I’m hoping that’s what it is, but it does bear a strong resemblance to some of the symptoms on the Corvalis trees, some of which (especially on scaffold branches) seemed fairly minor. (See “fig. 1” here.) I’m going to continue to watch them closely and hope for the best. I fertilize well in the spring, so maybe—if this really is a problem—that’ll prevent it from worsening.
The one with the split trunk has these symptoms all around the circumference of the bole; these are some of the worst. And I was mistaken: it does have some of this subtler cracking farther up; and I don’t think it’s growth-related in this case, because, again, this tree’s not been growing much. It’s also recently put out a sprout (not pictured) just below the canker zone on the trunk. Perhaps the tree’s attempt to save itself from impending demise? I noticed a lot of sprouting/suckering on @growjimgrow 's tree and wondered the same thing. If this one doesn’t grow much next season, I’ll remove it.
I have done a little exploratory scraping (I guess I’m hesitant about cutting more, though I probably should), and have not yet seen any bluish staining.
I looked at my tree this morning. There were no other signs of cracking in the tree. Just for kicks, I did a scratch test at several spots and under the bark all looked good. There are multiple suckers coming up this year, the ones from the trunk I pulled off but left the ones growing around the tree. This is the first year there have been suckers.
I gave the tree some Nitrogen last night so we will see what happens.
Those first 2 pics just look like normal cracking from rapid growth and trunk expansion. All of my 4 pawpaw trees planted in 2016 have been doing that the past few years. Same with my Prok persimmon, which has been growing like a beast. I’ve talked to other people with the same issue on their pawpaws. Nothing to worry about.
So my most mature pawpaw, which I spoke about above, never came out of dormancy. I cut it down and a bunch of suckers came up. I’ve been letting these suckers grow all summer.
My plan was to graft these in the spring to a named variety, let them grow, and then pull all but the strongest. Can this work? Any issue grafting onto the suckers?
If it were mine I would keep all the sprouts and graft each one to a different named cultivar. This will help pollination.plus let you sample a bunch of primo varieties. Growing them close is not a problem for pawpaw, at least from my reading.
I have two other pawpaws also, neither of which is old enough to bear fruit. I will graft some different kinds in the spring and see what happens. Thanks for the input.
Anyone else have issues with cracking bark and cankers on their young pawpaws? I’m noticing more issues with some of my trees above the grafts. I’m seeing bark slightly splitting and then it expanding and pushing deeper into the tree. I had an Atwood that had 3 locations around the scion that were bad enough that I pruned the bad portion out and regrafted it since I was confident it would die anyway. As I looked at others I saw more at different stages of the splits and cankers. This is not SW injury because most of them have it on the north side.
Atwood portion I pruned out…
Tallahatchie with a split…
Nyomi’s Delicious starting to split…
Mango beyond splitting and getting deeply pitted cankers like the Atwood…
Now my wife has mowed through there a couple of times with the riding mower while I was at work. There’s no direct mower contact, but maybe it’s throwing some debris?
I have never seen a wild rabbit here in my 40+ years so it isn’t that. We have had voles over the years, but it’s weird that all of the damage is higher up above the graft. That Tallahatchie and Nyomi’s is about a foot up.
Does this look like some kind of vascular disease? That KSU link isn’t working for me anymore.
I wanted to add more trees, but I’m getting discouraged. I know Cornell tried pawpaws as well a couple decades ago and that failed because of high mortality.
Maybe the solution is to just go with seedling trees with superior genetics and just avoid the grafts altogether? Or field graft them myself at some point?
I found another link to the vascular decline post. Scroll down a bit.
Cool and moist basically sums up my springs…
Efforts to identify the pathogen(s) associated with the decline symptoms in Oregon have been unsuccessful. Dr. Postman believes that the or- ganism responsible for BSD is Psuedamonas blight but no positive identification has been made. He suggests not to remove lower branch- es and is caused by cool and wet conditions.
All of my pawpaws have it to some extent. All are mature to nearly mature trees. And consistent with your experience, almost all of the cracking is on the north sides of the trees. I originally thought it was a pathogen myself (see my posts above in this thread), but now believe it is freeze damage. The cracking was noticeably worsened by our late spring freeze events in 2020 and 2021. But it has not killed my trees—which are heavy with pawpaws this year; nor have I seen any signs of wilt. It could be that pawpaws grown outside of their native understory environment are more susceptible to the vagaries of weather. Of course, freeze damage to bark could open a tree, especially a young and unestablished or otherwise weakened one, to an opportunistic pathogen.
Blue stain is evident underneath some of the cracking, but this is not necessarily pathogenic, as such discoloration seems associated with wound response in pawpaw.
These cracks are widespread on the trunk and scaffolds of the north-facing portions of this NC-1:
Not saying this is the same issue you’re seeing, but the location on northern exposures seems suggestive.
If it’s the same problem I’ve got, maybe not. I see it on seedlings, too.
Also, I know you’ve not seen any rabbits, but your first picture does look remarkably like rodent browsing. It more strongly resembles a cut or bite than a canker.
Thanks for this. I know it looks like animal damage (and maybe that Atwood is vole related), but I have seen some of these progress from small slits and then expand larger. Your NC-1 is a much larger tree than mine as well. Maybe some bark fissuring with a maturing tree? Mine are all about 3/8" diameter or less where the wounds are occurring. I will say the Nyomi and Tallahatchie look healthy based on the new growth.
There isn’t much I can do on the north side of the trees. Maybe some kind of wound sealer could help save the trees I have now? Has anyone tried that IV Organic 3-in-1 plant guard?
I didn’t notice any of these splits after the spring thaw. But April and May can feature a lot of moist, cool days with rain/drizzle/fog and 40s for temps. I really don’t want to hack my trees all up and give up on them too early so I’ll take your lead and just stick with them unless the cankering gets too bad. At least I got some pics so I can compare and see where I’m at in a few weeks. Maybe actually I need to make an effort to keep my trees more dry?
I definitely wouldn’t give up. Are any of the trees suffering much in terms of growth and overall health? Except for those bite-like cankers, they really don’t look all that bad to me. I suspect that paint or whitewash—or maybe a tree tube with a young tree—to protect the trunks wouldn’t hurt.
Perhaps our resident pawpaw experts—and I am certainly not one of them —will chime in.
I’ve had some mortality every winter…a couple here, a couple there. This year 2 trees didn’t wake up and a third tried to leaf out and then just stalled and failed. A cut it up a bit and found brown cambium above the graft, but then a portion of the rootstock and upper third of the scion that was green. So I tried an emergency regraft on that as well. That was a little over a week ago so we’ll see if it takes. Probably not at this point in the season, but it was probably going to die anyway.
It seems like when these trees wake up they’re ready for the heat, and my region can’t consistently provide that until June.
—will chime in.