Officially, the emerald ash borer arrived in Cumberland County this year. It is likely to be present in Harrisburg as well.
This is a terrible situation for Pennsylvania’s 3,000,000 ash trees. Many of them are in our parks and yards.
The latest imported killer bug, the emerald ash borer, is fast spreading, has no natural U.S. enemies, and can decimate large, healthy ash trees in as little as 2 to 4 years.
According to foresters, arborists, and bug experts, this borer could cause ash to be as devastating as the disease that nearly decimated American chestnuts or American elms.
Ironically, many communities have planted ash trees after the elms had died.
What’s the bug? What is the origin of this bug?
The adult emerald ash borer is about the same size as a housefly.
It is a native of Asia, and it made its way to the United States in wooden packing material.
It was first discovered in Michigan in 2002. Since then, it has been found in at least ten other states. Since 2007, it has been moving east from Allegheny County.
What harm does it cause?
The bark of ash trees is where adult females lay eggs. The caterpillar-like, skinny, white larvae hatch into tiny caterpillars and feed on the wood’s water- and nutrients-moving cells.
This causes the death of the branches, most often near the top. The whole tree usually falls within a year. This leaves you with a hazardous tree that can fail at any moment.
If there is any good news, Emerald Ash Borers only attack ash (genus Fraxinus) and not maples or oaks.
What should I worry about?
There is a good chance that the borers will eventually find all ash trees. They will kill your tree if they see it.
Sven-Erik Spichiger is the state Department of Agriculture’s entomology program manager. He says that forest ash poses a more significant threat. He says that forest ash could wipe out the entire genus.
About 6 per cent of U.S. forests are made up of ash species. They account for $20 billion of the U.S. economy. These include logging (furniture and tools), the nursery, landscaping, and other industries.
What should you do?
“Job No. Hampden Twp. says that one is to find out if what you have is ash. Bob Carey is an arborist and host of “Garden Talk”, a Sunday-morning radio program on WIOO AM 1000.
He said that people, even professionals, often confuse ash with European mountain Ash (not a true one), box elders, and walnuts.
Carey states, “The next step is to figure out how much it will cost to treat it and decide if it’s worth it.” You don’t have to lose a tree you value and is an integral part of your landscape.
It’s possible to wait until the damage is apparent before doing anything. Preventive insecticides must be applied at the time larvae start to feed.
Spichiger states that a tree can usually be saved and treated up to 30% of its canopy. It’s often futile after that.
What is the treatment?
Homeowners can only use one insecticide. The active ingredient is imidacloprid, a brand-name Merit. It’s mixed with water and poured onto the soil around the trunk.
Spring is the best time to apply. The recommended frequency is one treatment per year. The size of the tree will determine the dosage. Treating a mid-sized tree will cost you about $30 per year.
Tree professionals have access to other insecticides that can be injected into trees or applied to bark. Emamectin lasts for two years and is the most commonly used. For a mid-sized tree, expect to pay $125 for treatment.
How do I decide what I should treat?
Greg Hoover, Penn State entomologist, says that trees should be valued and added to the landscape. Then, treatment is justified. If they are smaller, you can quickly remove them and then grind them into less than half-inch pieces to prevent Emerald Ash borer from emerging.
Spichiger adds, “Once you begin treating,” “you’re bound to do it every two years for the lifetime of the tree.”
This means that you can’t treat it once and then forget about it.
However, if you do nothing, the tree will die.
Is there anything else I can do?
“The No. Spichiger says that the No. 1 rule is to not transport wood from one place to another.
The borer can spread by moving firewood and nursery stock from infested areas. Pennsylvania’s 43 western and central counties are currently under quarantine. This bans the movement of ash or similar hardwoods from quarantined areas.
Watch out for signs of borer infestation in your ash.
The most common is branch dieback, but other signs could include bark splitting, new growth coming out of the trunk, and increased woodpecker activity.
The tree bark’s D-shaped exit holes that the borers create are a telltale sign. They are about the same size as a pencil eraser.
If you think of planting an ash tree new, you might consider another species.