Spongy Moths

Same Moth, New Name

Lexie Davis, Cornell Cooperative Extension of Yates County Natural Resources Educator & Northwest Regional Director of the Master Forest Owner (MFO) Program

"Spongy moth" has been formally adopted as the new common name for the moth species Lymantria dispar (or “gypsy moths”) by the Entomological Society of America (ESA). This was announced by the Better Common Names Project (BCNP) on March 2^nd, 2022. This project is a task force within the ESA to address problematic common names that contain derogatory terms, inappropriate geographic references, or inappropriately disregarding what the insect might be called by native communities. These problematic names perpetuate harm against people of various ethnicities and races, create an entomological and cultural environment that is unwelcoming and non-inclusive, disrupt communication and outreach, and counteract the very purpose of common names.

Starting the process in July 2021, the previous name, “gypsy moth” was removed due to its use as a derogatory term for Romani people. After evaluating more than 200 names, the “Spongy Moth” was selected (and is the first change undertaken by the Better Common Names Project).

The name — derived from the common name used in France and French-speaking Canada, "spongieuse"— refers to the moth's sponge-like egg masses (an important target for management efforts of this invasive forest pest).

To stay informed whenever there is an update, including any future name changes or proposed changes from the BNCP, visit their website at https://www.entsoc.org/publications/common-names/better-common-names-project.

Within the last two years, the Finger Lakes region of New York has seen a significant increase in the number of spongy moth infestations. It is important to note that this forest pest can defoliate hundreds of tree and shrub species, so it is important to keep an eye out and prevent its spread when possible! A single spongy moth can eat as much as eleven square feet of leaf area per day!

Fortunately, there are a couple of ways you can help in reducing the spread of Spongy Moth. You will soon see the eggs start to hatch as they emerge in April or May in clusters of 100-600+. To help prevent the spread of the spongy moth, you can scrape off any egg masses that you find and put them in hot soapy water. The hot soapy water ensures that they will not be able to hatch! You can also wrap the tree trunk in burlap in the early spring. The burlap traps the caterpillars as they move up and down the trunk for feeding and molting.

During outbreaks, manual removal may become tedious and does little to reduce the overall population of spongy moths, so spraying may be a practical and effective option. There are various insecticides are available for spongy moths, including microbial/biological and chemical sprays. The most used microbial/biological insecticide used for spongy moths is Bacillus thuringiensis (kurstaki), commonly known as Bt or Btk, which is naturally occurring on plants and in soil. It is harmless to people, animals, and plants but does affect other young moths and butterfly larvae.

Several chemical insecticides are labeled for use on spongy moths, but keep in mind that these can have an impact on a wide variety of beneficial, native insects, birds, and other animals, so they should be used wisely. Spraying of Btk or chemicals is not at all effective during the pupae or egg mass stages.

For questions or additional information, contact CCE Yates Natural Resources Educator, Lexie Davis at abd97@cornell.edu or (315) 536-5123.

Last updated July 24, 2023