I agree on the thought that mixed types on DV seems to be the culprit:
In 2003 I started converting most of my Chocolate branches with hybrids of both Dv and kaki scions. My tree was from Willis orchards and was about 4 years old. Willis said it was DV rootstock. It had fruited several years so I wanted to use it as a pollinator. On 5/20/2003 I Grafted on Chocolate: 1 ea Rosseyanka, David’s Candy: 1 ea, Nakitas Gift: 1 ea, Kasandra: 2 ea, Zima Kurhma, 1 ea
Failures: Great Wall 2 ea, Jin YongTam Gam: 1 ea, ZimaKhurma/Early Golden: 1 ea, Rosseyanka: 1 ea
Many of them budded out and started to look vigorously until I noticed one had black veins and was withered. Within about 2 weeks all had withered! I cut the entire tree down and burned it immediately. Pretty sure it was SDS.
I have other multiple variety trees that are doing fine
After having a very low success rate with persimmon grafts (2 of 12, one of which died over the winter) last year, I practiced my grafting technique in preparation for this spring. Then I attempted to graft 12 persimmon scions this spring using a hot callus pipe. My success rate was 1/12. It was very disappointing. And it was hard to figure out what went wrong. But it was suggested to me that the dv rootstock could have KSDS. A year and a half ago I had, just to see if they’d grow, planted a bunch of seeds from Kassandra fruit that was pollinated by Coffeecake or Chocolate. They were around 3 feet tall. Three of the scions were still alive even though their grafts had failed. Plus I had a few extra scions. So I tried grafting 6 scions to 6 Kassandra seedlings. Well, 2+ weeks later, 3 of 6 of the grafts on the Kassandra seedling have buds starting to open. So it seems like my dv rootstock is mostly infected. Do my Kassandra seedlings have the potential to also be infected? If the mother Kassandra tree and the males are grafted on dv rootstock and growing ok, does that mean the seeds produced would be clean?
The female-flowering “mother” tree (Kassandra) is healthy. The male-flowering PVNA “father” trees (Chocolate, Coffee Cake) are healthy. I can’t see any way that seeds produced by pairing these trees can be infected.
Actually, I’m skeptical that pollen from even an unhealthy tree could carry the pathogen. I’d guess that there’d have to be contact with the sap of an infected tree, e.g., in a graft, insect bite, pruning cut. But if so, then the scions from your failed grafts could be infected as a result of contact with the infected DV trees and could therefore now infect the seedlings.
Question: You have 3 scions from failed grafts, three from storage. How did these split among the 3 that are growing.
2 of the 3 scions from failed grafts and one scion from storage are now budding on Kassandra rootstock.
One of those started budding 4 days after it was grafted. So that seems like it was just used energy from the scion.
If the rootstock is infected, probably these scions are infected too. But if so, I find it hard to believe that those scions would break bud so quickly.
This leads me to wonder if the rootstock trees had some other defect.
In either case, if your success persists then starting your own seedlings will seem the way to go.
Is it known how this pathogen moves through the tree? If it follows sap flow, would there have to be some callusing to make that connection between rootstock and scion? There was pretty much zero callous on the failed grafts and I cut off any part of the scion that had been touching the rootstock so that I could reuse it. I guess we’ll get some more data points as these new grafts succeed or fail.
And I did plant some more seeds for future use, just in case.
Following up one last time, I was trying the above on my KSDS-infected stocks (five total) and it looks like all are sensitive. The first round they all sprouted and then failed on one very infected stock, and I re-grafted all on three other infected stocks and they sprouted but failed again. I still have Chuchupaka and Kasandra alive grafted on my supposed JT-02 on a KSDS-infected stock but they are stalling now so its not clear if they will make it. Maybe the JT-02 interstem is helping some though, they are at least doing better than the ones directly on KSDS-infected virginiana stocks. It would be really nice if an interstem could make things work.
I have JT-02, grafted in 2021 onto an infected tree. It has done well for 5 years but this year it is looking bad, like it is slowly dying. Meanwhile, JT-02 grafted to a stand-alone DV rootstock also in 2021 seems ok.
My tentative conclusion is that JT-02 is somewhat resistant to KSDS but not immune. It dies, just more gradually.
This sounds like you’re on the right track, viruses only show up after cell death starts, so what caused the cells to start dying?
