Spongy moth return - Ask Extension
We had an infestation of spongy moths 3 years ago after multiple attempts to physically control we had the area sprayed with BTk the next spring - whi...
Knowledgebase
Spongy moth return #867834
Asked May 10, 2024, 6:44 AM EDT
We had an infestation of spongy moths 3 years ago after multiple attempts to physically control we had the area sprayed with BTk the next spring - which dealt with the worms and gave our forest back. Now 2 years later we have another infestation. I thought that there were supposed to be longer periods as the brood would die off. It appears now we have a lot of the same signs as previously- a large infestation. Are these not dying off ? Should we spray 2 years in a row to wipe out the brood. We had this problem 20 years ago and until recently haven’t experienced the mess that these little buggers produce. Open for your expert opinion. Help us save our forest while being good guardians to our environment
Kalamazoo County Michigan
Expert Response
You are correct that they are typically cyclical in population and it less common to experience an outbreak after a quieter year.
While the caterpillars can feed to the point of defoliating trees, deciduous trees are able to recover and can sometimes even put a second flush of foliage in the same year. Banding trees is one non-chemical option, though not feasible for large lots. Whether you decide to spray depends on the severity of the outbreak and your own tolerance for risk.
If you were to spray the trees, the time to do that is coming up soon. You'll want to check the Enviroweather model for the most accurate times to apply chemicals.
While the caterpillars can feed to the point of defoliating trees, deciduous trees are able to recover and can sometimes even put a second flush of foliage in the same year. Banding trees is one non-chemical option, though not feasible for large lots. Whether you decide to spray depends on the severity of the outbreak and your own tolerance for risk.
If you were to spray the trees, the time to do that is coming up soon. You'll want to check the Enviroweather model for the most accurate times to apply chemicals.
Banding trees sounds good even makes the homeowner feel good but there are millions of them already up the tree eating the leaves. Having lived through this once before and the damage not only to the trees but our property leads me to believe that banding is a pacifier to make the owner feel better. A walk in the woods with frass raining on you doesn’t make the banding seem like it helps. We have a forest here on the 6 acres we live mostly oaks, cherry and maple trees. Some of the neighbors have said that their trees haven’t fully recovered from the last brood’s insult. Thanks for your recommendation- what I really want to know is two applications in concurrent years recommended. Happy to have a visit from your regional agent for suggestions
Sent from my iPhone
Sent from my iPhone
On May 10, 2024, at 10:17 AM, Ask Extension <<personal data hidden>> wrote:
The decision to treat for 1 or 2 years is based on egg mass sample counts in the late fall. If the number of spongy moth egg masses is above a certain number, then it's recommended to treat. See this resource for the explanation: https://extension.psu.edu/guide-to-gypsy-moth-egg-mass-surveying
I understand why you would be frustrated with frass raining down.
I understand why you would be frustrated with frass raining down.
