Garden Guidance
A Love Affair Made in the Far East
By John H.Weis, MSU Extension Advanced Master Gardener Volunteer

By now, most have heard that we have a new arrival.  This critter came into our state sometime around 1992.  It came without being invited, probably in some cargo into the Detroit metropolitan area, and it doesn’t want to leave.  This critter is called the Emerald Ash Borer (EAB for short).  The love affair has to do with the Ash Tree and all species of ash in our state.  Of some note is the fact that this borer, while not the only borer in Michigan, particularly likes the scent and the inner sapwood of this tree, now endangered in our state.  In China, this borer is not considered a serious threat, but when American Ash Trees were introduced into their nursery stock, it was love at first bite.  This insect pest is slowly but surely extending its range; it was recently identified in Sleeper State Park in the Thumb and Brimley State Park in Chippewa County in the Upper Peninsula.

It is easily confused with other pests, such as the Japanese beetle, which is metallic green with brown wings.  This beetle has a rounder, more robust body type than the Ash borer, which is decidedly metallic green with a bullet shaped body that tails off at the end.  EAB’s head is greenish-brown.  There are other look-a-likes such as the tiger beetle, which has longer antennae and longer legs and is hairy underneath.  The ash borer has very short antennae.  Other insects that have metallic green are the June beetles with a wide robust body; the Fiery Searcher with dark greenish gold on the sides of its head; and the Green Pubescent ground beetle with bright green above and black below, so check the bottom.  Most ground beetles are considered beneficial insects, so be kind to them.

Now, just how did the ash borer get this far if its annual range is only about ½ mile?  State parks are particularly vulnerable, as campers bring firewood into the area.  The track of this pest, while concentrated in the southeastern portion of our state, can also be traced along I-75 north.  Obviously, this pest is hitching a ride to an area near you.  Since the larvae live in the sap wood, cutting into logs has no effect; it only transports the pest in manageable log sizes.  Transporting ash firewood now comes with a hefty fine.  And, while some may not have gotten the word, and others may not be concerned one way or the other, it is also possible that some campers may not be able to identify an ash tree. 

Once you identify an ash tree, it is not easy to spot an Emerald Ash Borer.  This is because it tends to feed at the top of the tree in mid-May before descending to lay its eggs, up to 90 in a season.  It prefers the upper branches because it enjoys the warmth and the sunlight.  Eggs are laid in tree crevices and an indicator of their presence is often woodpecker markings which peel away some of the outer bark.  The EAB life cycle is depicted as follows: 1) Eggs hatch into larvae and tunnel into tree - May to August, 2) Larvae feed under bark, creating S-shaped galleries – August to October, 3) Adults emerge leaving D-shaped exit holes - May to June, and 4) Adults lay eggs on ash bark -mid-May to mid-August.  Then the cycle begins again.

There are some chemical controls available, some are “restricted use chemicals” requiring a licensed arborist, but there are other controls available to homeowners.  There is a soil drench that uses a product called Bayer Advanced Garden Tree and Shrub Control ®, with the active ingredient IMIDACLOPID.  This should be applied from April to early May.  Another product is Bayer Advanced Garden Multi-Insect Killer ® for use in early June and again in early July.  The active ingredient is CYFLUTHRIN; it is a trunk and foliage spray.  To be effective, homeowners must get good coverage of trunk and foliage up and down the tree.  For most people, this is practical only for small trees unless they have access to a cherry picker-type machine.  Then there is ACECAP 97, with the active ingredient ACEPHATE.  This involves systemic tree implants and may take several weeks for the vascular system of the tree to uptake the chemical for it to have any effect.  As with all these products, following label directions thoroughly is very important, and even then, there are many variables and no total guarantees.

Note also that these products are toxic to bees and other beneficial insects that attack pest bugs.

Look carefully in making any preliminary diagnoses.  But, if you see a metallic insect about ½-inch in length, call!

Be assured that much is being done to identify active areas of infestation.  USDA, Department of Natural Resources, and Michigan State University Extension can provide additional information and brochures.  You may have to contact more than one agency as staff is limited and in some cases, volunteers may take your inquiry.  Now that you are now better informed, let us all be on the lookout and lend a hand.

Master Gardener Coming Events in 2006:

• January 16 - March 27 - Master Gardener Series, a joint series Huron and Tuscola Counties, Detroit Edison Building, Cass City, 6:30 - 10:00 PM
• March 25 - Spring Into Gardening Conference, Ubly Heights Country Club
• May 13 - Perennial Plant Sale, Huron Expo Center, Fairgrounds, Bad Axe

Anyone wanting more information on any of these events or on the Emerald Ash Borer is encouraged to call the MSU Extension office in Huron County, 989-269-9949.