Bugs Eating a Maple Tree

Many different pests attack maple trees. Some insects only make maples look unattractive, while others can severely disfigure or even kill the tree. The method of treatment varies depending on the type of insect. Recognizing what type insect infest the tree is the first step to treatment.

Types

Cottony maple scales are flattened, oval-shaped brown insects without any noticeable moving parts. They range in size from 0.25 to 0.38 inches. Maple spindle, erineum or felt galls are tiny eight-legged mites that are closely related to spiders, while eyespot midge galls are tiny flies. Woolly aphids are waxy, pear-shaped insects that are usually less than 0.125-inches long.

Effects

Cottony maple scale insects insert their mouthparts in twigs and branches and suck out plant juice. Large infestations can kill branches or entire trees. Gall insects burrow between the upper and lower surfaces of leaves to feed and lay their eggs, creating irregular bumps or growths on leaf surfaces. Woolly aphids feed on plant tissue from the foliage and roots, resulting in yellowing, leaf distortion and dieback.

Prevention/Solution

Cottony maple scale populations are managed using horticultural oils, insecticidal soaps or traditional pesticides. Gall midges and mites do not harm maple trees, so no control is necessary. Biological organisms such as lady beetles and lacewings usually keep woolly aphid populations under control, but insecticides will reduce large infestations.

References

• Ohio State University: Cottony Maple Scale and Its Management
• University of Kentucky: Common Maple Galls
• University of Minnesota: Woolly Aphids on Trees and Shrubs