Aphids are sap-sucking true bugs. They range in size from 1 to 7 mm (¼ in 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 (around1.5-1.8 mm long) with red eyesis that feeds on spruce trees (Picea species) often causing needle drop.

• Green spruce aphid is up to 2 mm 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 and it is not unusual to have some of these animals in a healthy balanced garden ecosystem. On tall trees aphids, where management is impractical, aphids can be considered part of the biodiversity they support. The presence of this aphid should not affect long term health of your spruce tree, however, 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
• 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
• Check spruce trees frequently from autumn onwards so action can be taken before a large population has developed
• Use finger and thumb to squash aphid colonies where practical