Scales on Fire Bush

Asked February 29, 2020, 6:26 PM EST

I have 4 (used to be 5) Fire Bush ( I think Euonymus Alatus) plants which have been attacked by scales. What is the best method to treat the scales? When is the best time to apply the treatment? Thank you. Joe

Harford County Maryland

3 Responses

Euonymus alatus can be subject to several different types of scale insects. Control depends upon their life cylce. Please send us photos so we can see what you are dealing with. Send photos of the whole shrub, around the base of the plant, and affected stems as the scale overwinters on the stems.

Marian

Hello Joe,

It's difficult to see any scale in the photos; at the least, there does not appear to be a major infestation, though perhaps they are simply out-of-focus. Candidates could be Winged Euonymus Scale or Japanese Maple Scale (which feeds on an array of shrubs and trees). Adult covers can be as small as about 2mm long, so they are very difficult to spot among bark ridges. For Winged Euonymus Scale, eggs overwinter under their parents' covers, and there is only one generation per year.

There are a couple of approaches to consider: removal or treatment. We suggest removing the Burning Bush due to it being an invasive species (birds eat the berries and seedlings can take over woodlands, out-competing the wildflowers) and replacing them with another shrub. One option is our native Sweetspire (Itea virginica) as it turns a beautiful mix of red, orange, and burgundy/maroon in autumn, often lasting longer than Burning Bush's color. Fothergilla (either F. major or F. gardenii) is another regionally native shrub with showy spring flowers, clean foliage, and showy autumn colors.

If trying treatment, you can use an oil-based spray to smother the young ("crawlers"), which won't hatch until June (for both scales). Dormant oil, which is a more concentrated spray (and sold in this form), could be tried during mild weather before the leaves emerge to smother the adults. Shrubs with mild infestations typically aren't negatively affected, though stress factors such as drought stress can tip the balance toward leaf yellowing or defoliation.

Miri