What disease is ailing my pear tree?

This is about one of my three my Seckel pears (the other two are healthy). 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.)

Cut everything off?

Cutting won’t help. In southern & central CA climates it arrives in Dec., Jan. and the malady is set. The effects take all year to unfold. Preventative measures (chemical spray) can be taken at Thanksgiving and New Years. Monterey Gardens “Liqui-Cop” is a good choice for home owners without pesticide licenses.

So it’s definitely FB? Is there any hope to even save this tree? Right now it’s gradually dying–would spraying it now do anything, at the very least to prevent it from spreading the spores around? Or do I simply have to wait until Thanksgiving, praying it will survive and not get the others sick?