Oleander scale

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

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

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 glasshouse 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/

Infestations of oleander scale are characterised by the 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 infested plants can lack vigour. It can appear similar to other diaspid scale insects.

Control

Non-pesticide control

Oleander scale is difficult to control. Although scraping the insects off the leaves can help reduce infestations this is unlikely to give good control. It can be worth considering replacing heavily infested plants.

Pesticide control

Oleander scale can be difficult to control with sprays as the waxy covering gives them some protection and the best results are achieved by spraying against the newly hatched crawlers. Heavily infested plants may need several applications.

  • 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 infestation
  • Organic sprays, such as natural pyrethrum (e.g. Bug Clear Gun for Fruit & Veg, Ecofective Bug Killer), fatty acids (e.g. Solabiol Bug Free, Doff Greenfly & Blackfly Killer) or plant oils (e.g. Vitax Organic Pest & Disease Control, Bug Clear for Fruit and Veg) can give good control of scale insects. These pesticides have a very short persistence and so may require reapplication to keep scale insect nymphs in check. Plant oil and fatty acid products are less likely to affect larger insects such as ladybird adults
  • More persistent insecticides include the synthetic pyrethroids lambda-cyhalothrin (e.g. Westland Resolva Pest Killer), deltamethrin (e.g. Provanto Ultimate Fruit & Vegetable Bug Killer) and cypermethrin (e.g. Py Bug Killer)
  • The systemic neonicotinoid insecticide acetamiprid (e.g. Bug Clear Ultra) is also available
    Follow label instructions when using pesticides
  • Inclusion of a pesticide product does not indicate a recommendation or endorsement by the RHS. It is a list of products currently available to the home gardener
  • Do not spray on or near plants in flower due to the danger to pollinating insects

Downloads

Pesticides for gardeners  (Adobe Acrobat pdf document outlining pesticides available to gardeners)


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