Emerald Ash Borer

The Emerald Ash Borer (EAB) Agrilus planipennis was discovered in the western suburbs of Chicago several years ago and is an immediate threat to ash trees in the Glen Ellyn area. The EAB is a non-native pest first discovered in this country in Michigan 10 years ago. The pest is currently in 14 states and has killed an estimated 100 million trees to date. The entire genus of ash Fraxinus is at risk in North America.

The Village Links of Glen Ellyn has 420 ash trees on the property which is approximately 10% of our golf course tree inventory. While many experts feel it is not possible or too costly to protect ash trees from the EAB, it has been shown that if treatment is started early enough, ash trees can survive the current EAB infestation. The key is to begin treatment before the EAB becomes established in a tree and once treatment begins it needs to continue into the future. We have decided it is worth the expense and effort to protect our ash tree population.

It is important to understand the EAB life cycle if you want to keep it at bay. The adult beetles shown below emerge from an infected tree from mid May until late June. The adult beetle stage of the EAB does not cause any damage. They mate and lay approximately 200 eggs on the bark of a nearby ash tree. The eggs hatch into larvae which burrow through the bark and begin feeding on the tree's cambium layer located between the bark and the wood of the tree. This vascular layer is where water and sap flows from the roots to the tree top. If enough larvae are feeding in this layer, sap will stop flowing and the tree will die. The cambium layer is also the only route an insecticide can travel to kill the EAB larvae. That is why it is so important to begin treatment before a tree is infected. The larvae continue to feed on the cambium layer all summer and fall growing to about 1/2" in length. The EAB over winters in the larval stage, feeds for a short time in the spring, then pupates into the beetle form where it emerges to complete the life cycle.   

 Emerald Ash Borers Adults collected June 27, 2011

So how does the average homeowner decide what steps to take if they have an ash tree. The first step would be to identify the trees on your property to see if you have an ash tree. Remember, the EAB can kill all ash trees so it doesn't matter what type of ash tree you have. 

 This is a typical leaf cluster from an ash tree. Note the leaves join the stem in pairs. Many other trees have single alternating leaves staggered along the stem.

Once you have determined you have an ash tree in your yard you should assess it's over-all health and value in your landscape to help you figure if it's worth the expense and effort to keep your tree(s) protected. Is your tree currently healthy or does it have declining and broken branches? Does it have proper form or is it misshapen due to improper pruning or storm damage? Is the tree a prominent part of your landscape or is it hidden among a cluster of other trees? Is the tree in the proper location or is causing problems because it it too close to your house? If you want to keep the tree, you must take action now and continue treating your tree for the foreseeable future.

 

One of the symptoms of EAB is the formation of branch suckers close to or on the tree trunk. This tree in the Raintree Subdivision shows no other symptoms and may respond to treatment if immediate action is taken.

 This ash tree has been infected for 2 years. The entire interior branching structure has died making it a poor choice to try and save.

 This tree has been infected for 4 years. Only the trunk and a few branches on the right side are still alive.

 

This tree was treated with insecticide but not until it was infected with EAB for 2 years. Sadly, this ash tree will not recover.

Remember, if your tree is already 20% to 40% infected with EAB, it will most likely die even with treatment. There are several treatment options for preventing and controlling EAB. Professional tree care companies have access to insecticides that may be injected into the tree, applied as a bark penetrant or applied as a soil drench. The only EAB insecticide available to a homeowner is Bayer Advanced Tree and Shrub Insect Control. It is important to follow the label instructions when using this product. It is recommended the product be applied in the mid to late spring or in the mid fall period. The product is easy to apply. The insecticide comes in a small water soluble packet which is placed in a 5 gallon bucket of water. The packet quickly dissolves releasing the powder containing the insecticide. Simply stir the product thoroughly and pour around the base of the ash tree. It is best to make the application on a sunny day when there is a moderate amount of moisture in the soil.

For more information on EAB: http://emeraldashborer.info/