Cottonwood Leaf Rust: Same Disease, Same Advice

Cottonless Cottonwood Dropping Leaves in Clusters? It’s Rust.

Your cottonless cottonwood shows the same symptoms: leaves falling in clusters (some green, some dead), blackened twig tips, white dots on black areas. This is cottonwood leaf rust, not aphids. The rust fungus cycles between cottonwood and a conifer alternate host.

What to Do

• Rake and destroy all fallen leaves to cut spore load for next year.
• No fungicide works for yard trees.
• Tree won’t die, but repeated infections slow growth.

See detailed info here.