The Emerald Ash Borer
The Oleaceae is an important family of trees and shrubs with opposite compound or simple leaves. A few are tropical but most are found in the Northern Hemisphere. Some noted ornamentals are lilacs and forsythia of Asia, privet of the Eastern Hemisphere, the fringe tree, native to southwestern Ohio and jasmine of the tropics and subtropics.
The family also contains the important olive of the eastern Mediterranean and the genus Fraxinus, the ashes.
The ashes are an important component of the eastern deciduous forests of the U.S. They also can be found in other parts of the world. The most important and most common species is the white ash found in every Ohio County. The green ash, a variety of red ash is found throughout Ohio. Varieties of the green ash are important as ornamental plantings. The black ash, a tree of swampy woods, lake shores and valley flats is found over most of Ohio except for some southeastern counties. It is rare in Seneca County. The blue ash is found in western Ohio except for a few central ‘’prairie’’ counties. The young stems are square. The plant is rare in Seneca County.
The ash wood is very strong, elastic, tough, hard, and light in weight. It is easy to split, yet hard to nail. It is light reddish brown and is capable of a high polish. Besides its value as structural timber, its wood is used for handles, oars, barrels, baskets, boats, farm implements, and sometimes furniture and flooring.
Ash trees in general have shown symptoms of decline for 20 to 30 years. Native ash borers (the banded ash borer and the ash/lilac borer) are common pests that particularly attack stressed trees. Their larvae produce large round exit holes and the adults are clearwing moths.
Less than ten years ago, green (emerald) beetles were unloaded in Detroit aboard crates from an Asian freighter. These emerald ash borers quickly spread and killed trees in Wayne and Monroe Counties in Michigan.
As of the date of this writing, 6 million Michigan ash trees have died. Other Michigan counties besides Wayne and Monroe that are severely infested are Washtenaw, Livingston, Lenawee, Oakland and Macomb. These counties were quarantined in July. In addition, the neighboring counties of St. Clair, Lapeer, Genesee, Shawasee, Ingham, Jackson and Lenawee were quarantined in August.
The quarantine means that no wood of any description or from any species can be removed from any property. Firewood is only available to the particular landowner to be used on his property.
In Ohio, the Emerald Ash Borer was found in Lucas County near the town of Whitehouse. A later discovery was near Hicksville in Defiance County. Thousands of trees around Whitehouse have been infested and are being cut down. Plans are made to remove a swath of trees in Hicksville. The beetle has also been sighted in Ontario.
In Michigan, $14 million have already been spent. It is anticipated that over the next dozen years, $354 million will be spent battling the insect. A task force entomologist, Toby Petrice, said, ‘’The emerald ash borer is the most significant pest we’ve dealt with since the Asian long horned beetle.’’ It kills trees much faster, generally in one year, and it spreads more rapidly.
The Ohio State Agriculture Department stated, ‘’The pest has arguably caused the state’s biggest forestry crisis in decades.’’ The beetle has the potential to spread like wildfire and destroy Ohio’s 3.8 billion ash trees.’ ’
The half-inch long emerald beetle lays its tiny, almost microscopic, eggs in the crown of ash trees. The larvae penetrate and burrow into the inner bark, destroying the food conducting tissue (phloem), the functional water conducting tissue (xylem) and the area of rapid cell division. It rapidly moves down the main trunk and emerges through a small D shaped hole, about 3-4 mm broad, and exits as the adult green beetle about May 15.
Early symptoms of the infestation are dying upper branches and leaves, and splitting of the bark above the exit holes. Trees may send out new branches hear the base of the trunk. Woodpeckers, looking for the larvae, move up and down the trunk, even pecking on the smaller branches.
In Michigan, about 50 surveyors are mapping the infestation. Random samples are globally positioned from the air. A team of 2 will come to the center of the chosen spot, move out one half mile from the center of the spot and examine every ash in that square mile.
We own a share of about 60 acres of land in Ingham County, Michigan. Several trees are marked with yellow ribbons as infested with the emerald ash borer. We have been told not to remove any wood from the property.
Ohio residents are encouraged to call the agriculture department’s plant pest section at 614 728-6400.
The plant scientists and entomologists of both Michigan and Ohio are actively engaged in studying the life cycle of the borer and aspects of control. It is going to be a long, hard task.
The Toledo Blade of September 2, 2003 has an article about the borer. The article is entitled “Task Force Hunts for Weapons to Quash Area’s Ash Tree Enemy”. That is the source of some of the information in this report.
– Percy