Fruiting cherries don't suffer here from black knot. Italian and Stanley plums are pretty resistant. Of Japanese types, I find none especially resistant yet, (besides an unnamed experimental variety I got from Cummins that is no longer available) but Methely is by far the most susceptible and should be avoided in high pressure areas. It is a typhoid-Mary of black knot.

I've grown Roadside and President.

Roadside wasn't very good. President was a decent flavored plum and is bigger than Roadside. Here, President was worth growing, Roadside wasn't.

President does ripen very late.

Ruby Queen is an excellent-tasting Japanese plum bred in Georgia. I don't know how knot resistant it is supposed to be but I have never seen a knot on my tree. In general the modern southern breeding programs are the place to go for black knot resistance; it was not something they bred much for until more recently. The AU series unfortunately seems like they focused too much on disease resistance etc and too little on flavor.

If you are regularly walking through the orchard and are keeping the trees low (for easier patrolling for knots) you should be able to keep any tree healthy. I am cutting out knots all the time and have yet to lose a major scaffold or tree to black knot.

Scott

I have the same [problem with black knot infested wild black cherry rampant in the woods adjoining my property. Lost an ornamental plum and ultimately a Stanley and Green Gage plum to black knot. Just returned and got worse every year despite aggressive pruning. Finally planted Shiro, Santa Rosa, and Fortune Japanese plums which (these three varieties) are suppose to be resistant. So far after 4 years......no black knot. Sweet cherries have never shown any black knot on my property. Good luck. Black knot is devastating.

http://www.caf.wvu.edu/kearneysville/tables/bknotsus.html

Table of Plum Cultivar Susceptibility to the Black Knot Fungus
Apiosporina morbosa

Here is a link that might be useful: Table of Plum Cultivar Susceptibility to the Black Knot Fungus Apiosporina morbosa

I would question any table if I didn't know how they came up with their evaluations (well, it if contradicted my own experience, that is). Maybe it is a question of state, but in the sites I manage Methely is much more susceptible than any of the many plums growing- this includes over 20 different varieties, including Damson.

In my nursery I have Methely growing with other varieties and over the years it is so hard to manage for black knot that I'm not going offer it anymore. You can see all the extra wounds in this variety from cutting, cutting , cutting.

In home orchards there is usually some sun blockage and if this occurs from the east the equation will be much different than on any university testing site.

I have 3 Damsons on a site with good exposure and it doesn't suffer more than other plums there. However, on that site Methely doesn't suffer a whole lot either although a bit more than the Damsons. But then, I've resisted Damson's tendency to be a dense upright growing tree- a form that makes drying difficult.

You cannot know about how easy or hard black knot is to manage unless you have managed it at multiple sites. There is huge variability on the problem that often can't even be explained by sun exposure or nearby native cherries.

I've had a fair amount on Santa Rosa and its labeled resistant there.

I agree that the Damson rating is probably more to do with how thick with shoots it wants to grow. It shows how tricky these ratings are.

Scott

We have wild plums with black knot, so I will have to get the resistant plums.

So I realize this is an old post, but an ongoing problem. So this is my experience. My Methley, Burbank, Bruce, Stanley Prune, Santa Rosa, Shiro, Sweet August Sensation, Hanska, and Black Ice have all succumbed to Blacknot. I have Native Plums in all of the neighbors yards and they have it. There is also native Black Cherry trees everywhere, so genetic resistance is the only thing that will work for me

The trees that have remained unaffected for me are: Superior, Alderman. I have now planted Waneta, Early Italian, Seneca, NY 9 (Kenmore), The President, Oblinaja. I will plant Bluebyrd next year when I find it. Another nursery just told me Au Rosa is resistant and I read that Bubblegum( I think used to be Toka) was listed on another site as being resistant , so I will try it.

My Cherries and Peaches are unaffected by Blacknot.

What are your cherries & peaches vestries?

Montmorency Cherry and Northstar. They never get anything. The Peach is a tough one. It was supposed to be a J H Hale I think, but its an odd one. Its completely yellow skinned, about baseball sized or slightly smaller, and is very , very fuzzy. It has tons of fruit, but I havent been able to identify it. I put in a new BlushingStar Peach last year, and a Reliance this year as well.