Gypsy Moths

An invasive species from Europe and Asia, the gypsy moth was introduced by a scientist living in Massachusetts in 1869, who was interested in breeding silkworms.  Not long after, some of the insects escaped and began to establish themselves (USDAFS 1989).  Millions of pure forests stands have been decimated by this little caterpillar.  Of course, as many homeowners may already know, they do not limit themselves to natural forest stands.  They are happy to enter our yards as well.

In the early spring, gypsy moth caterpillars hatch from their tan, oval-shaped egg sack.  Hundreds or up to a thousand tiny caterpillars crawl from each egg sack and make their way to greenery, often using silken threads so they may be dispersed by the wind.  As the caterpillars grow in size in the next several weeks, the amount of food they need to sustain themselves increases exponentially.  Seemingly overnight, whole areas of the canopy of a mature tree are defoliated.  That is when Integrity Tree Services receives phone calls.

Unfortunately many times with gypsy moth caterpillars, homeowners notice them only after the bulk of the damage is done. Colossal trees and forests can be put to waste in infested areas after thousands and thousands of caterpillars have their fill.  Beginning at just centimeters long, these caterpillars quickly grow to about 2 inches in a matter of weeks.  Once the caterpillars are identified, treating for them is not the tricky part, it is noticing the infestation before the majority of feeding damage occurs.
A female gypsy moth lays an egg sack in late summertime and dies soon after.  The egg sack remains over the winter and once the climate is right in the spring, the eggs hatch and the caterpillars emerge.  The caterpillars reach maturity after roughly 7 weeks in mid-summer, from there they pupate.  The pupation stage lasts for 1-2 weeks, and then a moth will emerge.  Once a moth, the brown male moths will fly around in search of flightless, white females (Johnson & Lyon, 1991).  It can be apparent where there has been an infestation of gypsy moth caterpillars during mid to late summer, for one will see dozens of brown gypsy moth males, fluttering all around.

Be sure to monitor your landscape in May of 2017, when the gypsy moth caterpillars grow large enough to be noticed.  Also keep an eye out for the egg sacks, which are usually laid in August.  If found and if within reach, destroying them with a stick is affective on a small scale. The gypsy moth caterpillars are easier to identify when they are larger, right before they pupate.  Look out for fuzzy caterpillars with blue and red spots. There are other caterpillars, which congregate in numbers, which could be mistaken for gypsy moth caterpillars, such as eastern tent caterpillars and fall webworms.

If you think you may have a gypsy moth caterpillar infestation starting, feel free to take a picture and email it to in order to receive confirmation of the infestation.  If you are unable to send a photo, feel free to call (616) 301-1300 extension 118 to schedule a free estimate with one of our certified arborists.

Most of the time, we can get our technicians to the scene same-day. Fortunately, there are some natural defenses present in the environment, which help control caterpillar populations. There is a soil-born fungus, which kills a large number of caterpillars, there is also a virus, and there are predators including, birds, parasitic wasps, flies and beetles (Johnson & Lyon 1991).

Be on the lookout for gypsy moth caterpillars next spring!  If you see them, call Integrity Tree Services right away!