The Creepy Crawly Tree-Killer

Just the sight of them can make your skin crawl; at its worst ... "if you can make you imagine a scene from Fear Factor," Arlene Greenway said.

The creepy crawlers are Gypsy Moth caterpillars, and they're chomping through tree foliage in forests, backyards and even on college campuses.

"I jumped off my bike and I was covered with them," Deborah Bourne told CBS News correspondent Michelle Miller.

Forest ecology professor Sarah Webb says the caterpillars have decimated hundreds of Drew University's century old white oaks.

"Well, if you look up to the canopy here, the upper parts of the forest, you'll see it looks like an early spring or even winter in many places," Webb said.

Scientists are concerned because this is when trees are at their fullest and greenest. Those infested may not die immediately, but will be stressed into next season. Another round of these critters could wipe them out.

Brought here from Europe in the 1860's, they've eaten at a rate of five miles a year from New England to Virginia, west to the Great Lakes.

But this year they've feasted on the Mid-Atlantic, chewing through 200,000 acres in New Jersey, 50,000 acres in Maryland. Last year they tore through 700,000 acres in Pennsylvania.

A naturally occurring fungus usually keeps them in check, but that's not so this spring because of unusually dry weather. Now eradicating them entirely is nearly impossible.

"We can't come outside," Greenway said.

Humans suffer through a few more weeks. That's when the bulk of the bugs become gypsy moths and fly away.