dawg:

I would take out trees that are covered with bacterial cankers. I guess you could call that really hard pruning. Sweet cherry trees in fairly advanced stages of this disease have no real future as fruit producers, and will spread the disease to your new plantings of cherries. For the tree that has BC only on the top growth, I would remove all of that now, and hope it does not spread to lower areas. You will know by next spring.

Bordeaux mixture would have no effect on this disease once it is established, nor would any other fungicide I know of. The only way I believe the onset of this disease can be delayed is by several strong dormant sprays with a copper product during the dormant season. But if there are infected wild cherry trees in your vicinity, which are the most common vectors for spreading bacterial canker, it is only a matter of time before the disease returns and begins to affect the trees again. For some reason, sweet cherry trees seem to acquire BC much more easily than sour cherries, even when they are on the same or similar rootstocks.

Bordeaux mixture is also ineffective at treating peach leaf curl once it is established. Once again, the recipe is copper sprays during the dormant season, and that is not a sure thing if a cool, damp spring favors development of the disease.

Don Yellman, Great Falls, VA

"For some reason, sweet cherry trees seem to acquire BC much more easily than sour cherries, even when they are on the same or similar rootstocks."

True, but some sweets do better than other sweets. If you have to start over try 'early burlat'. I think I got mine from Tsagawa nursery in Woodland WA about 10 years ago and I've never sprayed it once. I still have the tag and wished the type of rootstock had been marked but so far it's doing as well as two other sour cherries and I do lots of looking around. There are a few other observations with cherries at WSU Mt. Vernon WA, but there is no substitute to driving up there and seeing them yourself.
(ignore my hobby garden in Alaska-zone 1, I more than one place being attended and have a NW backyard myself)

alcan:

Is seems perfectly reasonable to me that some sweet cherry varieties would be more sensitive to bacterial canker than others. The same is true of apples and cedar apple rust and powdery mildew. There are many other examples.

Of course, there is no way any one person can have personal experience with all the sweet cherry varieties, so anecdotal experiences such as yours can be valuable. At the same time, the sweet cherry varieties selected for a particular location would also have to be well-adapted in other respects as well, such as resistance to cracking.

Don Yellman, Great Falls, VA

thank you all for your advice . i took out all 3 infected trees chipped and burned ALL the wood in my fire pit .