Infestations of the Emerald Ash Borer can take years to detect, which is why the state Department of Conservation of Natural Resources is warning townships about it now, according to DCNR Forest Health Manager Donald Eggen.
"Our recommendation is that if it gets to within twenty miles of you, which it is, you need to get an inventory done and identify which trees you have at risk," said Eggen
"Three to five years after an infestation, 99 percent of all of your ash trees will die of you don't do anything.
This thing has already killed about 50 million ash trees nationwide in 20 states and is continuing to spread," he
The EAB is an oval-shaped green insect less than an inch long that's native to China, but found its way to the United States in the late 1990s and was first found in Michigan in 2002, Eggen
told the board.
Since then, EAB infestations have been found in ash forests across the country and in Canada, and since it was first detected in Pennsylvania in Butler and Allegheny Counties in 2007 has kept coming closer.
"There are about 8 billion ash trees in North America, and we've seen it in the forest along northern Pennsylvania and southern New York - that's where Louisville Slugger
gets their baseball bats, the really nice ash up there," he
An EAB infestation was found in Warrington Township, Bucks County in March and identified by the Penn State Cooperative Extension and state Department
of Agriculture officials in conjunction with DCNR
, and so state officials have been working to get the word out to residents and governments across the state to warn what to look for.
"It's now in 26 counties, and the more we look for it the more we find.
That initial infestation in June of 2007 in Butler Township, had probably been there since 2000 or '99, so when it was discovered in Michigan it was already in Pennsylvania," Eggen
Adult borers lay eggs between the layers of bark on the typical ash tree, and when the larvae hatch they bore into the wood to feed, leaving distinctive S-shaped markings beneath the bark of infested trees.
Fully grown adult borers leave the tree through D-shaped holes in late spring and early summer, but borers often attack trees from the top down, making detection difficult before it's too late.
and other government agencies have developed extensive knowledge of how to treat EAB infestations over the past decade, Eggen
told the board, and find that several main tactics are most often deployed depending on the resources available in certain areas.
Total tree removal often fails because borers can fly from one tree to another, and can be carried through areas in firewood or shipping crates.
Chemical pesticides can be injected directly into trees that can fend off the borers, but the insecticide is a controlled substance that must be applied by trained personnel and can cost as high as $500 per liter.
Biological controls have also been tried in 12 states across the country by releasing three species of wasp that feed on the borers, and those have proven effective where tried so far, but Eggen
told Hatfield's board that the first step for any township is to build its knowledge base.
"If you have ash trees in a park setting or on a street, it's important to know that because when an ash tree dies, it degrades and becomes very brittle in that year," he
"A strong wind or storm will snap it and that tree will come down, so ash trees when they die need to be removed that year," thus the importance of a database and monitoring, Eggen
told the board.