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Hellebore aphid

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last updated Jun 10, 2010
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Hellebore aphid (Macrosiphum hellebori) on Hellebore (Helleborus sp.). Credit: RHS/Entomology.

One of the most important pests of hellebores is a sap feeding aphid or greenfly. It can cause unsightly, sooty mould on the leaves and flowers.

What is hellebore aphid? Back to top

A sap-sucking aphid or greenfly that infests the flowers and foliage of hellebores in the spring.

Symptoms Back to top

  • Whitish-green aphids, 2-4mm (about 1/8in) long, sometimes form dense colonies on the underside of hellebore leaves and flowers in early spring.
  • The sugary honeydew they excrete can also encourage unsightly sooty moulds on the foliage.

Control Back to top

  • Aphids can be controlled by using the systemic insecticides thiacloprid (Provado Ultimate Bug Killer concentrate or ready to use), acetamiprid (Scotts Bug Clear Ultra concentrate or Bug Clear Ultra Gun ready to use) or thiamethoxam (Westland Plant Rescue Bug Killer Ornamental Plants).
  • Pesticides containing deltamethrin (BayerSprayday Greenfly Killer) or lambda cyhalothrin (Westland Plant Rescue Fruit & Vegetable Bug Killer) can also be used for aphid control.
  • If plants are in flower, spray in the evening when bees are not active.


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

Biology Back to top

  • Although this aphid can be present on hellebores all year round, noticeable infestations only occur in early spring at flowering time.
  • It is possible this aphid may also be responsible for spreading the serious virus disease known as hellebore black death.

Quick facts

Common names Hellebore aphid
Scientific names Macrosiphum hellebori
Plants affected Hellebores (Helleborus species)
Main symptoms Whitish green aphids cluster on the flowers and foliage, which is sticky with honeydew excreted by the aphids
Most active March-April