Round Mites & Pests of Japanese Maples
- The maple mite is a common pest of nursery-grown maple trees, as well as maples in the landscape. Resembling the two-spotted spider mite, the maple mite is spherical and is usually red or pink in color. Maple mites damage maple trees by feeding on the undersides of leaves, which causes stippling to appear. Infested maple trees may also develop yellow and distorted leaves. Maple mites may be controlled by spraying your Japanese maple with a hard stream of water to remove mites from the tree. Insecticidal soaps and horticultural oils are also effective in controlling spider mites.
- Aphids are common pests of all maple trees, as well as other ornamental plants, trees and shrubs. This tiny pest damages maple trees by feeding on their leaves with piercing mouthparts. It sucks sap from the leaves, which often causes them to appear speckled and wilt. Dieback may also occur from aphid feeding, and affected leaves often curl. The presence of sooty mold is a sign that aphids have infested your Japanese maple tree. Sooty mold is caused by the sticky substance produced by aphids, which is known as honeydew. Sooty mold is often unsightly, covering the leaves and branches of the tree. Aphids are controlled by many types of predatory insects that feed on them, including green lacewigs, parasitic wasps and flower flies.
- Scales are a common maple tree problem and are a serious pest of many other ornamental trees and shrubs. The cottony maple scale is the most common on Japanese maple trees and is characterized by the cottony patches left on the branches of host trees. Scales damage trees by feeding on the foliage, causing stippling of leaves, leaf yellowing, dieback, premature defoliation and plant death. Scale insects excrete honeydew like aphids and also cause sooty mold to develop on host trees. Prune out branches infested with scales if possible and destroy infected plant debris. Avoid using fertilizers with high levels of nitrogen, as these products promote scale insect infestations.
- Japanese maples in failing health often suffer from infestations of boring insects. Boring insects such as weevils, beetles and caterpillars damage trees by chewing the plant tissue and tunneling into the heart wood. Larvae of boring insects tunnel in roots, shoots and branches of maple trees of all sizes. Detecting boring insects is often difficult, and trees may have suffered serious damage by the time symptoms appear. Pheromone traps are available for the control of boring insects. Repeated infestations often require insecticidal sprays for control. Contact your local extension office for a list of products recommended for control of these damaging pests in Japanese maple trees.
