Many species of scale insects exist and feed on a wide range of host plants.
When are my trees at risk and what should I look for?
Scale insects are extremely small insects that look quite different from normal insects. They can be difficult to detect if only a few insects are present. As their population grows, they can be detected and can be harmful to the plants’ health.
These insects injure plants as they feed on the plant sap. As they feed, they pierce the plant tissue, removing the sap, resulting in yellowing of tissues. Scale insects can also cause large amounts of honeydew, a sugary waste product, to cover leaves and other surfaces under the area of infestation. A fungus called “sutty mold” will feed on the honeydew and will begin to cover portions of the leaves, giving them a discolored appearance.
Scale insects are divided into two categories: 1. Armored Scales and 2. Soft Scales. Each category has different life cycles and can vary in appearance.
Armored scale insects secrete a thick, waxy cover over the tops of their bodies. They usually spend the winter in the egg stage or as mature females. The eggs will begin to hatch during late May or early June.
Scale insects can be detected by closely watching your trees and shrubs. If detected in its early stages, they can be managed.
Soft Scale insects are usually larger and do not have a protective cover like the armored scale insects. Soft scale insects overwinter as nymphs and the females lay their eggs during late spring. The eggs will hatch later in the year, typically during late June and July.