the ground freezes, and don’t forget the mulch!

• Diseased leaves can re-infect a tree even if they have fallen to the ground. Remove leaves from around trees as they fall. Healthy leaves make excellent compost and can be shredded and raked over existing garden beds. Diseased leaves, however, should be disposed of rather than composted or burned.

Enjoy the beauty of fall!

Ella

Preparing Young Trees for Winter

Young trees need a little extra protection during the chilly winter months – the trunk is actually the most susceptible to problems. “Sunscald” is when the trunk is actually burned by the sun and can put the tree in danger of developing frost cracks which can harm the tree. No worries! Applying tree wrap is a quick, easy and inexpensive method to protect your tree investment this winter.

Installing Tree Wrap
• First, pick up a tree wrap product at the Garden Center. Begin by wrapping the base of the trunk and working your way upward, overlapping the wrap as you go. This allows the wrap to shed water away from the trunk and prevent water from running down the inside of the tree wrap.

• Continue to wrap tightly until you reach the first horizontal branch. Cut the wrap and secure with twine at the top. Avoid using nylon twine or wire.

• When spring arrives and warm temperatures return, carefully remove the tree wrap. Don't forget! Leaving it on during the warmer months can provide a habitat for harmful insects.

Protection from Animals
Trees are also susceptible to harm from rodents, rabbits, and deer throughout the winter. To prevent problems from small animals, be sure to wrap young trees tightly. Deer love to rub their antlers on the trunks of small trees, so create a barrier of chicken wire around the trunk, and secure it to T-posts in the ground at a height of 3 to 4 feet.

Liquid Fence
For a little extra help, apply a chemical repellant called Liquid Fence to your young trees. This liquid spray can be applied all winter when the temperatures are above freezing, and it will guard the tree against animals.

Take a little extra care to tuck your young trees in for the winter, and they will thank you for it in the spring!

Ella