Join the RHS today and support our charitable work
Keep track of your plants with reminders & care tips – all to help you grow successfully
RHS members get reduced ticket prices
RHS members get free access to RHS Gardens
Free entry to RHS members at selected times »
Reduced prices on RHS Garden courses and workshops
020 3176 5800
Mon – Fri | 9am – 5pm
Help us achieve our goals
Join the RHS today and support our charity
Euonymus scale has become widespread in England and can cause severe dieback on evergreen Euonymus species.
Euonymus scale (Unaspis euonymi) on spindle (Euonymus europeus)
Euonymus scale is a small sap-sucking insect that infests the stems and foliage of Euonymus. It became established in Britain on the south coast of England during the 1950s. It spread along the south and east coasts and is now found in gardens throughout England. This insect has a soft flattened body that is covered by a shell or scale. There are many types of scale insects encountered by gardeners.
Heavily infested plants develop a yellowish mottling on the foliage and this may be followed by extensive leaf fall and dieback.
Male and female euonymus scales differ in appearance. The males are mainly on the foliage and are covered with narrow white elongate scales that are 2mm long. The females mainly occur on the stems and are covered with blackish brown pear-shaped scales up to 3mm long.
The most susceptible host plant seems to be Euonymus japonicus but other evergreen and deciduous spindles can also be affected. Heavily infested plants may lose most of their foliage and suffer dieback. These plants sometimes recover but replacement may be necessary.
The native kidney spot ladybird, Chilocorus renipustulatus, specialises in feeding on scale insects and can naturally colonise infested plants reducing infestations.
The best time to control scale insects is when the more vulnerable newly hatched nymphs are present. As this insect has two generations a year, the best times for treatment are in June and early September. Dead scales often remain attached to the plant but new growth should stay clean if the treatment has been successful.
Pesticides for gardeners (Adobe Acrobat pdf document outlining pesticides available to gardeners)
Euonymus scale has two generations a year. The females deposit their eggs underneath their bodies. Nymphs of the first generation emerge in June and crawl over the plant in search of suitable places to feed. They reach the adult stage in mid-late summer and lay eggs that hatch in early autumn.
Chemical labels explained
Chemicals: using a sprayer
Chemicals: using safely and effectively
Cotton stringy scale
Horse chestnut scale
RHS statement on pesticides in horticulture
Scurfy rose scale
Why has my tree or shrub died?
Woolly vine or currant scale
the RHS today and get 12 months for the price of 9
RHS members can get exclusive individual advice from the RHS Gardening Advice team.
The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.