Question
I have a 7 year old maple tree in new jersey which appears to be very healthy. It is October, and I have just noticed that on the back of all the leaves there are many tiny pests that look like tiny striped worms coiled up and inside a thin white pod. They easily scrape off and dont move when the pod is broken. Any idea what this is and if I should be worried?

Answer
These are insect galls. The adult insect lays its eggs on the leaves and secrete a chemical that causes the leaf cells to expand and forms a gall over the egg. The eggs hatch and the larvae feed in the gall until they mature and become adults. The leaf gall insects cause no real health problem to the tree. The population of the these insect will vary greatly from year to year so no treatment is needed--next year chances are you will see little signs of galls. I would not worry about these leaf galls.