Unfortunately, the spongy moth caterpillar invasion in New York State is affecting more than just our local trees.

It's been a rough spring for many New York residents suffering from invasive spongy moth caterpillars. Not only do they pose a threat to local trees (oak leaves are one of their favorite snacks), but when the leaves are digested, a whole other problem presents itself: permanent poop stains.

Photo of spongy moth caterpillar poop
All those droppings on your property are most likely from spongy moth caterpillars (Canva/TSM Poughkeepsie)

Spongy Moth Caterpillars in New York State

It's bad enough that thousands of tree-dwelling spongy moth caterpillars are making it rain poop in New York, but many homeowners are also discovering that the droppings are staining sidewalks, patios, and nearly every other surface they touch.

Photo of spongy moth caterpillar poop
Many New York residents are finding out the hard way that spongy moth caterpillar poop is hard to clean (TSM Poughkeepsie)

Removing Caterpillar Poop Stains in New York

"Does anyone have any experience in removing the caterpillar poop from patio pavers?", came the question on a local community Facebook page. "We have tried our pressure washer, which is 2300 PSI, but it does not shift it". Luckily, some other residents were already coming up with new solutions.

Photo of algae cleaner and spongy moth caterpillar poop
One New Yorkers recommended this algae cleaner to remove spongy moth caterpillar poop from patios (TSM Poughkeepsie/Lowes)

What Cleaners Work to Remove Caterpillar Poop Stains?

"I had trouble on my deck too but what I found worked was the mold-mildew-dirt-grime cleaner in a gallon with spray nozzle", replied one commenter. "I bought a very strong bristle brush with the long handle... Connected the chemical to my hose did a pre wash and initial scrub and a second time did the trick... Spent about 40 bucks but at least I can walk outside and eat without being grossed out". Check out one option here.

photo of muriatic and spongy moth caterpillar poop
A landscaping professional recommended the use of muriatic acid to remove spongy moth caterpillar poop (TSM Poughkeepsie/Home Depot)

Using Muriatic Acid to Remove Caterpillar Poop Stains in New York

"The only thing that will work is an acid wash", offered someone identifying themselves as a landscaper. "You can buy muriatic acid and follow directions... It does strip any sealant if your patio is sealed. I highly recommend sealing the patio after the acid wash and it will definitely help with future staining". Check out muriatic acid here and here.

hoto of spongy moth caterpillar poop
Some cleaner items New York residents have tried to remove caterpillar poop include CLR, Magic Erasers, and Bar Keeper's Friend (TSM Poughkeepsie/Lowes)

Other Options to Remove Caterpillar Poop Stains

Other commenters suggesting trying CLR (Calcium Lime Rust) cleaner, Mr. Clean Magic Erasers, Dawn dish detergent ("seems to remove everything", came the quip). or the classic Bar Keeper's Friend cleanser.

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Between the leaf damage and the patio stains, the invasive caterpillars are certainly leaving their mark on the New York landscape. Luckily, most trees will rebound from their defoliation, and now, their "markings" will soon be a distant memory as well.

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Gallery Credit: Will Phillips

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