How To Treat A Quaking Aspen With Leaf Spots

Step 1

Clean the garden bed in fall to remove all fallen leaves and twigs. The fungus overwinters in garden debris.

Step 2

Spray the quaking aspen tree with a fungicide containing mancozeb chlorothalonil. Apply the first treatment when the buds begin to open in spring and repeat every two weeks, unless the fungicide package states otherwise. Fungicide won't cure the disease, but it will protect new foliage from becoming infected.

Step 3

Water the quaking aspen tree at the soil to keep water off the foliage. If you must water overhead, do so in the morning so that the leaves have time to dry before sundown.

Step 4