By Lee Bergquist of the Journal Sentinel

Madison — Seven years after the discovery of the emerald ash borer in
the United States, officials face bleak prospects for trying to
control its spread.

In fact, it might be a lost cause.

Authorities have yet to find a magic bullet to attack the invasive
beetle.

Insecticides have proved to be effective, but applying them over large
areas isn’t practical.

And the most promising tool – unleashing hordes of tiny Asian wasps –
is still in its infancy.

“Unless we develop effective control agents, the cause is lost,” said
Paul Chaloux, program manager of the emerald ash borer program at the
U.S. Animal and Plant Health Inspection Service.

But Chaloux and other government officials and scientists also aren’t
throwing up their hands.

They cite the advances on numerous fronts in a few years’ time,
ranging from a new tool that detects the insect in the wild to growing
public awareness about how humans help spur outbreaks when they move
wood containing ash.

Also, they say the cost of doing nothing could far outweigh the
$154.2 million the Animal and Plant Health Inspection Service
has spent since 2005 on the problem.

“What Paul is expressing seems to be a consistent message I’ve heard
from the research community,” said Darrell Zastrow, director of forest
sciences at the state Department of Natural Resources.

“Personally, I try to be as optimistic as I can.”

The emerald ash borer was discovered near Detroit in 2002, and since
then it has been found in 13 states, including Wisconsin, and Canada.

Wisconsin hasn’t experienced the devastation of states with more
mature outbreaks, such as Michigan, Ohio and Indiana. In those states,
an estimated 53 million ash trees had died or been removed by 2007,
according to experts.

The emerald ash borer was detected in August 2008 in Newburg, on the
border of Ozaukee and Washington counties. New discoveries popped up
this year in locales as far-flung as Franklin, Kenosha, Green Bay and
along the Mississippi River south of La Crosse.

Chaloux and Ohio State entomologist Daniel A. Herms recently explained
the challenges of fighting the emerald ash borer, while detailing the
progress.

The metallic green beetle has proved to be a highly efficient killer,
attacking not only weak trees, as many pests do, but healthy trees as
well, they said.

After the first sign of damage, infested ash trees are dying quickly –
in two to three years, Herms said.

In forests, death starts slowly, “but once mortality gets to 5%, all
of a sudden it takes off like wildfire,” Herms said.

The next year, 30% of ash trees in a stand are dead, he said. The next
year, it’s 70% and the next year it’s 100%.

Across 1,000 square miles of southeastern Michigan, 114 research sites
have showed ash trees with 99.8% mortality, Herms said.

“It attacks all ash trees, and hence the very existence of the genus
is at stake,” he said. “It clears everything in its path.”

In response, ash seeds are being collected and held in cold storage in
the hope that they will one day be replanted to restore native ash
stands. Wisconsin’s DNR plans to start collecting seeds next year.

Over the next decade, infestations will continue to grow. Researchers
from the University of Nevada, Michigan State University and the U.S.
Forest Service predict that the insect will infest trees in most areas
of 25 states from Maine to Missouri – including all of Wisconsin.

And as it spreads, the costs will rise.

Resource economist Kent F. Kovacs of the University of Nevada,
economist Robert G. Haight of the Forest Service and others estimated
in a recent paper that it will cost government and landowners
$10.7 billion to treat with pesticides or remove 17 million
trees in urban areas between 2009 and 2019.

Losses that have decimated hard-hit states such as Michigan and Ohio
aren’t included.

“We need to slow the spread,” Chaloux told members of the Society of
Environmental Journalists on Oct. 9. “That will buy us time to fight
and maybe to solve the problem.”

Possible solution
The brightest hope for now is a trio of parasitic wasps imported from
Asia that feast on the emerald ash borer.

This year, two species totaling 16,000 wasps were released from a new
federal breeding facility in Brighton, Mich., and introduced to
infested areas in Michigan, Ohio and Maryland.

The two species eat the larvae of the beetle. A third species, which
eats eggs from the beetle, is expected to be released next year.

Sites in Wisconsin could be included in next year’s releases,
according to the DNR.

Officials said it will take several years to gauge the effectiveness
of the biological controls.

Meanwhile, Wisconsin is preparing for the devastation.

“I think we will take a lot of damage, but it doesn’t have to be
catastrophic if we can buy some time,” said Andrea Diss-Torrance, a
forest health specialist with the DNR.

“I am really impressed with how fast things have happened.”

Some of those developments include:

Quarantines: Including one in metropolitan Milwaukee that restrict the
movement of ash stock.

Insecticides: One commonly used insecticide contains the active
ingredient Imidacloprid. The City of Milwaukee is using another
chemical, emamectin benzoate, which is injected into the tree and
marketed under the trade name Tree-дge.

The downside is that chemical treatment isn’t practical for entire
stands of trees – but instead is being used for isolated high-value
trees on private and public property.

Diagnostic tools: Notably, the development of a new purple
triangle-shaped trap to attract and detect the presence of the beetle.
Nearly 8,000 traps were hung in ash trees in Wisconsin this year.

Media campaign: This has raised the awareness that humans, ash stock
and firewood play in spreading the hitchhiking insect. The federal
government spent $1.5 million in 2009, including in Wisconsin.

Mick Skwarok, spokesman for the Wisconsin agriculture department,
said, “We need detection and we need treatment, and it’s not come
together yet.”