Your best defense against any one pest or disease is a diverse and healthy forest to begin with. We recommend reaching out to a certified forest manager for site-specific evaluations and recommendations.
August through to May - Egg Mass Scraping
Removing egg masses from trees and any other immovable object that you might find them on. It’s the easiest way to target the most numbers as one egg mass can contain up to 1,000 potential caterpillars. Egg masses should be scraped into a container of soap and water (no need for anything else), as seen in this
video, and left to sit in the water for at least 48 hours before being discarded. Be sure to wear gloves as any contact with even the eggs can result in allergic reactions.
May to July - Burlap Banding
Note this method requires daily monitoring and cleaning.
Once the caterpillar has hatched from the nest, it starts climbing up and eating leaves. The Spongy Moth prefers oak trees but will eat the leaves from most any deciduous (leaf bearing) tree. Burlap banding is the best way to capture the most caterpillars as they move up and down trees to get out of the hot sun.
Burlap banding requires placing a large piece of burlap around the entire circumference of the tree, at about waist height, then tying it off with some string or rope in the middle, and then folding the top of the band over the bottom as seen in this
video demonstration. This creates a shelter that will capture the caterpillars as they go down the tree during the day to escape the heat and predators and then again climb up to feed. You need to check and empty these burlap bands daily, scraping them into a bucket of warm soapy water for a few days, covered with a lid so they can’t get out. Simply scraping them to the ground will not kill them.
Time dependent on egg hatching
Spraying an organic pesticide called BTK is possible but requires careful understanding of caterpillar life stages and timing. As it is a non-specific pesticide, meaning it will kill all caterpillars that ingest the leaves it’s sprayed on, even helpful species, we urge extreme caution and avoidance if possible. This option should only be used by skilled professionals who understand life cycles and the small window of opportunity to have an impact with minimal effect on other species.
Using any sort of sticky tape tied around trees. This can inadvertently capture other species including birds, small mammals and snakes.
Not to scare you but there are many worse invasive species...
There are other diseases and pests that are more difficult to manage and have already seriously impacted our forests – like Emerald Ash Borer, Hemlock Wooly Adelgid and Brown Spruce Longhorn Beetle to name a few.
There are a number of new invasives species like the
Spotted Lantern Fly and new diseases such as
Oak Wilt to be concerned about.
What are we doing?
As a conservation agency, we have a role to play in understanding the science. Together with other conservation authorities, government agencies and municipalities, we collaborate to learn as much as we can and have participated in direct monitoring.
We have a teaching role about the underlying ecology, forest health and management options. Understanding the species and impacts is key in making the best decisions. We promote accurate, science-based information through the media and social media, and support our municipal and provincial partners.
As one of the largest landowners in Ontario, conservation authorities need to manage our own trees and forests. That means, like many residents, we evaluate and take action when needed to reduce overly negative impacts. While it’s comforting to know we aren’t overly concerned about the impact of Spongy Moth, at the same time there are many other risks to our trees and woodlots that do garner our attention.
We Help Grow Forests!
We offer funding and expertise to landowners who want to grow or expand existing forests in the Lake Simcoe watershed. New woodlots, windbreaks, streamside plantings are all projects we not only encourage, but support with grant funding. We’ll cover as high as 90% of project costs in some cases. Check out our
restoration funding program for more details.
Spongy Moth is Food for Birds
Remember, the Spongy Moth caterpillar is food for birds at a time when mother birds are looking for good sources of protein to feed their babies.
* The Spongy Moth was originally called the European Gypsy Moth but the name was recently removed from the list of commonly accepted names because of it is a derogatory slur often used to describe the Romani people. Its scientific name is Lymantria dispar dispar.
Lymantria dispar dispar (LDD) and European Gypsy Moth refer to the same insect. While all our public communications use Spongy Moth, at times we link to some materials not created by us where you may see
Lymantria dispar dispar (LDD) or European Gypsy Moth used.