2023 Spongy Moth Spray
Notice of Spring Treatment and Public Hearings
In response to resident requests, the City of Wyoming has a long-standing practice of providing spongy moth monitoring and a spring treatment as needed. Information and updates will be available here throughout the process.
March 7, 2023 UPDATE: The first mailing has now been sent to property owners impacted by the 2023 spongy moth spray program. This first letter contains information about public hearings associated with the program.
The first public hearing of the proposed 2023 spongy moth spray will be held on March 20, 2023, as part of the regular City Council meeting. During this meeting, the City Council will take public comment from interested persons affected by the proposed project. The notices linked below have been mailed to all property owners in the treatment area, describing the process and how to provide public comment.
March 21, 2023 UPDATE: The second mailing has now been sent to property owners impacted by the 2023 spongy moth spray program. This second letter contains information about public hearings associated with the program.
The second public hearing of the proposed 2023 spongy moth spray will be held on April 3, 2023, as part of the regular City Council meeting. During this meeting, the City Council will take public comment from interested persons affected by the proposed project. The notices linked below have been mailed to all property owners in the treatment area, describing the process and how to provide public comment.
2023 Treatment Locations
Using resident complaints, tree damage assessments and egg mass surveys, our consultant, Aquatic Consulting Services, LLC, determined the areas of treatment. A total of 698 acres are scheduled for treatment this year. You can find treatment locations on the Aerial Spray Map 2023 (PDF) or use the Interactive, Searchable Spongy Moth Map.
Property Owner Cost
If a property you own is within a treatment location, a fee is assessed on your 2023 Summer property tax bill. The fees will be as follows:
- $28 for small parcels or treatment areas equal to or less than .5 acres
- $83 per treated acre for parcels with treatment areas larger than .5 acres
How It Works
In addition to working with Aquatic Consulting Services, we partner with Hamilton Helicopters, Inc. to perform spongy moth treatment in late-May to early-June. The exact date is determined through continued monitoring of weather conditions, as well as caterpillar and tree canopy development. Spraying will be done when average wind speed is less than 10 miles per hour and relative humidity is more than 50-percent. In most cases, this limits spraying to a morning activity.
The insecticide used in this process is a naturally occurring bacteria called Bacillus thuringiensis (Bt), which is also used by organic gardeners, and the Bt brand used is Foray 76B (or equivalent). On treatment days, our contractor will apply 1 quart of the Bt material over each acre in a very fine mist. It is unlikely for people to see or feel it. Application generally takes 4 - 6 hours (for the entire city) and the product dries within minutes.
The Bt only affects the caterpillars of moths and butterflies that are actively feeding at the time of treatment, which is why the application date varies. In an effective spray application, you may notice a change in the level of activity and responsiveness of the caterpillars, and they will die in 5-7 days.