City provides tips to help control spongy moth population

City provides tips to help control spongy moth population

Published on March 20, 2023

GRAND RAPIDS, Mich. - The City of Grand Rapids Forestry division is asking for help from residents in controlling the population of spongy moth to protect the City's urban tree canopy.

Spongy moth is an invasive species that has been present in Michigan for over 40 years. Spongy moth egg masses can contain over 1000 larvae that hatch into leaf-eating caterpillars. When the caterpillars significantly defoliate trees, the trees become weaker and vulnerable to fatal diseases.

The City's Forestry division does its best to target and treat the most densely populated areas of spongy moth but relies on community members to help with the rest. The needed tools are common household items, so most residents can get started right away.

Here are the ways community members can help control spongy moth populations in Grand Rapids:

• Now through late April: Look for egg masses on tree trunks and scrape them into a cup of soapy water using a plastic putty knife or other dull scraping tool. Egg masses are light brown, sponge-like in appearance and about the size of a quarter.

• Late April through late May: Wrap a double band of duct tape around tree trunks with the sticky side facing out to prevent hatched caterpillars from moving up the tree to the leaves.

For more information on spongy moth, how to identify egg masses, and video tutorials on egg mass scraping and tree wrapping, visit the City's website HERE.

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