Spongy Moth (formerly Gypsy Moth) in Michigan
MODERATEInsect
Spongy Moth (formerly Gypsy Moth) is currently active in Michigan. Watch your susceptible trees closely and act early.
About Spongy Moth (formerly Gypsy Moth)
An invasive moth introduced to Massachusetts in 1869. Caterpillars defoliate hundreds of tree species, preferring oaks. Repeated defoliation weakens and can kill trees, especially when combined with drought stress.
Symptoms to watch for
Large-scale defoliation of hardwood canopy, tan egg masses on tree trunks and outdoor surfaces, hairy caterpillars with blue and red dots feeding on leaves, extensive frass on ground beneath trees
Trees at risk in Michigan
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Treatment options
Btk (Bacillus thuringiensis var. kurstaki) Spray
Aerial or ground application of this naturally occurring bacterium that kills caterpillars when they ingest treated foliage. Highly targeted with minimal impact on non-lepidopteran species.
Egg Mass Removal
Scraping egg masses from tree trunks and surfaces into soapy water during fall and winter. Practical for individual property owners with moderate infestations.
Mating Disruption (Disparlure)
Aerial application of the synthetic female pheromone disparlure in the Slow-the-Spread program to confuse males and reduce reproduction in low-density populations along the expanding front.
Recommended Products & Tools
Helpful supplies for managing Spongy Moth (formerly Gypsy Moth). Always read and follow label directions, and confirm a diagnosis before treating.
Organic control that targets caterpillars when they're young.
Knocks down soft-bodied pests like aphids, mites, and scale crawlers.
Smothers overwintering eggs and crawlers; dormant or summer rates.
Soil-applied protection taken up by the tree for season-long control.
Sharp, clean cuts to remove affected wood — a tree-care essential.
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Need help with Spongy Moth (formerly Gypsy Moth) in Michigan?
Connect with ISA Certified Arborists serving Michigan:
Browse all Michigan arborists →Frequently asked questions
Is Spongy Moth (formerly Gypsy Moth) in Michigan?
Spongy Moth (formerly Gypsy Moth) is currently active in Michigan. Watch your susceptible trees closely and act early.
What does Spongy Moth (formerly Gypsy Moth) look like?
Large-scale defoliation of hardwood canopy, tan egg masses on tree trunks and outdoor surfaces, hairy caterpillars with blue and red dots feeding on leaves, extensive frass on ground beneath trees
What trees does Spongy Moth (formerly Gypsy Moth) affect in Michigan?
It affects Apple, White Oak, Red Oak, Paper Birch, American Linden, Weeping Willow. Susceptibility varies by species.
How do I treat Spongy Moth (formerly Gypsy Moth)?
Options include: Btk (Bacillus thuringiensis var. kurstaki) Spray, Egg Mass Removal, Mating Disruption (Disparlure). Confirm the diagnosis before treating, and consider a certified arborist for high-value trees.