Question
We have lived in our house for more than 20 years and the sugar maple tree next to our driveway has never leaked.  It is a very healthy looking tree.  This year it started leaking clear and brown sticky liquid - I assume sap.  The cars are covered with it every morning.  People ask us all the time "did someone spill coffee on your car?"  We are in the north suburbs of Chicago and we had the cicadas this year, but only a few by our house.  Any suggestion on what to do?

Answer
Check to see if the leaves are sticky. If so the problem is an insect called aphids. These soft bodied insects suck the plant juices and excrete a substance called honeydew, a liquid high in sugar content. A black sooty mold will grow on the honeydew turning things a black color. To control the honeydew you will have to spray the aphids with an insecticide. Check with your local nursery for a systemic insecticide for aphids on trees. There are some that can be applied to the ground and watered in and the tree takes these to the leaves.
If the leaves are not sticky check the small branches for cuts that could have been made by the cicadas. They make slits in the bark of small branches to lay eggs in and these slits maybe leaking sap. If so there is nothing that can be done to stop this now. The good news is that cicadas life cycles are long and there will more than likely not be a problem next year.