How to recognise it
These are small (2-3mm long), sap feeding insects. The nymphs, which are known as ’suckers’, have flat bodies with prominent eyes and growths on their sides which will eventually develop into wings. The winged adults can both fly and jump. The different species have varying colourings and some excrete a white wax which can initially be mistaken for a woolly aphid infestation.
Lifecycle
The lifecycle varies between species, but the eggs hatch from spring onwards. The nymphs go through several developmental stages before become adults. They overwinter either as eggs or as adults.
Why it’s a problem
Psyllids feed on the sap of plants, which can distort young buds and shoots. The resulting flowers can be damaged as a result and they can fail to open altogether, with the knock on effect of reduced cropping from affected fruit trees. Leaves can be curled by attacks and may fall prematurely.
The sticky honeydew excreted by the insects can attract sooty mould.
Where you are likely to find it
On the leaves, stems and other parts of plants, particularly on younger areas.
Different species of psyllids are attracted to different plants. Potential victims can include apple trees, pear trees, bay laurel (Laurus nobilis), box (Buxus), alders, eucalypts, apricot, pistachios, potatoes, olives, acacias, persimmons (Diospyros), rose apple (Eugenia), Leucaena, Pittosporum, Siderosylon, willows (Salix) and Tabebuia.
How to deter it
Clear any litter from under plants to remove any overwintering eggs or adults.
Hanging yellow sticky traps around susceptible plants can help to identify a rise in psyllid numbers. Alternatively, place a white sheet or paper under a plant you suspect to be infested, give it a good shake, and see what falls out!
How to get rid of it
Generally psyllid infestations are not severe enough to require treatment. If you do get a bad infestation, prune to remove buds or shoot tips which are infested with the insects. Chemical controls may then be used to clear any remaining psyllids, such as deltamethrin, pyrethrum, fatty acids, plant oils, synthetic pyrethroid compounds (such as bifenthrin), acetamiprid, imidacloprid and thiacloprid.
Gardening with wildlife in mind can attract more natural psyllid predators to your garden, such as ladybirds and lacewings.
Is it good for anything?!
Some psyllids have been used as biological controls, for example in New Zealand to control broom (Cytisus scoparius) which had become invasive.
Other useful information
Fossils of psyllids have been found dating back more than 270 million years, which means that they pre-date the evolution of angiosperm plants (plants that flower).
