Skip to main content

It’s in your nature: Gypsy moth

  • Empty

    Dozens of female gypsy moths are placing their egg masses on this pin oak. These 40-plus egg masses could hatch 20 to 30 thousand caterpillars. This was only one section of the trunk photographed. BARRY REED/SPECIAL TO THE TIMES NEWS

  • Empty

    A male moth, darker and smaller than the female, fertilizes the eggs. The males are the best fliers, and since the female is so laden with eggs, males use her scent to guide them to mate.

  • Empty

    The gypsy moth caterpillar is very “hairy” and grows so rapidly that few birds prey on them. Note the size comparison.

Published June 08. 2019 05:51AM


One of the most destructive insects in North America is the gypsy moth. Native to Europe and Asia, it was released by accident (brought here as a possible alternative to the silk worm) near Boston. That was in 1869.

About 20 years after it began spreading, the first federal and state attempts were made to eradicate them. The spraying efforts proved ineffective. They now have spread to more than half of the U.S., radiating from that release area.

Gypsy moth host plants number in the hundreds, however oak and aspen trees are its favorites. I did a college photography assignment in 1973 and photographed tremendous defoliation in Franklin Township. Thousands of acres there were completed defoliated. I believe this also affected much of Carbon County. That year they even ate a last-ditch food source for them, white pine needles.

A summer walk in the forest was surreal. The forest floor was covered in ferns, but the forest canopy was bare as if it was December. No vireos, flycatchers or tanagers were singing.

There were nest failures, and in many cases no attempt was made in the defoliated regions because there was no food or cover available. The forest areas had been severely defoliated the prior year and the 1973 defoliation “wiped out” most of the white oaks and many chestnut and red oaks as well.

Since then, various areas of the Times News region have experienced gypsy moth eruptions a number of times. Just 3 years ago I was quite familiar with the outbreak in the East Penn and West Bowman corridor.

Many of the oak trees didn’t survive, and numerous homeowners have been removing the oak tree “skeletons.” Since fewer white oaks remained, the chestnut oaks took a “beating.” If you drive south on Mahoning Mountain Drive or travel Maury Road, look for the dead oaks. In a future article I will focus on this and many other forest threats.

Even though efforts were made to stop the spread of this insect, the task was difficult. The newly hatched tiny caterpillars produce a thin web (gossamer) which catches the wind and may carry them from ridge top to ridge top. Hanging laundry catches them hundreds of yards from the nearest trees. Fortunately, some natural controls are helping, including a virus, fungus and about 20 parasitic wasps and flies.

Birds do little to control the caterpillars. The hairy bodies make them harder to eat (less palatable) and the rather uncommon two cuckoo species are not numerous enough to control the leaf-eating scoundrels.

After mating, the female lays her egg mass of more than 500 eggs on tree trunks, windowsills or your camper. They overwinter in this egg stage. They should be hatching by this publication, but from the few egg masses I’ve found, this may not be a devastating season.

Test Your Outdoor Knowledge: Which of these state mammals has the most teeth? A. porcupine, B. white-tailed deer, C. black bear, D. opossum.

Last week’s trivia answer: Found almost everywhere in the state, the redback salamander is the most common species.

Contact Barry Reed at



Classified Ads

Event Calendar


December 2019


Upcoming Events

Twitter Feed