I am no expert on your problem(s), but since no one has chimed in, I thought I'd relay what Peter Tea instructed me to do last year. I had some scale and fungi issues last spring. He believes in a preventative systemic pesticide (you have wholly aphids) and systemic fungicide. His advice, based on his time studying in Japan, is to treat with 2 specific chemicals every 3 months and he said I will have no problems. So far, I have had no issues and the fungicide targets specific fungi and will not harm beneficial mycorrhizae. It's always dodgy to recommend systemic chemicals and I am sure some are against their use, but I don't like problems, especially ones that when noticed are typically a lot harder to deal with by then.
The products are:
Pesticide- Merit .5 G
Fungicide- Cleary 3336 DG Lite
Both are systemic and applied as small granules. What he said I would encounter, and I did, was that it's only available in rather large quantities, 30 lb bags I think. I believe these are mainly used at golf courses and the like. So, I purchased both chemicals and have been selling 1lb bags to club members locally. Not very much is required, I would need to double check my notes, but it is about a teaspoon per sq/ft. I assume (from the warnings on the bag, which you can google and see the bag and specs) that these are fairly powerful and should be treated as such (wear gloves, avoid breathing, etc) PM me if you want.
Hope that helps.
Patrik
