Green spruce aphid
Unlike most aphids which are active during spring and summer, the green spruce aphid is most active during winter. It can cause needle drop on spruce trees (Picea species).
Scientific name: Elatobium abietinum
Plants affected: Picea species especially Picea abies (Norway spruce or Christmas tree), Picea sitchensis (Sitka spruce) and Picea pungens (blue spruce)
Main symptoms: Pale blotches and small green aphids on foliage overwinter. Heavy needle drop in spring
Most active: October to March
What is green spruce aphid?
Green spruce aphid is a sap-sucking insect that feeds on spruce trees (Picea species) often causing needle drop.
- Green spruce aphid is up to 2mm long, dull green with dark red eyes
- It is most likely to be seen on spruce trees during late autumn to spring
- Old needles develop a pale mottled discolouration during the winter and many of these needles fall off in spring
- A black sooty mould may be noticeable on stem joints
- New growth produced in spring is unaffected, and its bright green appearance often contrasts strongly with the discoloured and sparsely foliated older stems
Check spruce trees frequently from summer to spring so action can be taken before a damaging population has developed. Little can be done to deal with aphids on tall trees as treatment is only likely to be successful if the entire plant can be reached. 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 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.
It can take several years for a badly damaged tree to regain an attractive appearance
- Where possible tolerate populations of aphids, although small populations of this species can cause extensive needle drop.
- Use finger and thumb to squash aphid colonies where practical
- Encourage ‘aphid predators’ in the garden, such as ladybirds, ground beetles, hoverflies, parasitoid wasps and earwigs. Be aware that in spring aphid populations often build up before natural enemies are active in sufficient numbers and then give good 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.
Little can be done to deal with aphids on tall trees as treatment is only likely to be successful if the entire plant is sprayed. To prevent damage it may be necessary to spray the trees as soon as signs of aphids are seen. For the green spruce aphid, however, it is late August or September, with a further treatment on a mild dry day in early February
- 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 aphids. These pesticides have a very short persistence and so may require reapplication to keep aphid 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
Pesticides for gardeners (pdf document)
- The green spruce aphid differs from most other aphids by being most active from autumn to spring, instead of spring and summer
- The summer is spent as non-feeding nymphs
- This aphid can be particularly damaging in mild winters, which enable it to breed more rapidly
- Aphids should not be confused with other insects known as barklice or psocids. These insects are usually brown and often move rapidly over the plant, aphids usually remain fairly stationary. Psocids feed on algae and fungal spores and may be numerous on trees affected by sooty mould
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