Cape & Islands News

Goodbye leaves, here come the Gypsy Moths

A severe caterpillar outbreak expected, putting foliage at risk
"It looked like spray-on insulation," she said. ''It's just unbelievable"

By Matt Carroll, Globe Staff | March 12, 2006

Area communities can expect to be hit next month with another massive outbreak of leaf-eating caterpillars, which have defoliated thousands of acres of trees in Southeastern Massachusetts over the past few years, said officials who track such infestations.

Deborah C. Swanson, a horticulturist with the Plymouth County Cooperative Extension office in Hanson, which educates people about agriculture and horticulture, said she expects an especially heavy outbreak of gypsy moth caterpillars because of the number of eggs that have been laid.

It could be the worst hatching since the period between 1979 and 1981, when millions of the voracious, 2-inch, hairy caterpillars munched their way across the state from the Connecticut River to the ocean.

Swanson said two other pest caterpillars that have left their mark over the last few years -- the winter moth and forest tent caterpillar -- also could have strong years, based on the numbers of eggs laid. Because all three species are expected to reproduce in large numbers this year, the caterpillar invasion could be the biggest in recent memory, she said.

The gypsy moths lay tan or buff-colored oval egg masses, which are about the size of a quarter or half-dollar, and are covered with fine hairs. Each mass contains about 500 eggs.

In Hanson, Swanson said she recently saw a 20-foot branch of an oak tree covered with the egg masses. ''It looked like spray-on insulation," she said. ''It's just unbelievable"...

With no known predators, its population has exploded south of Boston and across Cape Cod. Eggs hatch in late March or early April as buds are swelling but not yet open, and the caterpillars eat foliage and some flower buds of oaks, ash, and blueberry and crabapples, according to information from the UMass Extension service... Read the rest of today's Globe story here, and comment below.