Jumping plant lice nymphs hiding among the tiny hairs on a gum leaf. The largest nymph has a rather large drop of honeydew ready for collection. Kyogle, NSW.
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.