If you notice that eucalypt trees are taking on a scorched appearance at this time of year it may be due to the caterpillar stage of the Cup Moth, (Doratifera spp.). Last year thousands of hectares seemed to be affected. They are active from spring to autumn.
Dereel is one area recently where landholders have noticed the trees going brown as the caterpillars feed on the leaves. Many eucalypt species are food for the larva but the trees usually recover.
You may have noticed the cocoons but not known what made them. They are a small, rounded and cup-shaped with a tapered top and attached to twigs. Try not to touch the caterpillars as there are stinging hairs which will cause irritation. http://www.dpi.vic.gov.au/forestry/pests-diseases-weeds/pests/cup-moth-alert