What's ailing my pear tree?

This is about one of my three Seckel pears. I'm in California. Never had a problem with the pear until this year. It started with one branch getting weird leaves in July, and over the course of maybe two weeks they all turned black. I cut the whole branch off, hoping this would be it. Same thing happened a month later; I cut that branch off. Well, now the tree is loaded with fruit, and two more branches are beginning to decay the same way, with the fruit slowly shrinking. I don't know what to do; first off, I don't know what I'm dealing with and then I feel if I cut every branch that gets sick off, I'll be left with a branch less trunk. If I don't cut them off, they might infect the other trees. It looks somewhat like fire blight, but the timing and way the branches go downhill don't quite seem to match the description. Any ideas? (sorry, the pics aren't that great, but maybe enough to identify? At any rate, the healthy part of the tree is a nice green, whereas the sick ones are "holy" and reddish brown with the veins showing.)

This is how it starts:

Hi Christine, So sorry to hear about troubles with your pear tree. I don't have a great answer for you but I'm sure someone will come along soon who has a lot more knowledge and can probably help you.

In the meantime this might be somewhat helpful..... I added a dozen fruit trees to my food forest in this last year. They are all doing really well except for my 2 cherry trees. Their problem was similar to yours but mine is a bit different, it effected the tips of all the branches, just not quite so drastically.

Since it definitely looked like a disease or a fungus I did what I always do, I went online and looked for a good extension service for the answer. Every state in the country has their own universities which each  have their own extension services for all things agricultural. Some are much better than others. Here in Arizona our extension service doesn't seem to do any independent research, leaves a lot to be desired and is never helpful but lots of them online are terrific.

So I typed in 'diseases of cherry trees' and added .ext or .edu to find the extension services first and then I look at 'Images' to try to find the picture that looks like my tree. Lots of them like Purdue University or the University of Michigan are excellent! There are lots of great ones. That's a good place to start.

When I typed 'diseases of pear trees, branches turning black and dying .ext .edu' these are just a couple of the websites that came up....

https://pnwhandbooks.org/plantdisease/host-disease/pear-pyrus-spp-pseudomonas-blossom-blast-dieback

https://www.purdue.edu/newsroom/releases/2014/Q2/deadly-fire-blight-in-flowering-pear-trees-still-a-problem.html

As for the 'weird stuff on the trunk of the tree'... I think I can answer that question. In all the research I did for my cherry trees I found this same answer dozens of times. When a tree is stressed it will often exude 'GUMMOSIS' from it's trunk. You can look that up too. “gummosis on pear tree. It is a sign that the tree is stressed. According to the experts, trees exude gummosis over practically anything that stresses them, too hot, too cold, bugs, diseases etc.

In the end I could never get a definitive answer for my cherry trees unless I take cuttings and send them to a lab for diagnosis but it looks like they have a bacterial canker, 'Pseudomonas syringae'. My van cherry overcame it and is starting to do much better but my bing cherrry is exuding lots and lots of gummosis and probably won't survive this winter.

Hope this helps and isn't too depressing. And I'm sure someone will come along with a better answer for you. Best of luck.

Thanks, Debbie Ann, for your long and thorough reply! As it happens, I wrote my extension agent just 2-3 hours ago. Hopefully, he/she can shed some light. And thanks for the explanation of Gummosis. Makes sense.

I just looked up your links. I think tree really does have FB and if I can save it at all, I'll have to spray copper a bunch of times. I don't quite think it's blossom blast. Oh well. I'm just hoping the other two trees will not get infected.