Eucalyptus trees

Question

I found bugs eating the leaves of my eucalyptus tree. My tree has lost almost all its leaves. We had a bad flood in October and after that the leaves started turning brown and then fell off.

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Answer 1

This appears to be the 'pup' stage of the Steel Blue Sawfly.
They are know to de-foliate an entire tree.

Here is a link that has more information and management.

https://www.gardeningknowhow.com/plant-problems/pests/insects/sawfly-insect-control.htm