Q • My oak trees have more large galls than I’ve ever seen on them, and I’m worried about their health. What can I do about ...

Galls are abnormal growths and can be caused by a variety of different organisms, including insects and mites, and occasionally nematodes, fungi, and bacteria.

The galls are filled with fibers and small seed-like capsules, which is why they are also known as oak seed galls. Each of these “seeds” contains a single wasp larva.

"I used to have a whole set of these, with Fijian currency on them. It's for tourists, so they have some hope of not getting ...