Maple Tree Bugs

They provide shade on a hot day, tasty syrup for your pancakes or a splash of bright color against a dull autumn sky. Of the more than 120 species of maple trees (Acer spp.), 13 are native to North America, growing in U.S. Department of Agriculture plant hardiness zones 3 to 9. Just as there is a wide variety of maple tree species and cultivars, there is an equally diverse assortment of insect pests that threaten these trees.

Chewed edges or holes on maple leaves are usually signs of a caterpillar pest. Cankerworms, also known as loopers or inchworms, are green to black moth caterpillars that move along leaves in a looping motion. Yellownecked caterpillars are black with yellow stripes and an orange head. They feed in groups and can completely strip small maple trees of their leaves. Other leaf-eating bugs that infest maple trees include tiny, pear-shaped aphids, black and red boxelder bugs and bronze-colored Japanese beetles.

Some maple bugs remain hidden within the tree but the damage they cause soon becomes evident. The flatheaded appletree borer, Asian longhorned beetle and ambrosia beetle are particular pests of maple wood. The larvae of these beetles tunnel through the hardwood of the tree causing girdled trunks and canopy dieback. While it may be impossible to see inside your tree to identify the pest, exit holes in the trunk or on branches, along with small toothpicklike protrusions of beetle waste jutting out from the bark, are clear signs of a wood boring pest.

Wood boring insects typically attack already damaged or unhealthy trees. Keep your maple healthy by appropriate watering and fertilizing for the species or cultivar, pruning dead or damaged limbs and protecting the trunk from injury by lawn equipment. Chemical treatments are rarely needed and must be repeated indefinitely. If your maple tree is heavily infested and showing severe damage, it is best to have it removed so nearby trees don't become infested.