Scale on My Silver King Euonymus

Yarmouth Port, MA

Hi, I have scale on my Silver King. It is pretty badly infested. I sprayed horticultural oil on Sunday. How often should I do that and is there anything else I should be doing? This site is great. I know I am going to learn a lot. Thanks to Candyce for the warm welcome!

Mid-Cape, MA(Zone 7a)

Hi CapeCodCasper:
Sorry no one has been able to answer your question yet. Here is some information that I copied from the Clemson site. I think you did the right thing by spraying horticultural oil first.
I have several euonymus in my garden. I'm glad to have this information brought to my attention.
PS: I also live in Yarmouthport.


"Several species of scale are pests on euonymus. Scales are unusual insects in appearance. They are small and immobile, with no visible legs. Scales vary in appearance depending on age, sex and species. They feed on sap by piercing the leaf or stem with their mouthparts and sucking.

Euonymus scale (Unaspis euonymi): This is the most common and most serious pest found on euonymus. The protective armor covering of an adult female euonymus scale is dark, oyster-shaped and about 1/16-inch in length. Adult males are very small, winged insects that leave their narrow, white armored covering for mating. The eggs laid by the female are yellow and found beneath the female’s covering. When the eggs hatch, the crawlers (immature forms) move around before forming their own protective covering. Males typically outnumber females. With a heavy infestation, clusters of white males can be easily seen on leaves and stems. Initial symptoms of euonymus scale infestation are yellow spots on leaves. With a heavy infestation, branches and possibly the entire plant may die.

Prevention and Control: The following Euonymus species are resistant to euonymus scale: E. alatus ‘Compactus’ and E. fortunei ‘Acutus.’ Consider using these in new plantings. Euonymus scale is difficult to control. With light infestations, scale can be scraped off by hand and destroyed. Pruning out heavily infested branches is helpful. Avoid using insecticides unless the plant is very valuable and in serious danger from scale. Insecticides will often kill the naturally occurring enemies of scale.

Adult scales are relatively protected from insecticides by their waxy covering. Their immature forms, called crawlers, are susceptible, however. Horticultural oil (Bonide All Season Spray Oil, Ferti-lome Scalecide, Green Light Horticultural Oil Spray, or Ortho Volck Oil Spray) can be used as a dormant spray before new growth begins in the spring. It kills many adults and eggs by smothering them. Spray again when crawlers are present in the spring.

Monitor the crawler emergence with sticky cards, double-faced tape wrapped around a branch, or by putting an infested shoot or leaf into a baggie and watching for crawler movement. Crawler activity often coincides with the flush of new plant growth in the spring. However, some scale species may have overlapping generations with an extended crawler emergence period, such as along the coast.

If insecticides are necessary, the following are effective against crawlers: acephate (Ortho Japanese Beetle Killer), malathion (Ferti-lome Mal-A-Cide or Hi-Yield Malathion Insect Spray), cyfluthrin (Bayer Advanced Garden Power Force Multi-Insect Killer), and carbaryl (Sevin 50WP or Ferti-lome Carbaryl Spray). Make sure that crawlers are present before using them. Apply three sprays at 10-day intervals. As with all pesticides, read and follow all label instructions and precautions."



Yarmouth Port, MA

Hello neighbor! Thanks so much for taking the time to give me that info. I have spayed it twice with the oil and that seems to be helping a great deal. Did you enjoy that thunder? Wish it gave us more rain. I am new to this site and am amazed at the information here. Thanks so much for all your help.

Mid-Cape, MA(Zone 7a)

Hi Casper--glad that the oil seems to be helping. I'm going to use it if I find scale when I return home. I've been gone for a week in California, where the summer weather couldn't be more different! Sorry I missed the T-storms.
Keep asking questions! We all learn so much from the responses. Tell us more about your gardens.

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