Galls of other shapes are seen less frequently on other types of maples. Galls are not serious, so chemical controls are not suggested. Crimson erineum mite is usually found on silver maple and causes the formation of red fuzzy patches on the lower leaf surfaces. The problem is not serious so control measures are not suggested. Aphids infest maples, usually norway maple, and may be numerous at times.
High populations can cause leaf drop.
Another sign of heavy aphid infestation is honey dew on lower leaves and objects beneath the tree. Aphids are controlled by spraying or they may be left alone. If not sprayed, predatory insects will bring the aphid population under control. Chemical controls include sprays of Diazinon and malathion. Boxelder bug infests boxelders, primarily the female trees.