Urban Forestry crews will be spraying spongy moth egg masses in District 11 starting at the intersection of S. Whitney Way and Mineral Point Rd.
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Starting this week, crews from the Urban Forestry section will be out treating egg masses on trees in the City right of way / terrace areas starting at the intersection of S. Whitney Way and Mineral Point Rd.
Forestry crews will be working on this egg mass treatment as conditions allow. It will start this week and it will probably last into early 2024 since the crews need weather to cooperate for this work to proceed.
Where is this work happening?
Urban Forestry crews will be focusing on trees within the terrace / right of way spaces in the area within area of the Google map snipped out below:
What are the Urban Forestry crews doing?
Crews will be spraying spongy moth egg masses with a soybean-based oil. It’s called horticultural oil.
The crews will be using backpack sprayer and hand pump sprayers that will be familiar looking to most homeowners as these like the hardware store variety of spraying devices.
Why are they doing this?
The oil smothers the egg masses and deprives them of oxygen so they cannot hatch in the spring.
Destroying egg masses is a great way to address the spongy moth problem as these egg masses can hold 1,000 eggs for the caterpillars that cause the defoliation you see in the spring.
Why do it now? And why does the weather matter?
Spraying the masses with oil is best done after the first hard freeze, which we have had. There is tiny parasitic wasp that also attacks the egg masses, and it is best to wait until these natural predators have had a chance to work. Once the freeze occurs, and the wasps burrow in for the winter, then the spraying can commence.
You do need to wait until temperatures are above 40 degrees to spray, however, so the horticultural oil does not freeze. With fall planting completed, and temperatures favorable, forestry crews are able to perform this work starting December 7th.
What can homeowners do for trees on their property?
What can homeowners do for trees on their property?
The City has a spongy moth dedicated website that links to several resources for homeowners, www.cityofmadison.com/SpongyMoth.
On the city page there is also a simple guide on what you can do to find, scrape, soak, and trash the egg masses. There’s also this 20 second long DNR video that can show you how to do it, too.
Who do I contact with additional questions?
Bryan Johnson
City of Madison Streets Division
Recycling Coordinator/Public Information Officer
Alder William Tishler
District 11
Contact Alder Tishler