Horticulture News: Emerald Ash Borer seems here to stay

By Kim Cowherd, Published:

The Emerald Ash Borer (EAB) is here to stay in Franklin County. We have a sound plan for living with this small insect that is based upon research findings and experiences from older infestations in other states. The challenge is to do everything we can to make the plan work and learn to manage the EAB.

EAB adults are 3/8 to 3/4-inch long and very narrow (about 1/5-inch wide). The head is blunt, the body tapers noticeably at the end of the abdomen. The wing covers are emerald green; the top of the abdomen, visible when the wings are spread, is metallic purple-red.

Adult emerald ash borers are active in mid-spring to early summer. The flying adult begins to die off after about six weeks or so. Individual adults live for about three weeks but emergence occurs over several weeks so the activity period in Kentucky may extend from early May to late June or beyond.

What trees does the EAB attack?

All species of ash (Fraxinus) in landscapes, forests, and woodlots in eastern North America are susceptible. Adult females can lay eggs on stressed trees, but healthy ones also can be infested. Tree size does not appear to make a difference either; larval (immature stage) tunnels under the bark have been found in trees or branches as small as one inch in diameter.

How does the EAB damage your Ash tree?

As they feed under the bark, EAB larvae destroy the tree’s water and nutrient conducting tissue. This reduces water and nutrient flow to the top of the tree and causes thinning. Dieback in heavily infested trees usually starts at the top with one-third to one-half of the branches dying in one year; most of the canopy will die within two years of the first appearance of symptoms.

This heavily thinning canopy is the stage of infestation we find ourselves in Franklin County. Discussions with several UK Extension Entomologists, ISA Certified Arborists and professional horticulturists in the county found us all noticing significant thinning and dead limbs in many of our local ash tree canopies in 2012. These trees are located in subdivisions, woods, parks and lining streets all across our county.

The next thing we also noted, the ashes that have been treated according to research-based, recommended practices, are appearing to be much healthier, with little to no loss of foliage. The age of the tree or location in the county didn’t matter.

What can homeowners and property owners do for their ash trees?

You can contact a certified, licensed arborist who is knowledgeable and trained in specific insecticide treatments. Or contact the Extension Office for information on ISA Certified Arborists in our area, information on EAB and reliable home treatments.

While it is no longer necessary to call in experts to positively identify the EAB presence, since we know it is here, you can obtain information that can help you make decisions in managing your ash trees.

Some ash trees that haven’t yet started to be treated, may not yet be infected. If the owner decides to keep the tree, treatments will need to be started soon in order to have the best chance of survival.

If the tree has some characteristic EAB signs, but is mostly fully leafed out, those should also begin treatments to try to stop any further potential damage by EAB. However, if your ash tree appears dead except for possible small sprouts coming off the trunk or from the base of the tree, or no leaves are on the tree at all, or most of the bark is falling off, then there is very little that can be done to save the tree.

Homeowners can purchase and apply products to their trees containing the active ingredient Imidacloprid. This chemical is mixed with water and poured at the base of the tree’s trunk. Be sure that you read and follow all directions with chemical applications and be sure the product you purchase states it can be used on Ash trees for Emerald Ash Borer insects.

This insecticide is best when used in mid-fall or mid- to late spring and on trees that are less than 15-inch in diameter at breast height (DBH). Larger trees need different chemicals and application methods that are only available to certified pesticide applicators.

Do be aware that there are many other problems, including diseases, insects and general maintenance practices that can affect the health of Ash trees, not just the Emerald Ash Borer. Also remember that EAB only attacks ash trees.

So be aware and be informed!

For more information on EAB control, log on to http://pest.ca.uky.edu/EXT/EAB/EABcontrol.pdf or contact the Extension office for a printed copy. For additional information on EAB check http://bit.ly/13bwTxY or http://pest.ca.uky.edu/EXT/EAB/welcome.html, or contact the Extension Office to obtain printed copies of Emerald Ash Borer information.

Contact the Franklin County Extension Office if you have questions at 695-9035 or would like printed information or email DL_CES_Franklin@Email.UKY.EDU.

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  • "EAB SEEMS HERE TO STAY" SOUNDS MISLEADING! Unlike Dutch Elm Disease that lets trees reach seeding age of 10-15 years old before it kills them, EAB kills Ash at a way younger age when they reach 1"DBH or 3" Circumference in trunk size. Not one solitary young Ash reached seeding age of ten years old in Michigan forests that succumbed to the Borer 12 years after EAB's arrival in them. Also, Soil in these forests were void of Ash seeds capable of germinating new trees. WELCOME TO THE MODERN DAY EXTINCTION EVENT OF THE AMERICAN ASH TREE. The Fraxinus Ash species evolved on our continent, and spread all over the northern hemisphere of our planet during Geopoetry events. By collecting seeds of native Ash trees which contain locally evolved DNA from each specific neighborhood forest, Scientists can plant new trees from them once EAB glutinously kills off it's only food source of untreated ash. ANY COMMUNITY THAT IS OVER A CENTURY OLD WILL STILL HAVE ASH TREES GROWING THAT WERE PLANTED BY THEIR FIRST SETTLERS & EARLY RESIDENTS. These 120 year old "Roman column" postured trees are still only teenagers with lifespans of Green Ash 300 & White Ash 6OO years in front of them. Generic Imidacloprid 75WSB(% Water soluble bag) purchased over tree stuff internet for $35 is enough to treat one 40 year old tree for 2 or 3 years. Use Government approved 2.80 gram dose per DBH! Apply Mid April to end of May. Dig moat around root flair & pour it or soil inject past the grass no deeper than 4" for Ash. Municipalities that bulk purchase this stuff can spend $5 per tree or $30 total over six years doing it themselves in-house until EAB's population inevitably crashes. Good luck from Chicago...