Eucalyptus sucker

Eucalyptus is often affected by eucalyptus sucker. Any leaf damage caused is not usually serious and can be tolerated.

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Eucalyptus sucker (Ctenarytaina eucalypti) on eucalyptus

Quick facts

Common name: Eucalyptus sucker
Scientific name: Ctenarytaina eucalypti
Plants affected: Eucalyptus
Main symptoms: Insects on the shoots and sticky honeydew
Most active: Spring and summer

What is eucalyptus sucker?

The psyllids or plant suckers are a group of sap sucking true bugs (Hemiptera). There are more than 40 species found in Britain.

Eucalyptus sucker feeds on Eucalyptus they are similar in appearance to aphids and up to 2mm long, with grey and orange-yellow nymphs and darker adults. Both adults and nymphs can be found clustered on the shoot tips during the summer.

This Australian insect became established in Britain during the 1920s and is now of widespread occurrence in the UK on Eucalyptus species.  

Symptoms

Shoots where eucalyptus sucker is feeding are often sticky with honeydew and on which sooty moulds can grow. This insect overwinters as adults, they lay eggs on shoot tips from February onwards. There are two or three generations a year. 

Control

The damage this insect causes is usually minor and treatment is not often necessary. This is fortunate as large trees cannot be effectively treated.

Check Eucalyptus frequently so action can be taken before a damaging infestation 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.

Non-pesticide control

  • Often suckers do not affect the growth or vigour of plants and so can be tolerated
  • Encourage predators and other natural enemies of suckers, in the garden, such as birds, ladybirds, wasps and ground beetles.

 

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.
  • Only small trees can be sprayed, large trees cannot be treated effectively with pesticides
  • 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 suckers. These pesticides have a very short persistence and so may require reapplication to keep sucker 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 against aphids (e.g. Ecofective Bug Control, RHS Bug and Mildew Control, SB Plant Invigorator and Westland Resolva Natural Power Bug & Mildew). These products contain some synthetic ingredients and so 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.

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Pesticides for gardeners (link downloads pdf document outlining pesticides available to gardeners)

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