Kaki sudden death syndrome -- help?

[marten]

UPDATE April 24, 2024.

Saijo looks done for. The trunk still has green cambium, but last year’s growth is brown and dead:

My remaining Saijo is about 50 feet away and appears totally unaffected.

Nikita’s Gift appears to be doing a death rattle:

Note the black streaks in NG’s leaves:

The Fuyu is getting worse, also, but not quite as rapidly as Nikita’s Gift:

Not every leaf is affected (yet), but those that are appear to be randomly distributed (not limited to any scaffold) and in severe condition:

@Thazo1979

I wonder if hybrids have better luck surviving sds, because I would love to have a Jt-02

Nikita’s Gift is a hybrid, and if what I am describing here is indeed kaki SDS, it is definitely not immune.

If the problem is somehow related to D.V. rootstock, I wonder if I could try D. kaki rootstock. Lotus is not a good rootstock for the east coast – it seems to want to leaf out too early.

[Thazo1979]

If it is a rootstock incompatibility between a kaki and DV instead of a pathogen which causes the decline, I wonder if anyone has tried a double rootstock graft to see if that helps. By that I mean grafting a lotus into a dv, and ontop of the lotus graft the kaki. Of course I have no idea if a lotus on dv would be less likely of a rejection, and the same with kaki on a lotus.

[Yoda]

I’m wondering if the SDK problem is most closely related to whether 60- or 90-chromosome DV rootstock was used. Has this been looked at? All of my grafts on rootstocks from one northern source have worked well, while a single tree from another source had three of four grafts fail. (The one that worked was a DV.)

[marten]

Not by me.

I am pretty confident that all of my kaki, including the ones dying of SDS/whatever, are on northern (90) D.V. rootstock (except for one that is on lotus), because I ordered them all from online nurseries. Also, I think I remember seeing a residual DWN tag on one or two, and DWN uses northern rootstock.

Edit: To be clear, the tree on lotus is not dying, but it is about 1500 feet away from the stricken trees and is planted close to two other kaki on D.V., neither of which is dying.

[GrapeNut]

The symptoms look consistent with SDS, at least as depicted in this paper.

@Thazo1979

If it is a rootstock incompatibility between a kaki and DV instead of a pathogen which causes the decline

Rootstock-scion incompatibilities are often pathogen related, especially when you have such a rapid decline of the scion. Usually, the rootstock is resistant to the pathogen while the scion is not, and the immune response of the rootstock to the pathogen ends up disrupting the flow of sap through the graft union.
From the paper I linked above, the symptoms appear to stop at the graft union, which is pretty consistent with pathogen-induced graft incompatibility.

@Yoda

I’m wondering if the SDK problem is most closely related to whether 60- or 90-chromosome DV rootstock was used. Has this been looked at?

In kiwi, diploid, tetraploid, and hexaploid rootstock-scion combinations appear to have no effect on compatibility. That seems to be the case for citrus as well. I would be surprised if ploidy had any major effect on graft compatibility for any plant. You could have differences in scion vigor though.

That said, given that all DV rootstock is non-clonal, and the species has a wide distribution, it’s possible that different populations of DV have different susceptibilities to whatever pathogen is causing SDS, whether it’s Xylella or a virus or combination of pathogens.

[ncdabbler]

SDS (Sudden Death Syndrome) Kaki Decline

I have an old male D. virginiana in my yard that puts up a lot of root suckers, but I’ve never had any success grafting kaki scions to those root suckers after trying dozens of times. The grafts always look like they’re taking and then die back after a month or so. I’ve had good success grafting to the root suckers of purchased kakis grafted onto D. virginiana. Some of my purchased kaki trees succumbed to what looked like SDS (sudden wilting on portions of the tree, blackening veins in the le…

[jrd51]

This is pretty depressing. Just to understand my required response – Based on the article linked above, it seems that the bacterium Xylella fastidiosa is responsible for SDS. This bacterium is mainly found in the southeastern U.S. (with some CA and midwest). I assume that the bacterium can be transported elsewhere either in (1) infected rootstock trees; or (2) grafted trees on infected rootstock. If a tree is affected outside the southeast, what are the right steps to eradicate the bacterium locally?

