GRAND RAPIDS, Mich. (WOOD) — The city of Grand Rapids is asking for the public’s help to fight spongy moth caterpillars.

Spongy moths, formerly called gypsy moths, are invasive in Michigan. They can defoliate trees, which makes the trees more susceptible to diseases that could kill them.

“It’s an insect that’s been in Michigan for 50 years and populations rise and fall,” Grand Rapids Parks and Recreation Superintendent Joe Sulak said explained.

Through late April, people can look for the light brown, spongy-looking egg masses on tree trunks. Gently scrape them off using a plastic putty knife or other dull tool into a bucket of soapy water to destroy them.

“What you want to do is look for egg masses on the underside of larger limbs of oak trees, maple trees, I’ve even seen them growing on linden trees,” Sulak said. “When the populations are really high, they’ll even attack conifers as well.”

Leave the eggs in the soapy water for 48 hours, after which you can throw them in the trash.

“(The eggs) have been there all winter and they won’t really start hatching until late May, so we’ve got some time,” Sulak said.

A spongy moth caterpillar. (AP File)
A spongy moth caterpillar. (AP File)

Once the eggs start hatching, you can wrap the trees with duct tape, sticky side out, to trap the caterpillars, he said.

The city has crews that work to get rid of spongy moths every spring, but there are so many that it needs the public’s help.

“We just wanted to get the word out that we can do a lot individually to help control the populations in our yards and along streets,” Sulak said.

You can find more information about the city’s efforts to combat spongy moths on its website.