Slowing the Spread of Gypsy Moths

Karen Schaefer- It's early spring in Northeast Ohio and the trees haven't leafed out yet in the Cleveland Metroparks' Brecksville Reservation and nearby Cuyahoga Valley National Recreation Area. But there may not be many leaves this year. Some people are worried that many of these trees are already dead.

John Clelland- And you can see where you start out with very green trees and end up with something like this. I mean, there's just no leaves left on the tree whatsoever. Totally devastated. All you see is just branches.

KS- The culprit is the gypsy moth, an exotic insect species introduced to North America over a hundred years ago and - until recently - confined largely to the New England states. But a few years ago, the moths started showing up in Ohio. The problem is the gypsy moth caterpillars, which defoliate millions of acres of trees in the U.S. each year. John Clelland is a resident of Greenwood Village, a condominium community in Sagamore Hills Township.

JC- See, every one of these egg masses has 500-1,500...and look at them here. There's probably 300 or 400 on this one tree. Multiply that by 5-1,500 eggs and they'll just be all over the place...So you just have to spray.

KS- Last year was the first for gypsy moths in Sagamore Hills, but neighboring communities like nearby Brecksville on the other side of the Cuyahoga River have seen several years of devastation wrought by the wriggling caterpillars. This year the residents of Greenwood Village will join their neighbors in a voluntary gypsy moth suppression program offered by the U.S. Forest Service. Sagamore Hills Township Trustee Rose Mary Snell says it's important to work together.

Snell- We have a very jagged edge along our western border where the park abuts us and it's real important that the park do some spraying, too, because if we do it only in our area, those gypsy moths are going to come back over and defoliate more of our trees.

KS- The Cuyahoga Valley National Recreation Area is currently considering a suppression program within some areas of the park. But while spraying insecticides may help to lower infestations, Brad Onken, an entomologist with the U.S. Forest Service in Morgantown, West Virginia, says the gypsy moths are here to stay.

Brad Onken- You can't possibly try to eradicate a pest like the gypsy moth because of its nature and its far spread over a large geographical area and we certainly wouldn't propose that we spray insecticide on a broad scale like that...So the whole point is we focus in on selected resources that the land managers consider important enough that they can't tolerate any damage.

KS- The suppression program uses two insecticides, one a naturally-occurring virus that affects only gypsy moth caterpillars and is expensive to manufacture. The other is baccillus thuringiensis or Btk, a common insecticide for home gardeners concerned about long-term environmental effects. Onken says Btk has only a one to two week effectiveness, but it can kill other species of moth and butterfly caterpillars.

BO- ...if you're interested in lepidpotary or moths and butterflies, the downside is it does have the potential to affect other species.

KS- Onken says the reason gypsy moths are so tough to kill is that they don't really belong here.

BO- Gypsy moth, being an exotic, has such a potential to build up in mass numbers. It doesn't have the parasites and predators and natural control organisms that these native species do.

KS- Gyspy moths aren't the only exotic species threatening U.S. forests. Over the last 50 years, both the American chestnut and the elm have been wiped out by exotic species diseases introduced from other countries. Donna Leopard, a U.S. Forest Service entomologist stationed in Asheville, North Carolina, says the number of exotic species found in the U.S. each year is growing.

Donna Leopard- I don't know if it's because we're getting better at monitoring for exotics, but, yes, there does seem to be an increase in the number of exotics that are coming into the country. And I suspect that it's directly linked to international trade.

KS- Scientists are closely monitoring a number of new exotics, among them the hemlock wooly agelid, the Asian long-horn beetle and various other wood borers and bark beetles. Leonard, who oversees the Forest Service's program to slow the spread of the gypsy moth, says one solution is to quarantine affected areas.

DL- In forestry, when people move logs around when they're timbering, since gypsy moth egg masses are usually found on the boles of trees, you're not supposed to ship whole logs from an area that is generally infested to an area that is not without first de-barking them.

KS- But despite these efforts, most of the exotic species threatening U.S. trees are continuing to spread. Outside of primary infestation areas, low density gypsy moth populations are being destroyed whenever possible through the Slow the Spread program. But researchers believe it's only a matter of time before other parts of the country will be begin to rely on the regular use of suppression programs to keep infestations like the gypsy in check. For INFOHIO/90.3, I'm Karen Schaefer in Cuyahoga County.

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