How to Get Rid of Scale on Euonymus Shrubs

All About These Pests and The Pruning, Oils and Insecticides You Will Need

Scale on Euonymus Shrubs
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Euonymus, often called spindle or spindle tree, is a genus of flowering plants in the staff vine family, Celastraceae. They are mostly native to East Asia, extending to the Himalayas.

Euonymus comes in a wide variety of colors, shapes & sizes - both evergreen & deciduous varieties are available readily at nurseries & garden centers. Some Euonymus varieties, such as the Dwarf Burning Bush, have seasonal coloration that provides a different look from season to season - while others, like the Green Boxleaf Euonymus and Golden Euonymus, provide consistency year round.

You will find that some of our Euonymus selections are good for use as groundcovers, while others make excellent hedge choices.

Euonymus Scale

One type of scale that attacks euonymus shrubs (especially Euonymus japonica) is the euonymus scale (Unaspis euonymi). This is an armored type of scale that comes in two colors: males are white and females are brown. Both suck on plant tissue which can cause damage. They also drop honeydew, a sticky substance that can cause sooty mold to form.

Armored scales live under a protective covering and feed on plant juices. Euonymus scale appears on the stems and leaves of infested plants as tiny white lines 1/16 inch long or as slightly larger, swollen brown lumps. Heavily infested plants may be coated with tiny white lines, particularly on stems and leaf veins. This coating of white lines is the most easily identifiable symptom. White or yellow spots appear on leaf surfaces in response to scale feeding.

Other varieties of Euonymus are susceptible to scale: Wintercreeper (Euonymus fortunei), European euonymus (Euonymus europaeus), pachysandra (Pachysandra terminalis), bittersweet (Celastrus scandens)

Euonymus scale spends the winter as a mated adult female that then lays eggs in the spring. These eggs hatch into tiny immature scales called crawlers that, for a brief period, move along stems and leaves until they become immobile, grow a protective covering, and begin to feed.

The first crawlers hatch and are active from late May to early June. Another generation of crawlers is active again from late July to August.

It is not the soil that is infested. The scales need a branch to get established. The females have their young under their coverings, so it can be hard to take care of them for good.

Getting Rid of Scale on Euonymus Shrubs

First, you can try cutting out and destroying infected branches. You can disregard the pruning rule of 1/3 in this case and cut it back a lot, though it is best not to do it completely to the ground.

If you can find it, there's a type of lady beetle (Chilocorus kuwanae) that can help control the euonymus scale population.

Since scales are armored, it can be hard for insecticidal soap to get through, so you may have to apply it several times to control the infestation.

You can also try using horticultural oils. Some are used in winter while dormant and others can be used in spring and summer. Check the directions to make sure you have the kind you want.

You may have to resort to insecticides. I would check with your local extension office to see what is legal and recommended for your area, as it can definitely vary from state to state.