Budrot?

[Train Wreck]

Due to the damage that the caterpillars are doing, spraying may be the only option.

 

I don't know anything about confidor but if I was forced to spray this late in your grow, I would use dipel.

 

At least it is a bacterial solution to problem and should have no effect on the canna's tase

[max_headroom]

Oh shit and I thought by baby had issues...that sucks the big one. I have to say I am somewhat amazed at the small level of damage I have in comparison to yours. Mine was caterpillar driven but I found it before it got to the rotten stage apart from a couple of branches that had some minor damage. Sio I have been very lucky to spot it early. Good luck with the recovery

 

Max