What is wrong with my LillyPilly, it has sawdust at the base of it and the leaves are dying
trees 7 years old 3 metres high have just started to die-leaves brown and branches dying? ? borers
From your description, unfortunately it does sound like borer damage. It is the larvae of the longicorn beetle that does the damage. The sawdust that you are seeing is evidence that the larvae is tunnelling underneath the bark in what is called the phloem-cambial region. This area contains the cells in which water and nutrients are moved around the plant. When this is interruped, branches will start to die back and the tree will show signs of being under strees. It is likely the adult beetle has gained entry to the tree at the base either because damage to the trunk has occurred, or too much mulch has built up around the trunk making the bark soft, resulting in easy access for the beetle's entry. To start with, move back any mulch from around the tree. The next step is to keep the tree healthy so it can survive. Water the tree well and apply regular applications of seaweed solution. Prune back any branches that are dying back (which is where the grub will be present) to hopefully initiate some new growth. Once spring arrives, apply a slow release fertiliser to keep those nutrients flowing. We would suggest an excellent fertiliser called Acticote for Natives. With a little TLC, I am hopefully that your lillypilly will survive.
Answered: 4 Aug, 2014