Hello William,

Maple trees including the red maple (Acer rubrum), are susceptible to a wide range of insect and diseases including eastern tent caterpillar, spongy moth (gypsy moth) and forest tent caterpillar. Read more here: https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=j170

And here: https://www.canr.msu.edu/news/what_is_eating_my_leaves_spring_leaf_eaters_gardeners_should_know

Attached is an article from the University of Kentucky on such problems: http://www.uky.edu/Ag/Entomology/treepestguide/maple.html

It is hard to tell what pest is actually causing the damage to your tree. The Plant and Pest Diagnostic Lab at MSU Extension can give you an in-depth analysis. Learn how to submit a sample or photograph at: https://www.canr.msu.edu/pestid/

You could also consult a certified arborist to learn the cause and a treatment. To find an arborist in your area, go to www.treesaregood.org, the website of the International Society of Arboriculture.

I hope this helps you solve your problem.

Thank you for contacting Ask Extension.