Oak Leaf Miner – Identification and Control

Q: These diseased areas appeared on most of our oak trees. The trees have been healthy for the 40 years we’ve lived here. I think some of the trees are also affected down the street. From the pictures, do you have any idea what’s the problem?

A:  The damage is not a disease. It is caused by solitary oak leafminer larvae. The miner is the larvae of a moth, Cameraria hamadryadella, that is common on white oaks.

Once an egg is laid on a leaf and subsequently hatches, the miner bores into the leaf and feeds on tissue between the upper and lower surfaces of the leaf.

Rake fallen leaves promptly and destroy them to destroy pupae in cocoons. If the problem comes back next year, consult an arborist about treatment.

Usually, as the miner population grows, the number of beneficial insects that attack the miner increases as well. Unless the tree is young and a favorite specimen, control is rarely needed.

Oak leaf miner damage. Numerous black dots are miner droppings in the leaf.

Oak leaf miner exposed. See other miners still in the leaf above this one.