Storms are carrying grass-destroying pests to northeastern U.S.

Homeowners beware: Armyworms are on the march in numbers not seen in decades, threatening yards, golf courses, athletic fields and crops in the northeastern U.S. Defenses against the invasion are weak.

"The general consensus is that this is the worst outbreak of fall armyworms in decades," David Shetlar, professor emeritus of entomology at the University of Ohio in Columbus, said in an email. "From Iowa to New England and south, this is the worst." Hot weather and drought conditions have helped produce higher-than-usual numbers of the subtropical moths in the southern U.S. The dry climate, coupled with recent storms, have the insects heading north, where they are feasting on lawns as far up as New York, Thomas Kuhar, a professor of entomology at Virginia Tech in Blacksburg, told CBS MoneyWatch.