I assume we should burn affected trees. What else?

[kiwinut]

A different strain of the same bacterium causes Pierce’s disease in grapes. It’s limited by winter cold. A cold winter can eliminate it, usually below 10F for several hours. SDS likely has some type of cold limit as well. I haven’t heard of it occurring here in middle TN, but we also don’t see much Pierce’s either. However, Pierce’s is creeping up into southern TN, so I wouldn’t be surprised if SDS is too. Since it’s asymptomatic in D.v., it could easily go unnoticed.

[swincher]

It’s a pretty impressive bacterium in terms of number of species that can host it… from the wiki page:

Host species

X. fastidiosa has a very wide host range; as of 2020, its known host range was 595 plant species, with 343 species confirmed by two different detection methods, in 85 botanical families.[34] Most X. fastidiosa host plants are dicots, but it has also been reported in monocots and ginkgo, a gymnosperm. However, the vast majority of host plants remain asymptomatic, making them reservoirs for infection.[citation needed]

Due to the temperate climates of South America and the southeastern and west coast of the United States, X. fastidiosa can be a limiting factor in fruit crop production, particularly for stone fruits in northern Florida and grapes in California.[25] In South America, X. fastidiosa can cause significant losses in the citrus and coffee industries; a third of today’s citrus crops in Brazil has CVC symptoms.[29]

X. fastidiosa also colonizes the foreguts of insect vectors, which can be any xylem-feeding insects, often sharpshooters in the Cicadellidae subfamily Cicadellinae.[3][21] After an insect acquires X. fastidiosa, it has a short latent period around 2 hours, then the bacterium is transmissible for a period of a few months or as long as the insect is alive.[citation needed] The bacterium multiplies within its vectors, forming a “bacterial carpet” within the foregut of its host. If the host sheds its foregut during molting, the vector is no longer infected, but can reacquire the pathogen. At present, no evidence shows that the bacterium has any detrimental effect on its insect hosts.

It sometimes causes symptoms in avocados, apparently, so that’s something new for me to worry about!

[ncdabbler]

I’m really sorry to see your pictures, and I feel your pain. I’ve lost a dozen or so kakis and hybrids to this, and it always seems to hit around this time of year when the trees have put out an initial flush of leaves and look healthy. It starts at the tips of a few branches and works its way down the tree. Sometimes the trees survive one year only to succumb the next. I’ve had trees that were 4 or 5 years old and produced baskets full of fruit die within a few weeks. The D. virginiana rootstocks survive, but no kaki or hybrid graft that I’ve ever subsequently tried on them will grow beyond a few weeks. The scions will put out some leaves and look like they’re going to make it only to wither. I’m not sure it makes any sense here in the Southeast to destroy the infected rootstocks because we’re surrounded by wild trees that presumably carry the same pathogen. Initially I dug them up and burned them, but a few I’ve since regrafted with named D. virginiana cultivars that have grown well and produced fruit. I was so discouraged the first time I lost one of my older kaki trees, but now I just try to keep planting a couple young kakis every year to replace any that die (on average about 1 or 2 a year). Kakis bear relatively early and are such productive and low maintenance trees, that it’s hard to justify giving up growing them entirely just because a few will die suddently and unpredictably. I now look at them as a perennial fruit crop that needs regular replacing. We probably aren’t going to get the 100+ year old kaki trees here in the Southeast US unless some cultivars are resistant. I’ve lost Saijo, Sung Hui, Giombo, Tam Kam, Hana Gosho, Kasandra, Coffee Cake, Miss Kim and probably a few others. My oldest tree that never got infected was Tecumseh (though I eventually had to cut down that particular tree after 11 years to make room for a new septic drain field). I hope your other kakis survive and you don’t lose so many again in the same season. Growing fruit isn’t for the faint of heart!

[sockworth]

Hi @ncdabbler , would you know if the SDS affects kaki grafted onto D. Lotus rootstock?

@GrapeNut mentioned above “the immune response of the rootstock to the pathogen ends up disrupting the flow of sap through the graft union.”

I wonder if D.Lotus and Kaki have would have such a drastic response to the pathogen as DV+Kaki Combo.

