Unfortunately, it’s in a Belgian fence, so it would be very difficult to make out what’s going on if I took a picture of the whole tree. (I tried, and you can’t really tell what belongs to what.)
Here are some better close-ups, though:
This is the tree that was more affected, which I believe is American Beauty (though I haven’t yet had fruit from it to confirm).
Other observations:
Several twigs had a “burned” look to them - dark discoloration.
Several blossom clusters appear to have been affected. (On the other, less damaged tree, it appeared to be mostly flower buds that were damaged, which seems like it might be blight?)
I cut off several of the damaged twigs. A couple of them had a ring of brown stuff inside. Where I could, I cut back to where I wasn’t seeing brown anymore. But most looked good and green.
I did not observe any damage to the lower trunk. (No sign of borers, etc.)
No sign that the tree had been girdled. Could be root damage, I suppose, but again it looked good and green except for those few damaged twigs.
The damage appears to have affected almost all of the new growth on the tree. It appears to have developed fairly fast. I’ve been walking by the tree several times a day and only noticed it this afternoon.
Yeah, as I was reading what I wrote, I was starting to think that myself. Which stinks, but it happens.
Any sense in
A. Cutting back below the visibly affected areas and seeing if it’s able to put out new growth or
B. Cutting back a lot and trying to regraft either just above the Y or lower on the trunk?
I think the goal would be to keep it alive long enough to graft it over to something else, whether now or next spring.
The harder decision is going to be what I do with the other tree, which doesn’t seem to be hit quite as hard. Unfortunately, it happens to be Roxbury Russet, which is one of my wife’s favorite varieties out of the ones we’re growing (though the apples weren’t from our own trees, because they’re mostly not bearing yet).
I guess the good news is that nothing else seems to be affected.
Usually on most trees the main trunks have latent buds that are not usually visible, but you can most probably save the trunk forcing any latent buds to grow out which should be graftable after a years growth. It’s worth trying by just cutting back until you think you removed all Fireblight. Make sure you burn the material removed. Maybe consult your local County Ag extension agent to see if they are aware of varieties more resistant for your area.
Dennis
Kent, wa
I appreciate that suggestion, Dennis. At this point I’ve cut out all or almost all the visibly affected growth. I’ll check tomorrow to see if I missed anything, and then kind of think on it for a minute. After looking around a bit, and also looking at the trees more closely, I think there’s a chance that it’s blossom blast and not fireblight, and there’s a chance that it hangs in there enough for me to put off grafting until next year, when I’ll be able to do the grafting earlier and give it a better chance to take. (And also have more choices as to what to graft it over to.) That’s what I’m thinking at the moment at least.
Usually a planned approach is more successful than a rushed one, apples are easily summer grafted with green scions, so you could use green scions with mature growth buds around mid to late August from your mentioned favorite variety or even several varieties. So good luck, you have many options left.
Dennis
Kent, wa
Thank you for the insight, everybody. I really appreciate it.
@hambone: The harder hit variety is American Beauty, the other one that got hit but not so hard is Roxbury Russet. You make a really good point about picking varieties that are a good fit for your specific area. As it happens, though, these are both varieties that originated in Massachusetts, which is where I am, so they should be a good fit for the region, although I realize that some diseases and fireblight in particular can be very location and condition specific.
One weird thing: I’ve seen Roxbury Russet rated as very resistant to FB (for example here and here, although Burford rates it as moderately susceptible, as does Cummins). I have another tree of Roxbury Russet right next to the one that got hit that seems fine. There’s not a lot of info out there about American Beauty, but Burford describes it as being moderately resistant to the major diseases.
Another weird thing is that I had very similar damage on my Korean Giant last year, and that is supposed to have good FB resistance for an Asian pear. (I realize that “for an Asian pear” may be the operative phrase there.)
Years ago I lost Roxbury Russet to fire blight here in Md.
Sometimes when there is a split opinion on “blight resistance” it means the variety does not resist getting blight but it does wall it off and resist it spreading and killing the tree. Like King David.
Sorry to hear that. I know that fire blight has been a really challenge in your neck of the woods.
Taking a closer look, I think that the Roxbury Russet is going to be ok. It looks like a few new spurs got burned out, and all the blossoms look like they got toasted, but the leaves look healthy. (And I have another tree of RR a couple spots down in the row, and that looks ok, though looks like the blossoms took a hit there, too.) KG looks ok this year as well.
I just found a stick of Margil in the fridge that I overlooked when I was grafting, and I was starting to think that I might try grafting the American Beauty over to that. But I see that Margil is supposed to be quite susceptible to FB, so that doesn’t seem like the best bet.
@mamuang Thanks for the link. I was looking at this article which says that Pseudomonas can occasionally cause blossom blast on apples (as does this article), which suggests that this is something that’s been seen more often in recent years. This post suggests that it’s been seen closer to where we are in New England. What I’m seeing on the RR actually does seem pretty consistent with the descriptions of blossom blast, and we had a cold snap when RR was blooming, so that seems like it might make sense. But I could be totally wrong!