I’ve got a post going questioning if KSDS as they’re calling it is actually due to the self pruning mechanism of American Persimmon, I can’t think of any reason it isn’t likely, and all my questions have been answered in ways which support that theory so far.
This absolutely does not fit the widespread theory of viruses, they’re so tiny, anything can transport them, the nematodes under the soil, insects and wind above. It’s been 3 years and it still didn’t “infect” the tree next to it. This is almost solid proof that it’s not an infectious disease, 3 years and both the canopies and roots were contacting each other.
I’m certainly leaning towards genetic incompatibility leading to rejection, self-pruning, and that’s why they die so suddenly.
I was just wondering about this too, and I think this is the #1 question we can answer! The breeding program for the hybrid Persimmons was started because they wanted to be able to plant Persimmons farther north in Russia and they used the most cold hardy northern Persimmons they could find (Meader is currently being used in new Russian crosses but I don’t think they had it before), if this is a self-pruning issue, we would expect more of it with larger genetic differences, and if the Northern Persimmon is better that would make complete sense. This is an interesting theory and I’ll check to see if there is any information about this problem in Russia, it’s very unlikely they have 60 chromosome DV rootstock there, mostly lotus, but for the more cold hardy ones Northern American Persimmon.
Is anyone else able to confirm that northern DV works or that southern does or doesn’t?
So one can’t be sure even after 5 years (or 3 years for the Saijo mentioned in another thread) if a tree is in the clear. Wow. Hybrid rootstock might be the answer. Has anyone grafted to hybrid rootstock and had that tree survive for more than, say, 5 years?
My thoughts, as a total amateur: Yes, viruses are tiny. In theory, anything might transport them. But in fact, transmission tends to be specialized. Poliomyelitis is transmitted mainly via feces or maybe saliva – shitting and spitting it; measles is transmitted mainly by breathing it; HIV is transmitted mainly in blood and semen.
The pathogen (virus?) that causes KSDS may be concentrated in the circulatory system of the tree (e.g., cambium contact). Contact among leaves, roots, bark may not matter.
A quick autopsy of a victim, hybrid on a 60 chromosome native American, showed a large amount of the cambium black, where as the rootstock appeared normal in color,
I’m assuming that KSDS is caused by a small pathogen (e.g., virus) that is normally spread among DV trees by sucking insects that are not native to the north. [I say this because all of my cases of KSDS come from (1) a single infected DV tree purchased from Stark (though it might have been infected later), (2) DV seedling root stocks ether (a) harvested as root suckers from this infected tree, or (b) purchased in the south. Meanwhile I have a half dozen purchased Kakis, 3 grafted Kakis, 1 purchased hybrid, and 4 grafted hybrids that all seem to be doing OK – despite the fact that they have grown within yards of infected trees. Proximity is not enough. Here, evidently there are no guilty insects. What appears to matter here is tissue contact.]
If all that is right, then the grower in the south may be screwed no matter what he/she does. Infected rootstock is infected; uninfected rootstock is destined to be infected by insects. Sadly, the grower in the north who uses DV seedling rootstock grown in the south is playing Russian Roulette.
But the northern grower who uses seedling rootstock grown in the north may be OK. It probably doesn’t matter whether the seeds are DV or Hybrid. So long as they are grown entirely in the north, they should avoid the insects that transmit the disease. Hypothetically.
So you need your own seeds, which might come from a local DV or hybrid tree – if you’ve got the right male flowers. And then scions from a healthy tree.
Actually I would say I spoke too soon about the self pruning, it does look like it’s a bacterial infection of the cambium, and being such a thin layer, or thin double layer, it’s easy to see why it’s killed so fast after the first symptoms.
This should make me double down on my self-pruning delayed incompatibility due to genetic differences theory, but I do think it’s been pretty well shown to be a bacterial infection of the cambium, perhaps 60 chromosome DV is less resistant to the bacteria, or allows itself to be infected through it’s roots more easily.
But we need more testimonials, did any die of KSDS on 90 chromosome DV?
I’m in Ky. and assume seedlings from my native Americans are 60 chromosome.
When I save seeds from Cliff Englands Americans , I assume the resulting rootstock is 90 chromosome.
Seeds saved from hybrids , I guess are 90 Chromosome.
During the last 4 years I’ve grafted around 40 persimmon seedlings to various seedlings from the above, but the majority have been my 60.
4 have perished from KSDS. All 4 were on my 60 chromosome rootstock. All 4 were starting their second year. All four were hybrids.
