Can SomeOne Please Identify this Grub (pic included)?

Question

I live in Australia so i dont think its a HuHu grub! It lives in & has been eating the "Trunks" of our Hibiscus shrubs (Not the leaves) & when you break off a branch its like a sawdust substance. Can someone please tell us what type of grub it is, is it much of a hazard & who do we call/what do we do about it? thnx!

http://i329.photobucket.com/albums/l386/XxSpanziiXx/WoodWorm.jpg

p.s. sozz its not very clear!

Answer 1

Here in the States we have a resource through our University Extension services who help us out with stuff like this. Check for these clues. Look really close to the exterior of the tree trunks. Do you notice any holes in them? If you do, cut away a part of the bark near the hole. Look between the bark and the live area of the tree and check for tunnel action. GOOGLE 'Emerald Ash Borer Damage' and you'll see what I'm talking about. See if you have a local government agency like a forestry service, a University horticultural department, etc. They should be able to help you especially if it is an exotic/non-native creature like the EAB has been here for us.