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Gypsy Moths

During a bicycle trip on Martha's Vineyard several years ago, my companion and I stopped in the state forest to rest for a few minutes. While we chatted, we gradually became aware of the sound of gentle raindrops overhead and felt things dropping on our helmets. Looking up, we realized that the rain sounds were actually gypsy moths munching on tree leaves and the raindrops on our helmets were really gypsy moth caterpillars falling on our heads. We got out of there fast!

The gypsy moth was introduced to North America in 1869 so that it could be interbred with silk worms to create an industry. That plan went awry when they escaped from a private residence in Massachusetts and quickly became a nuisance. Their favorite trees include oaks, aspen, birch, willow, and poplar. They will also go for fir trees if they get hungry enough. One or two years of moth-related damage will probably not kill a tree, but several years of attacks can significantly weaken it and may cause its demise.

Last year saw a dramatic increase in the gypsy moth population. Experts are predicting that this year's invasion of gypsy moths in the Northeast could be the worst infestation since 1981, when 12.9 million acres were defoliated and homeowners resorted to hosing down their driveways and houses in an attempt to combat the hordes of creeping invaders. Several consecutive years of dry conditions is reportedly to blame for the moth's increasing numbers. What's a homeowner to do?

Nature may help us out this year. It's been a very rainy spring so far, which may be good news. Moisture helps to spread a naturally-occurring fungus that kills the caterpillars and reduces the population. The moths can also be affected by viruses that exist naturally.

Barrier bands of sticky tape or adhesive gels can be placed on tree trunks to prevent the larvae from crawling up the tree. Forcefully spraying the trees with water can knock many off and can be repeated as needed. Destroying egg masses found around the house can help reduce the population (but be careful not to touch the can get a nasty rash if you're allergic to the hairs). A scan of the internet reveals a variety of homemade barriers and traps that the homeowner can also try. Chemical and/or biological pesticides can be sprayed to kill the pests, but these are best applied by a licensed professional.

Gypsy moth populations wane and ebb over the years. Even if this turns out to be a bad season, the population will likely diminish significantly in the next year or two. In the meantime, the most we can do is put up the best fight our time and wallets allow and hope that Mother Nature is on our side.