Powdery mildew (possibly Podosphaera sp.) infesting zucchini leaves and stems. The ladybird is a fungus-eating ladybird Illeis galbula about 4-5 mm long.
It seems both Golovinomyces orontii and Podosphaera fusca (for relevant synonymy see Species fungorum) occur on Zucchini and occur in Australia. Examination with a compound microscope would be needed to distinguish between the genera and molecular methods may be necessary to confirm species. Not a group I've ever really looked at, so family level identification of Erysiphaceae is as far as I can take it. Current reference seems to be: Taxonomic Manual of the Erysiphales (Powdery Mildews) by Uwe Braun and Roger TA Cook pub. 2012.