Aphids are sap-sucking true bugs. They range in size from 1 to 7mm (¼in or less) long. Some aphids are known as greenfly or blackfly, but there are species that are yellow, pink, white or mottled. There are more than 500 aphid species in Britain. Some feed on only one or two plant species, but others can be found on a wide range of plant hosts. Many have lifecycles that involve more than one host plant. Almost any plant can be a host to aphids, including ornamentals, vegetables, fruits, greenhouse plants and houseplants. More information on aphids. 

Green spruce aphid is a small dark green aphid (1.5-1.8mm long) with red eyesis 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

Aphids form the basis of many food chains in the garden and it is not unusual to have some of these animals in a healthy balanced garden ecosystem.  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 management options you can minimise harm to non-target animals by starting with the methods in the non-pesticide control section and avoiding pesticides. Within pesticides the shorter persistence products (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. Pesticide treatments are likely to kill natural enemies and are only likely to be successful if the entire plant can be reached.

It can take several years for a badly damaged tree to regain an attractive appearance

Non-pesticide control

• 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

• Organic sprays, such as natural pyrethrum (e.g. Bug Clear Ultra 2, Neudorff Bug Free Bug and Larvae Killer) or plant oils (e.g. Vitax Plant Guard Pest & Disease Control, Bug Clear Fruit & Veg, Vitax Rose Guard) 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, Growing Success Bug Stop, Rose Clear 3 in 1 Action 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) 
• 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 (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