My cotoneaster collection progression

[MMJNICE]

So I've been growing cotoneaster for some years but to be honest Ive killed and sold more then I own right now but mostly just killed do to some kinda fungal infection on the leaves that tend to show up right as the spring time gets really going. It's like this black stuff that I can't fully identify slowly in a matter of weeks to sometimes days just takes them out and they wither away and die. I've had some seriously nice mature trees not make it past two seasons with me but this season was different. I decided to over winter my cranberry cotoneaster in the garage instead of the greenhouse and they got sprayed every three days with a copper fungicide mixed with mancozeb as soon as buds started moving and that has seemed to nip things in the "bud" hehehe.. luckily I put a few cranberry cotoneaster in the ground 3 years ago when they first showed signs of the disease and that saved them from their fate. In the ground they thickened up a lot and got good and strong so im feeling myself and decided that I may have found the trick to keep them alive long-term........ I really hope. So will continue to update this post periodically. I can't sleep because I lost my dog yesterday after 12 years of being best friends and I miss him a lot so bonsai therapy to the rescue.. first two trees are cranberry cotoneaster and the other two are the smaller leaf cotoneaster that keeps some of their leaves over the winter time. The cranberry had been in the ground for 3 years and the smaller leaf ones are much more resistant to disease so I've never lost one of those little guys before. The smaller leaf were grown from cuttings i took a couple of years ago.. All my cotoneaster have all grown a bunch so far this year I know the pictures are a little out of order but hopefully you can tell which picture goes with what tree... These trees are far from being refined trees right now but i see the potential in them for the future. The first tree still haven't picked a front both Sides look good to me..

 

[Notsureaboutplantnames]

Fire blight?
Very fast moving bacterial disease of many plants in the rose family. The leaves die very quickly (remaining attached) and the infection will overwinter on the stems awaiting spring rains and splashing water or bees ti spread.
If you see black areas on plants that have had the rapid dieback that might be where the bacteria overwinter.

 

[MMJNICE]

Fire blight?
Very fast moving bacterial disease of many plants in the rose family. The leaves die very quickly (remaining attached) and the infection will overwinter on the stems awaiting spring rains and splashing water or bees ti spread.
If you see black areas on plants that have had the rapid dieback that might be where the bacteria overwinter.

Fire blight was one of the possibility for the infection the trees have been suffering from. There was a couple of other diseases that I thought could be at play as well but I can't recall what they were right at the moment. I've read a few other posts about cotoneaster that people have been having the same issue and there trees don't make it very long either. Some people have basically given up on cotoneaster and I was almost one of them until this one successful growing season. I'm hoping that keeping the trees separated from overly wet and humid conditions during spring time and the fungal spray will keep them healthy.