Question for those of you who have more experience with this stuff: If the American Beauty does have serious fire blight, should I expect to see visible damage when I cut off a twig/small branch? I saw visibly damaged dead tissue in a few twigs, mostly lower in the tree, but otherwise the cross-section appears normal.
Also, on closer examination, I did find a couple of apparent lesions on the scaffold. Does this look like FB or something else?
Thanks again for the info and advice - this is pretty much my first time seeing this stuff, and you’ve really helped me get a better sense of what I’m looking at, what I should be looking for, and what I should do about it.
American Beauty is highly susceptible to fireblight according to this source.
Roxbury Russet’s disease rating varies wildly based on the source. There doesn’t seem to be a general consensus on it. Based on my tree I would guess it to be mildly susceptible to major apple diseases or mildly resistant. I think small changes in disease pressure will easily alter your opinion of the disease resistance of Roxbury Russet and that is why the disease ratings vary so widely.
What rootstock do you have your trees on? If you want to keep it long term you may try a different rootstock. Also fertilize less, slower growth helps with fireblight. Lastly if you have room you might try a higher vigor rootstock. @alan has reported that big trees on rootstocks like M111 don’t have much trouble with fireblight once the tree is established… they can live thru the damage.
Thanks for the link, that’s very helpful! Not a lot of info about American Beauty out there. Sounds like that one is coming out, one way or another, it’s just a matter of what I have to do to replace it.
Almost all of my trees are on G41, including the two that we’re talking about. So hopefully the rootstock under the AB will be resistant and thus more likely to be viable for regrafting. The trees are in a Belgian fence, so a less vigorous rootstock made sense overall, though there are a few varieties where it would have been good to have a little more vigor in retrospect. (Looking at you, Court Pendu Plat.)
We have a pretty small yard, so going the big tree route wasn’t really something I considered, but it’s a good point to put out there for people who may have more space to work with.
I don’t fertilize or water the trees at all; I do mulch, but not super heavily. It’s been a pretty wet spring for us, and a lot of things seem to be growing vigorously, probably contributing to the problem.
You might try Bud 9 if you want to keep American Beauty. Geneva rootstocks are resistant to fireblight but don’t alter the resistance of the scion. Bud 9 appears to actually alter the resistance of the scion and increase it. How it works is unclear.
Here is a thread discussing fireblight resistance in rootstocks.
My first apple tree is a Honey Crisp. It is 15 years old on an unknown rootstock but my bet is on M111. I may have grafted 20+ varieties on it at one point. Only Arkansas Black got fire blight (after 4 years on the tree). Luckily, the blight stopped at the graft union. No damage beyond that.
The only apple variety I avoid was Tydemans Late Orange because the person who gave me scionwood sid it was fire blight prone.
I have a Fuji on G41. I like this rootstock. Again my Fuji is very late (the nursery sent me a wrong tree). I converted it by grafting 15 + varieties on it. So far, no fire blight but you never know.
Bud 9, at least the 5 rootstocks I have, have weak growth and the tree structure (branching out) is not balanced. They definitely need staking. I would not do apple on Bud 9 ever again.
Thanks again for the info! That’s a good thread, and looking into the Bud 9 stuff is pretty interesting. According to this site,
“Resulted from a cross of M.8 x ‘Red Standard’ (Krasnij Standard) from Russia. B.9 has been tested widely and is used commercially in the U.S. In general, B.9 is slightly more dwarfing than M.9 and has slightly higher yield efficiency than M.9. B.9 was selected as a dwarfing cold hardy rootstock and initial inoculation results indicated that it was as susceptible to fire blight as M.9. However, in field trials, trees grafted onto B.9 survived fire blight outbreaks better than trees on other dwarfing rootstocks. Recent reports from research conducted at the New York State Agricultural Experiments Station at Geneva, N.Y. indicate that B.9 becomes more resistant to fire blight as the tissue ages. There are two strains of B.9; the European strain has a more trailing growth habit whereas the North American strain has a more erect growth habit and these strains were compared in the 2002 NC-140 rootstock trial with ‘Gala’ as the scion cultivar. The American strain was slightly less dwarfing and produced more burr knots than the European strain and yield efficiency was similar.” (Emphasis mine)
The two strains part seems to partly speak to Mamuang’s point.
At this point, though, I think I’m ready to let the American Beauty go - it’s too bad, but if it’s proving to be blight prone then I’m prepared to cut my losses. (So to speak.) So plan A will be to graft something else onto the G41 that’s already in the ground, because replacing a rootstock in an established Belgian fence would be a little tricky.
The question is when the best time to do that would be and how far I should cut back to do the grafting. For the first question, I guess the options would be now, later in the summer as Dennis suggested, or next spring. (Assuming the tree survives long enough to give me options.) For the second question, it’s whether I cut back below the original graft (which would be safer) or graft above the Y of the Belgian fence (which would fill in faster, but at the risk of leaving blight-susceptible wood).
What about scions. I generally don’t have any fireblight on a tree that has no grafts. Could grafting introduce it? Is there a recommendation for treating scions once they are received? Most treatments like weak bleach soaking seem limited to those sending scions.
