The gums aren't looking the best, patches of dead looking leaves all over them. These are lerps. Lerps are the protective cover made by the nymphs of the jumping plant lice or psyllids. Adult and nymph psyllids are both sap suckers and heavy infestations of nymphs can cause significant leaf drop and defoliation in trees. These outbreaks occur after a succession of dry conditions.
Nymphs excrete honeydew on the leaf surface. The sugars and amino acids in the honeydew crystallize in the sir to form lerps, as can be seen in the photo.
