Oleander scale

The small whitish oleander scale can affect a variety glasshouse plants, including oleander, dracaena, palms and ornamental asparagus.

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Oleander scale (Aspidiotus nerii) on Oleander (Nerium oleander)

Quick facts

Common name Oleander scale
Scientific name Aspidiotus nerii
Plants affected A variety of glasshouse plants
Main symptoms Whitish 2mm diameter scale insects on leaves and stems
Caused by Sap sucking scale insects 
Timing All year

What is oleander scale?

Oleander scale is a sap sucking true bug that appears as a flat, oval, whitish-brown insects on leaves and stems of indoor plants. The whitish covering of the insect is waxy and repels liquids. The adults reach up to 2mm long, the immature stages (crawlers) are much smaller. It does not produce honeydew and breeds throughout the year. It is one of several species of scale insects encountered by gardeners.

Symptoms/

Populations of oleander scale are characterised by encrustations of the 2mm diameter scales on leaves and stems of glasshouse plants. Common host plants include Acacia, Asparagus plumosus, azalea (Rhododendron), Cyclamen, Dracaena, Nerium oleander (oleander) and palms. Heavily affected plants can lack vigour. It can appear similar to other diaspid scale insects.

Control

Check susceptible plants frequently so action can be taken before a damaging population has developed. When choosing control options you can minimise harm to non-target animals by starting with the methods in the non-pesticide control section. If this is not sufficient to reduce the damage to acceptable levels then you may choose to use pesticides. Within this group the shorter persistence pesticides (that are usually certified for organic growing) are likely to be less damaging to non-target wildlife than those with longer persistence and/or systemic action.
Light infestations are of little consequence and can be tolerated. Note that dead scales can remain firmly attached to the plants. The success of any treatment can be gauged by the extent to which new growth remains free of scale insects.

Non-pesticide control

  • Where possible tolerate populations of scale insects. Well-tended healthy plants are able to tolerate light populations of these insects and so they do not necessarily require control
  • It can be worth considering replacing heavily infested plants
  • Adult scales and egg masses can be removed when seen but this may not reduce large populations


Pesticide control

The RHS believes that avoiding pests, diseases and weeds by good practice in cultivation methods, cultivar selection, garden hygiene and encouraging or introducing natural enemies, should be the first line of control. If chemical controls are used, they should be used only in a minimal and highly targeted manner.

Spraying works best against the more vulnerable newly hatched scale nymphs,  this scale breeds all year round and so there is no ideal time to spray.
  • Organic sprays, such as natural pyrethrum (e.g. Bug Clear Gun for Fruit & Veg, Neudorff Bug Free Bug and Larvae Killer), fatty acids (e.g. Doff Greenfly & Blackfly Killer) or plant oils (e.g. Vitax Plant Guard Pest & Disease Control, Bug Clear for Fruit and Veg) can give good control of scale insect nymphs. These pesticides have a very short persistence and so may require reapplication to keep scale numbers in check. Plant oil and fatty acid products are less likely to affect larger insects such as ladybird adults 
  • Plant invigorators combine nutrients to stimulate plant growth with surfactants or fatty acids that have a physical mode of action (e.g. Ecofective Bug Control, RHS Bug and Mildew Control, SB Plant Invigorator and Westland Resolva Natural Power Bug & Mildew). These are not considered organic
  • More persistent contact-action insecticides include the synthetic pyrethroids lambda-cyhalothrin (e.g. Westland Resolva Bug Killer), deltamethrin (e.g. Provanto Ultimate Fruit & Vegetable Bug Killer, Provanto Sprayday Greenfly Killer) and cypermethrin (e.g. Py Bug Killer)
  • A systemic containing the active ingredient Flupyradifurone (Provanto Smart Bug Killer) is available for use on ornamentals and selected edibles
  • The systemic neonicotinoid insecticide acetamiprid (e.g. Bug Clear Ultra) is also available
Follow label instructions when using pesticides. Plants in flower should not be sprayed due to the danger to bees and other pollinating insects. Inclusion of a pesticide product does not indicate a recommendation or endorsement by RHS Gardening Advice. It is a list of products currently available to the home gardener.

Downloads

Pesticides for gardeners  (pdf document)

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