Euonymous Scale

Characteristics

Euonymus scale is a small sap-sucking insect that feeds on the stems and foliage of euonymus plants. Euonymus scale has three stages of development: egg, nymph or crawler stage, and an adult stage. As a nymph, the scale is mobile, crawling around looking for new places to feed. When mature, it produces a protective covering over its body.

Euonymus scales overwinter as mature fertilized females. They are grayish - brown coloured. The males are smaller, narrower and white. In the spring, eggs are laid underneath the protective scale of the female. In May to mid July newly hatched nymphs will begin to feed on the euonymus. 

Signs & Symptoms

Euonymous scale is often over-looked until serious damage occurs. It is a good idea to examine the leaves in June and July for feeding or sucking injury.

Small, white bumps will be visible on leaves and stems of the plant. Leaf drop and death to the tree or plant may occur. Euonymus in direct sun near buildings tend to be more prone to attack. These areas often have poor air circulation, high temperatures, and low soil moisture.

Treatment & Recommendations

Where possible, prune out and destroy infested branches before crawlers emerge. When planning a chemical control for scales, remember that insecticides have difficulty penetrating the adult shell once it has formed. Strategies must be aimed at the overwintering adult and the crawler.

Applying Dormant oils will provide good control for the overwintering female scales as it will smother the insects. This is used to control the population.

Talk with one of our qualified arborists about plant health care applications for your Euonymous.