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SUGAR RIDGE, Ohio — Bob Getz has been farming in Wood County for more than 60 years. Over the decades, he has confronted drought, floods, frost, an array of noxious weeds, and a murderer’s row of blights, bacteria, fungi, and insects. But eventually he prevailed against all those foes, and the crops came in.
Now, Mr. Getz is on the front lines in a battle he knows he has lost and part of a war we are certainly losing, against one of the most destructive pests in North America.
Just a half-inch long and jacketed in a metallic green that makes it look more like a cartoon character than killer, the emerald ash borer has wiped out more than 100 trees on the 15 acres near here where Mr. Getz’s home and barns are still surrounded by majestic 150-year-old oaks and a few large maples and elms.
“We’ve lost them all,” he said about the ash trees the borer had eradicated on his property. “We tried to save them by putting this treatment around the base and then washing it into the soil, but it didn’t do a nickel’s worth of good. The borer killed every one of them.”
Most of the ash trees Mr. Getz lost were mature — a couple feet wide at the base and maybe 70 feet tall — but the most painful fatality involved a huge ash on the south side of his woodlot. It is now just a bleached-out skeleton, surrounded by fully leafed-out healthy oaks.
“I’m just sick over losing that big one, because it has to be around a hundred years old,” he said. “It was so healthy and so full every year. I wanted to see it keep growing.”
The trees the Getz farm lost make up just a tiny portion of the ash borer’s hit list. Over the last decade, this pest has killed so many ash trees in 19 states and two Canadian provinces, the experts stopped counting several years ago.
“With the ash borer being so widespread, there is just no way to come up with an accurate estimate on the number of trees we’ve lost. We just can’t put a number on it,” said Brett Gates of the Ohio Department of Agriculture’s emerald ash-borer monitoring program.
Toll in trees
Recent estimates have put Ohio’s ash tree count at more than 3.8 billion, and the borer has been confirmed present in 65 of the state’s 88 counties. Michigan has an estimated 700 million ash trees, and the entire Lower Peninsula is now under quarantine for the ash borer, along with about half the Upper Peninsula and Isle Royale.
“We’ve never been able to do an actual count on how many trees have been lost in the state, but it’s easily in the tens of millions,” said Robin Usborne, communications manager for Michigan State University’s emerald ash borer program. “It has the potential to kill every ash tree in North America.”
The ash borer was first detected in 2002 in the Detroit area. Biologists believe the larvae of the borer hitched a ride here from its native Asia hidden in the wood packing material on a cargo ship. In Asia, the ash trees have evolved alongside the borer and those trees likely have some mechanism of defense against the pest.
Here, the ash borer found no such resistance.
How they destroy
The adult beetles chew on the leaves of the ash trees but do little significant damage. After mating, they lay their eggs in clusters on the bark from May to September. The larvae hatch in about 10 days and then bore through the bark and into the soft, cambial tissue, which is the tree’s life-giving vascular system.
The larvae cut serpentine tunnels while feeding through the winter months. The movement of water and nutrients from the roots to the branches is disrupted and the tree plunges into a death spiral, with the first sign usually being bare branches in the crown.
As the weather warms in the spring, the larvae transform into adult beetles. Usually in late May, these new beetles bore a D-shaped exit hole in the bark and emerge from the tree. The adult beetles live for just a month but quickly start the process over by again attacking the host tree, flying on to the next victim, or getting transported in ash materials by humans, enabling it to infest more areas.
It usually takes two to five years for the ash borer to kill what had been a healthy ash tree. As the ash borer quickly spread from its ground-zero entry point in metro Detroit, quarantine areas were established, but the bug kept jumping those fire lines. It is now in at least 19 states and the Canadian provinces of Ontario and Quebec, with its rapid spread no doubt aided by the movement of firewood and landscape material that hid borer larvae.
The ash borer first surfaced in Ohio near Whitehouse in February, 2003. That is about the same time a forestry inspector for the city of Toledo found evidence of an infestation near Ottawa Park. By 2010, the borer or the threat it presented had claimed 8,000 ash trees in Toledo’s parks and boulevards.
“They’re all gone,” said Denny Garvin, Toledo’s commissioner of parks, recreation, and forestry. “It’s sad to see what it’s done to some of Toledo’s oldest neighborhoods. With all of those dead trees, they looked like ghost towns.”
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The city, the nation, and the continent have experienced extensive species-specific tree losses.
The American chestnut was once the most common tree in the eastern United States, but a blight early in the 20th century nearly wiped it out. Millions of elm trees were lost to a different fungal disease, starting in about 1930.
Ash trees became a popular replacement because they were easy to raise and thrived in a variety of soils. They often grow straight and produce a full, even canopy. But streets and parks lined with the attractive shade of ash trees eventually became the home of gauntlets of bare stick figures.
