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 folks at Bartlett Tree Experts say the damage is caused by solitary oak leafminer larvae. The miner is the larvae of a moth, Cameraria hamadryadella, that is common on white oaks.

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