Hi Geoff,

If you can send a photgraph that may help simplify identification of the problem. It maybe leaf blister sawflies which are small insects that mine the leaves giving a brown blistered look to the leaf. Another option could be leaf spot which is generally more survire on the juvenile leaves of Eucalypts. Often these do not need to be treated. Do you have possums in your area that could be running up the truck causing damage? Yates has a wonderful new product available - Yates Possum Repellent Spray helps protect your precious plants by deterring possums from browsing on sprayed plants.
Features
Contains a special combination of ingredients that help reduce possums browsing on plants.
Lasts for up to 7 days or more with regular re-treatment.
Can be used on ornamental and edible plants and has only a 1 day withholding period.
The formulation was developed by Professor Lynne Selwood and is protected by a patent granted to the University of Melbourne.