Psylla is a genus found in the insect family Psyllidae. Insects in the Psyllidae family are sometimes called jumping plant lice due to their small size, shape, and ability to hop off plants when disturbed. Like most of Psyllidae, insects in the Psylla genus are sap-suckers. This way of feeding makes them prone to transmitting tiny pathogens from plant to plant, but not all of them will do this! There is a total of 110 species in the genus. Unfortunately, a fraction of species will use garden plants as their host.
A good food resource for other predatory insects, like lady bird larvae!
Some species can cause leaf mottling and attract black sooty mould.
Adults: The adults are generally pale green, the wings transparent. The wings are attached on the lateral areas of the body, coming together to form a roof over the abdomina region. The antennae are around 2x the length of the head region. Nymphs: The nymphs are similar to the adults; however, they're typically smaller in size, a paler green, with no wings. They look very lice-like at this stage. Eggs: Generally yellow-green, stuck beneath the leaves of plants in clusters. They are tiny!
There may be a white waxy deposit over the plants younger leaves. This is a byproduct of sucker activity. New growth may be stunted the following spring. Cupped leaves that are found near the shoot tips can become similar to that of cabbages. Green, lice-like insects may be found beneath the leaves of plants. Sticky, clear liquid on the leaves of plants. This is followed by the growth of black, sooty mould on foliage. Pimple-like growths on leaves.
Most damage caused by this insect is aesthetic. If plants are well established, it's not necessary to apply any form of treatment. It's advised to prune the damaged parts of plants regularly. Do random checks on leaves to look for eggs, wipe away with some rubbing alcohol or homemade insecticide. Gently spraying plants down with a hose to remove any eggs and insects will make any biocontrol more effective. You can attract beneficial insect to the garden by keeping some areas wild while planting a good selection of indigenous flowers.
It's not recommended to use chemical treatments to deter this pest. Sometimes, the plant in question will be too large to cover in pesticide. Their jumping behaviour can make them difficult to treat when on plants, because of most often, they are gone before you can spray them with a contact insecticide. If plants heavily infected, you can apply organic pesticides to gain control of the insect nymphs. Regular reapplication is key to success when using organic products. There are also more persistent chemicals if the above is not suitable. These include the synthetic pyrethroids lambda-cyhalothrin and deltamethrin. Please read and follow the manufacturer's instructions carefully before any products are used. Approach the above with caution. These insects should be controlled by natural enemies alone, and the use of chemicals may remove such insects from your garden, exacerbating the problem in following years.
These insects use a range of plants in Betulaceae, Rosaceae and Buxaceae as the primary food. Please see the list of example genera below!