Eucalyptus "fireblight"

[cpp gardener]

We have some very large Eucalyptus globulus on our campus that are displaying similar symptoms to fireblight - 'scorched-looking' leaves that don't fall off and shriveled stems that wilt and dry quickly. On our trees it seems to be especially virulent in that from first signs to entire tree death takes 6 months or less. When you see a 60'+ tree with a DBH of 70"+ die that fast it's pretty scary. We're removing one within the next week or so and I'll try to get a good look at the stump and wood just under the bark to see if there is anything else that might be diagnostic.

 

[Sheal]

It is possible for you to post pictures please. A close up or two would be helpful also.

 

[cpp gardener]

Well, if I must. The first 4 are the dead one and the others are of one about 25-30’ away that is healthy. Hope this helps.

 

[Sheal]

The leaves on the tree in the last image have pest/insect damage. Are all the leaves on the tree the same? Are the leaves on the dying tree the same too. At the moment I would suggest it's a pest invasion not blight.

 

[cpp gardener]

Yes, it's Tortoise Beetle damage. It's not something that kills them unless they're already in severe decline.

I was hoping that one of our Aussie friends might have some ideas.

 

[Sheal]

It's difficult to tell from images whether it's blight or not but I found this New Zealand link that may help you diagnose it. It would seem that the Tortoise Beetle is usually in evidence with blight. The link doesn't state whether it causes the death of trees.

NZ Farm Forestry - Septoria leaf blight of Eucalyptus (nzffa.org.nz)

I was hoping that one of our Aussie friends might have some ideas.

Yes, an Australian member may be of more help. We have Eucalyptus here in Britain but no great numbers of them and I've not heard of blight being a problem here.

Edit: I've just had a thought..... @Tetters would you know anything about this please?

 

[Tetters]

All I know is that fireblight is and has been a big problem in Australia (all my kids live there) It`s a nasty bacterial disease that is notifiable, and can spread rapidly and cause devastation in such as pear and apple trees - also roses. There is no cure, although it can be stopped if found early enough and pruned out and burnt. It is spread by weather conditions such as wind and rain, insects and pruning tools that are not sterilised and can shoot through the gum trees.
I believe it shows oozing sap of cankers - I found a picture

The one good thing is that it does not remain in the soil and I believe you can replant clean plants in the site after removal of dead trees.