what sort of disease are common on malley gum trees. Have noticed a white film over the leaves?

Question

we have found a white film over the leaves and they dont look as healthy

Answer 1

Eucalypts can be colonized by psyllids that build little "houses" called lerps (see link). However, these are white crystalline structures that will chip off like scales, not white film. But this is the best I can do right now.