Something is dripping on our cars – is a tree the culprit?

Q: On our condominium property a homeowner is complaining of something dripping onto her car from trees. There is a red maple and a pine tree nearby. Could both of these trees be the culprit? We really don’t want to take down a healthy maple. 

A: Liquid dripping from trees is not usually from the tree itself. It is probably undigested plant sap (honeydew) excreted by insects that feed on the tree. In such cases controlling the insects will solve the problem. The most effective insecticide for this is imidacloprid. It is poured on the soil around the base of a tree and taken up to the leaves, where it kills any sap-sucking insects. Read and follow the directions, and do not use it when the tree is blooming.