Psyllids suck sap out of a leaf and produce honeydew which is collected by ants. When psyllids are present in large numbers, sooty mould will often take over the leaf and is detrimental to the health of the tree. Kyogle, NSW.
Psyllids (bottom) and the Notoncus ant responsible for honeydew collection. In winter the ants are less active but the jumping plant lice nymphs still produce copious amounts of honeydew. On the left you can see some sooty mould that thrives on psyllid honeydew and is detrimental to the health of the leaf. Kyogle, NSW.
The underside of a gum leaf is host to a variety of life. This image shows two psyllid nymphs (bottom) hiding under an empty ladybird pupa which is next to the yellow eggs of another ladybird. Psyllids can build their own little houses called lerps, but on this tree they are out in the open. Their sheer numbers are protection enough but has resulted in black sooty mould taking over most of the leaves on the tree. Sooty mould loves to grow on the honeydew excreted by jumping plant lice. Kyogle, NSW.
