Eucalyptus Sucker, or psyllid, is a species of insect closely related to aphids. They feed in the same way, by sucking the sap from plant leaves. They are also referred to as 'jumping plant lice'; because they have long hind legs that they used to jump from leaf to leaf, similar to a leafhopper. They're an invasive species, originating in Australia.
A good food resource for predatory insects.
Sucker leave sticky honeydew on plants.
This species is easily recognised in the UK as it's the only psyllid belonging to the Ctenarytaina genera in the country. Adults are pale yellow, reaching 4mm big. Their head-plate, or dorsum, are dark brown. Nymphs look like mini versions of the adult, are tiny (1.5mm), and wingless. They become covered with copious amounts of honeydew, making the infected site prone to black sooty mould. Eggs are even smaller and pale yellow. Eggs are laid singularly so are difficult to see with the naked eye.
You may see these small insects dotted about areas of new growth on your plant. Leaves may be covered in clear sticky honeydew, or, possibly a black sooty mould. Although unattractive, these insects will not be detrimental to the plant and are tolerable.
California, Sri Lanka, South Africa, South America and are widespread across Europe.
If infestations are heavy, it's advised to pick off infected leaves. Use these pests to attract natural enemies to your garden, such as hoverfly larvae. There are organic pesticides containing natural pyrethrum which can be effective against suckers, these must be applied on the effective site over a series of applications. Please read instructions prior to application.
Chemical treatment is usually unnecessary as the damage caused bu this insect is normally only minor.