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
Small sap sucking hemispherical scale insects can encrust the leaves and stems of a wide range of glasshouse plants.
Hemispherical scale (Saissetia coffeae) on Climbing fern (Lygodium circinatum)
There are many types of scale insects encountered by gardeners, they are sap sucking true bugs. Hemispherical scale is a dark brown, round, convex scale insect up to 4mm in diameter. It is found on the leaves and stems of indoor and glasshouse plants such as ferns, cycad, ornamental asparagus, Stephanotis and many others. It produces honeydew and breeds throughout the year.
This scale insect rarely causes direct damage to plants. Apart from the presence of the insects the main symptom is the presence of honeydew on which sooty mould can grow.
It can appear similar to other diaspid scales.
Hemispherical scale insects can be difficult to control; replacing severely infested plants should be considered.
Well-tended healthy plants are able to tolerate infestations. Physically squashing or removing scales may control light infestations.
Pesticides for gardeners (Adobe Acrobat pdf document outlining pesticides available to gardeners)
Biological control suppliers (Adobe Acrobat pdf)
Hemispherical scale feed by sucking sap from the leaves and stems of various glasshouse plants. Scales are named for the waxy shell-like casing which covers most of their body. When mature, the females lay their eggs under the protection of this shell.
All hemispherical scales are female and reproduction is continuous throughout the year and entirely parthenogenetic. The eggs hatch into small active nymphs, known as crawlers, which wander over the plant surface until they find a suitable place to feed. They then become immobile and begin to produce their characteristic scale covering.
Infestations of scale insects are spread by the crawler stage, which may travel quite long distances before stopping to feed, and which can be spread by wind currents.
Chemical labels explained
Chemicals: using a sprayer
Chemicals: using safely and effectively
Chemicals: storing and disposing safely
Horse chestnut scale
Protect your garden
RHS statement on pesticides in horticulture
Scurfy rose 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.
We're a UK charity established to share the best in gardening. We want to enrich everyone's life through plants, and make the UK a greener and more beautiful place.