“We’re not going to make that mistake again,” Mr. Garvin said about using predominantly one species to landscape common areas.
Some experts believe that unlike the chestnuts and elms, which had pockets of isolated survivors when hit with a devastating blight, the ash trees could suffer a worse fate.
“Where these borers have been present the longest, it has basically been a total wipeout," said Mark Widrlechner, an assistant professor of horticulture and agronomy at Iowa State University and a research horticulturist for the U.S. Department of Agriculture, in an issue of Science Daily. “That is something we rarely see in nature.”
On the move
The ash borer is confirmed in 34 counties in Pennsylvania as of May, 2013, according to Houping Liu, the forest entomologist and resident expert on the emerald ash borer for the state’s Bureau of Forestry in the Department of Conservation and Natural Resources. The infested areas cover most of the western two-thirds of the state, with the exception of a thin band of counties along the northern border with New York. There is also an outbreak in Bucks County, northeast of Philadelphia.
Mr. Liu said the state has no estimate of the number of trees that have been lost to the ash borer or of the economic impact as a result of the cleanup and removal of infected trees, the lost dollar value of those trees (some diseased ash can be used for lumber), and the cost for cities and municipalities to replace dead ash trees. He added that Pennsylvania has a “relatively low” ash component compared to Ohio and Michigan, where the postborer costs are yet to be tallied.
“We don’t have an exact estimate on what this all will cost,” said Mr. Gates of the Ohio Department of Agriculture, “because this is still on the move, and there are a lot of different factors involved with the removal, replacement, and the possible treatment of ash trees. But the costs involved certainly add up to a lot, in a hurry.”
A recent report issued by Ohio State’s Agricultural Research and Development Center in Wooster cited an estimated cost of $10.7 billion for the treatment, removal, and replacement of only 17 million ash trees on developed land in the states inside the current impact area and some states bordering that area. The report estimated the cost of removing and replacing dead and dying ash trees on public and private land just in Ohio’s communities at $5.2 billion.
As the ash borer spreads, those numbers continue to spike, but the ultimate cost could be incalculable. While blue ash in Michigan has shown some resiliency before succumbing to the borer, the pest has hit white ash, green ash, and black ash trees with a vengeance. Black ash has a significant role in the history and culture of some Native American tribes and is the essential material in their basket-making.
“In Michigan, the green ash is dying out quickly, the white ash has been hit hard, and the black ash, which is so important to many of our Native American groups, has really been hammered by this,” Ms. Usborne said.
In Ontario, where the borer was found in Windsor at about the same time it emerged across the river in Detroit, Taylor Scarr, a forest entomologist with the Ontario Ministry of Natural Resources, is braced for the exposure of a flood of new infestations.
“In some places, I think it is poised to explode, and some of our cities are experiencing that right now,” he said. “Since we’re a little farther north, it takes longer for the life cycle to complete, but in the areas where we’ve seen the borer, such as in Toronto, Sarnia, and Windsor, they’ve all experienced a 99 percent mortality rate.”
Biologists have been at work for nearly a decade on developing a resistant ash tree that can fend off borer attacks and on treatments to protect ash trees from the insect, including soil-applied and trunk-injected systemic insecticides and protective sprays. They are even looking at using female decoy beetles to attract and trap males.
Akhlesh Lakhtakia, a professor of engineering and science mechanics at Penn State, is leading research on the decoy project but admits time is not on the side of the scientists searching for an effective way to stop the borer.
“Within 25 years, practically no ash trees may remain on either side of the St. Lawrence Seaway,” Mr. Lakhtakia said in a recent article posted on the university’s Web site.
Researchers at Michigan State and Ohio State found in a recent report that while certain insecticides effectively can protect ash trees from the insects, trees with significant canopy loss were likely too far gone to make treatments worthwhile. Toledo arborist Rich Savory said his company is treating many ash trees at a cost of about $250 per year for a tree a foot in diameter. Larger trees cost more.
“In the research we’ve seen,” Michigan State’s Ms. Usborne said, “the work on treatments and developing new strains certainly shows promise, but there is a cost factor to consider.”
She offers a somewhat grim outlook as biologists, forest managers, and private property owners grapple with the expected loss of billions of ash trees.
“We know there’s going to be another pest, because we live in a global community,” she said. “We just need to be very smart in how we monitor this type of thing, and how we manage our response.”
Mr. Getz, 76, who saw his ash trees go from healthy to lifeless in just four years, spent more than $4,000 trying to save them but doubts that he was able to even slow down the borer.
“These trees are what sold me on this place when I bought it, way back in 1966. And when I lose even one tree, it hurts. But this has just been awful,” he said. “It’s sickening to think that from that one mistake, we are going to lose millions and millions of trees.”
Contact Matt Markey at: firstname.lastname@example.org or 419-724-6068.