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Full of Frass: Concerned Nutmeggers Gather at CFPA to Learn About Gypsy Moths

Yesterday, on a humid July evening, Nutmeggers hoping for some good news regarding this years’ Gypsy Moth infestation made their way to CFPA headquarters to hear Master Naturalist Brad Robinson discuss the biology, history and control of Gypsy Moths in Connecticut.


Robinson began the presentation with an overview of the notorious moths’ journey to Connecticut. The Gypsy Moth (Lymantria dispar) was first brought to the U.S. (specifically, to Medford, MA) from France in 1869 by Etienne Leopold Trouvelot, who was interested in seeing if he could cultivate them for silk production. It wasn’t long before they escaped and started wreaking havoc on the trees of Massachusetts. They were first discovered in Stonington CT in July of 1905, and were present in all 169 Connecticut town by 1952.


If you live in Connecticut, you’ve likely encountered a Gypsy Moth. In fact, it’s very possible that you’ve suffered the impacts of an infestation on your property or a nearby park: defoliated or dead trees, caterpillars clinging to your clothes, and frass (caterpillar waste) falling from the trees into your hair, your coffee, or your picnic. You can go ahead and blame Etienne and his silk dreams for this. 


So how did we fare this season? According to Brad, we still need some time to assess this years’ damage, but the spread of a virus (Nuclear Polyhedrosis Virus, or NPV) and a fungus (Entomophaga maimaiga) that kills Gypsy Moths certainly did a number on the population. As rain helps to spread the fungus, the wet spring we had was a key factor in slowing the population growth this season. Anecdotally, attendees of Brad’s lecture reported seeing trees in their various towns covered with hundreds of dead Gypsy Moth caterpillars. 


So when will have more definitive information on this years’ infestation? We’ll have to wait for the results of Connecticut’s Forest Aerial Survey, conducted each year from late June to early August. Though the survey originally focused on Gypsy Moth defoliation, it has expanded to include other types of forest damage, such as Emerald Ash borer and Hemlock Woolly Adelgid.


During the presentation, Brad answered a number of questions regarding the control of Gypsy Moths, including some regarding the manual removal of egg masses from trees. Many participants were surprised to learn that scraping the egg masses off the trees isn’t enough - - they will still hatch! Putting egg masses in soapy water, or in a mix of oil and water works best for successfully killing the egg masses. For more information on control and natural predators of Gypsy Moths, visit the Connecticut Agricultural Experiment Station Website: http://www.ct.gov/caes/cwp/view.asp?a=2826&Q=588414&PM=1