Scale

(Question)

How should I go about getting rid of scale on my euonymus plant? I’m pretty certain it is scale. Should I start treating it now while it is still cool outside. Or should I wait until it warms up more? Thank you for your answer

(Answer)

Euonymus Scale (Unaspis euonymi) is the most common and most serious pest found on euonymus. Initial symptoms of euonymus scale infestation are yellow spots on leaves. The scales are typically concentrated along the stems and lower leaf veins of the plant. In the case of heavy infestations, plants look water stressed, leaves develop yellow spots and fall off, and twigs and limbs may die. Scales are small (less than 1/8 inch long), and with close examination you can see the white, longitudinal ridges of the males and the dark oystershell shaped females. The scales spend almost all of their life feeding on the same spot while being protected by their hard covering. A scale cover will remain on the plant even after the insect has matured or died.  Give your plants a thorough examination to ensure that it is scale before you treat the problem.

There are several things that you can do to protect your euonymus from scale. The easiest thing to do is to buy resistant varieties. There are several cultivars available that have been bred to be resistant to this dreaded pest. If yours are past the point where they can be saved consider replacing them with these.  Next, ensure that you retain plant health by watering and fertilizing the plants appropriately all year long. Pruning  plants to ensure good air circulation is another way to ensure plant health.

If a scale problem is found early, minor scale can be manually removed with a soft brush or toothbrush. By rubbing the scales off of the plant, their mouthparts are injured and they are unable to re-infest the plant.If your problem is further along, you can try suffocating the scale with horticultural oil, available at any nursery or plant store. Ideally, an oil spray should be applied during the dormant season (winter to early spring) to kill overwintering scales. Repeated applications may be necessary with heavy infestations and should be targeted when the crawlers are most active. For heavy infestations on E. japonicus and E. fortunei , plants may be cut to the ground in early to mid-spring. You would then remove and destroy all of the infested plant material.

Here is some additional information on controlling euonymus scale:

http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/insects/scale/euonymus-scale.aspx

 

Euonymus adds so much to any garden, all year long, and with some good initial plant selection and year round care, the problem is quite manageable.