Volume 15, Issue 4 ~ January 25 - January 31, 2007

Invasion of the Emerald Ash Borer

Richard Feeney stands with felled ash trees waiting to be chipped to destroy any emerald ash borer larvae within the wood.

Fighting the half-inch eco-terrorists costs millions

by Sandra Olivetti Martin

The whole world, so the saying goes, feels the ripples of a butterfly’s wing beating in the Amazon basin.

Here in Maryland, the secret gnawing of the tiny, segmented larvae of the emerald ash borer has mobilized well over 100 plant soldiers in a multi-million dollar, chop-and-chip war. Unless they win, the damage nationwide could rise as high as $60 billion, leaving America barren of the ash trees that shade our streets and shape our baseball bats.

“This insect pest is fatal to ash trees,” says Carol Holko, chief of the Maryland Department of Agriculture’s plant protection program. “If we don’t stop it at Prince George’s County, it can move into the rest of Maryland and the East Coast.”

Distant Ripples

Like that distant butterfly, Agrilus planipennis made its first unnoticed move far from Clinton and Brandywine, where even as you read Maryland fights its war of eradication. The mysteries of its passage rippled outward something like this:

Somewhere in China, the insect we call emerald ash borer chiseled itself a home in a tree. It laid eggs, and the eggs developed into larvae. The tree was chopped down, sawed into lumber and cobbled into a pallet. China, manufacturer for the world in the 21st century global economy, stacked trade goods on that pallet. The pallet was loaded onto a ship that crossed the ocean. Stowed away in the pallet, the insect terrorist penetrated into the heart of America.

Likely it came by way of the Great Lakes, for four contiguous Midwestern states, three of them Great Lakes states — Michigan, Illinois, Indiana and Ohio — were, by 2003, infested with the half-inch-long emerald ash borer. By now, the green bug has cost those states 25 million ash trees.

That same year, it jumped cross-country to Maryland.

Among the many mysteries surrounding the emerald ash borer’s 21st century invasion of America is how much we know about its entry into Maryland.

“We know exactly when and where,” says Maryland Department of Agriculture spokeswoman Sue duPont.

In 2002, the ash borer had been identified in Michigan and all ash — living or dead wood — from that state quarantined. But in April of 2003, a scofflaw Michigan nurseryman filled an unsuspecting Maryland nursery’s order for ash trees. With those 121 trees, the ash borer rippled into Maryland.

Its invasion was secret until the following August, when a sharp-eyed Maryland plant inspector, alert to the creature’s presence in the Midwest, noticed that the ash trees on the back lot of Ed’s Plant World in Brandywine didn’t look healthy.

The D-shaped holes she found in their bark confirmed her worst fears.

You’re not going to like what I’m seeing, she reported back to state ag headquarters on Harry Truman Parkway in Annapolis.

“Since then, we’ve seen a lot more than we’d like,” says Holko. “It’s one of the biggest things to happen here.”


Ag, Natural Resources and P.G. soldiers scrambled. Since adult beetles emerge in the spring, by August not only the original 121 Michigan trees but every tree that had been on the lot was a potential time bomb. Every ash tree sold at Ed’s had to be tracked. Following sales receipts, the team drew as its campaign a mile-wide circle encompassing all those trees.

“They were all close to the shipped-in area, so we were still working in a very defined area,” said duPont, who noted that nearby neighborhood trees were also infested.

The containment circle of about 500 acres doubled the half-mile the borer can travel per emergence. Within that circle, 11,000 trees — from whips to saplings to stately street and forest giants — were felled, since no insecticide is 100 percent effective against the borer. Then the wood was examined and double-chipped so that no piece was larger than one inch in two dimensions. Such small chips prevent both larvae and adults from surviving and reward contractors with sellable mulch.

Not only is the ash borer mobile, the ash — with its fronds of helicopter seeds — is a prolific tree. But most mobile of all are people, who can carry the borer hundreds and thousands of miles on infested wood. All of Prince George’s County, including wood sellers, went under ash quarantine.

Then, each spring for three years, sentinel trees were planted in spots where infected trees had been found. Each fall they were cut and their bark peeled so inspectors could hunt for the spiral track of the larvae that gird and kill. None appeared.

By the end of 2005, the war seemed won.


Last August, the telltale D-shaped exit holes showed up again.

They’re still here, the weary soldiers said — and started all over again.

Now, three years into the Maryland invasion, the circle of containment has spread to two miles.

As we go to press, more than 3,400 trees have been cut; more than 60 percent are small trees, no larger than 10 inches in diameter. As the number grows every day, the chip pile at Cheltenham rises.

So far, fighting this invading bug has cost taxpayers $2 million in federal and state money; winning will cost at least that much more. If the borer gets past the P.G. army, there’s no stopping it — or containing the costs of the escalating war.

And we’ve only got until March 31, when the next generation crawls out to go mating.

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