Tropicals & Tender Perennials: A Friend's Hybrid, 0 by RA49

RA49 wrote:
This plant had an awful leaf problem last year ( good eyes Kell). This was before I was part of this site and with Liz's and Jeanne's help, we struggled to identify the problem and fix it.
The owner could never see any insects on it ( and she is quite knowledgeable) but we treated it twice with a systemic insecticide and once with a systemic fungicide. As you can see in the pictures taken in her GH in the late summer, the plant was on the mend and we are hoping it recovered sufficiently to make it through the winter dormancy she put it into. She was unsuccessful getting cuttings to take as they were all too soft and green so we are keeping our fingers crossed.
[She lives in Canadian Zone 2 so dormancy was her only option for over wintering this beauty as it would have been too costly for her to run her GH all year].
I am putting up a pic of the leaves at their worst.... any further input on the problem we would be grateful for, in case she runs into it again this year so we can nip it in the bud.
[The missing parts of the leaves are where the damage was the worst and seemed to 'melt off' rather than be eaten off by an insect.]
[We also gave it some Chealate of iron once it seemed to be recovering].
Thank you.