Female psyllid (Cacopsylla picta), coloured scanning electron micrograph (SEM). This specimen has just undergone its final moult. Psyllids, also known as jumping plant lice, are sap-sucking insects that are a major agricultural and garden pest. As species tend to be host specific psyllids can be used as a form of biological control for invasive plant species. Magnification: x17 when printed at 10 centimetres wide.