[scottfsmith]

Thanks for this report, @ncdabbler. This sounds very similar to issues I have had. I also tried many times to graft on the stocks and it never worked. Right now I unfortunately have my only two mature trees left in decline; four or so are already gone. I did start putting in completely new trees a few years ago so hopefully those will be going strongly before the older trees give it up completely. I agree that kakis in our kind of climate are less than perennial. Now that I know the routine I will be more quick to replace things.

[ncdabbler]

I haven’t ever grafted onto D. Lotus because I’ve heard it is less suited to our heavy clay soils. Not sure if it’s also susceptible to the pathogen causing KSDS, but I doubt it would help save any D kaki grafted to it

[sockworth]

I’m North of you in VA. I’m growing the D. Lotus trees from DWN and they are about same vigor as m111 in my heavy clay hillside soil. I also have a NG on DV but it’s few years younger in the same soil but I can’t tell a vigor difference between it and the DL+Kaki.

If both DL and Kaki are susceptible to the pathogen causing KSDS, it’s possible there’s a different reaction than DV+Kaki, assuming DV is resistent to the pathogen. Just extrapolating based on what @GrapeNut posted.

To my knowledge, I found no posts about DL+Kaki KSDS and knowing how prolific DWN trees are, it is a good sign.

[evilpaul]

I don’t know if it is the case or not, but it’s definitely possible Lotus rootstock trees wouldn’t have the same problem as DV+Kaki.

[ncdabbler]

Good luck! I interpreted what GrapeNut wrote above to explain why you can’t regraft to a D Virginians rootstock that has survived after the D.kaki scion succumbed to KSDS. I would expect that D lotus rootstock would either die if it isn’t resistant to KSDS or no longer accept a D kaki scion if it is resistant. It would surprise me if the rootstock confers any resistance to the disease in the scion since it always seems to start at the tips of branches and work its way down to the graft union.

[sockworth]

As I understand based on reading this thread and others, the infected DV rootstock would no longer accept Kaki scions because when you graft a Kaki scion to infected DV, the resistent DV rootstock infects the Kaki and DV rootstock rejects the infected symptomatic Kaki scion. It’s suggested in this thread that this resistant rootstock with symptomatic scion combination plus the pathogen causes KSDS to occur.

If both DL and Kaki are symptomatic to the KSDS-causing pathogen, the pathogen could cause health issue for both DL+Kaki, but perhaps the Kaki rootstock would not reject the scion in such a dramatic manner. That is what I hypothesize could be the case, but with zero proof.

[marten]

UPDATE (pictures as of May 5, 2024).

Patient Zero (the Saijo) is toast:

Similarly, Nikita’s Gift appears to be not long for this world, with only a bit of sickly new growth clinging to life:

The Fuyu continues to weaken and shed leaves, but its decline has not been quite so rapid. I wouldn’t place a bet on it, though:

I had a scare with some sort of leaf spot on a few other kaki that made me think that the SDS had spread to them, but the black veins did not appear and an application of fungicide cleared it up. I had previously eschewed spray treatments on my kaki, but now I’m taking no chances with the survivors.

@sockworth

To my knowledge, I found no posts about DL+Kaki KSDS and knowing how prolific DWN trees are, it is a good sign.

I have one kaki on lotus, and it hasn’t been infected so far. However, it is in a different location and none of the kaki around it, which are on virginiana, have been infected either. I am not a fan of lotus because mine appears less vigorous and also prone to leaf out too early relative to my other persimmons, but I would change my tune in a hurry if it turns out the the combo protects against SDS. I’m not very optimistic, though.

@ncdabbler

We probably aren’t going to get the 100+ year old kaki trees here in the Southeast US unless some cultivars are resistant.

Thank you for your thoughtful and informative post – I reread it several times and it allowed me to get through the stages of grief faster. I admit, I’ve been just a little smug when neighbors have expressed surprise about my “huge sweet persimmons” and wondering why they’ve never seen them grown here before, so maybe this is my comeuppance.

I really like old trees – having an orchard of old but still productive trees one day was my goal starting out, and so I think that’s going to bias me toward Americans, or mostly-American hybrids, for the future. I greatly appreciate your list of varieties that succumbed, and it looks like my experience puts the hex on Nikita’s Gift as well. I’m hoping that some of the hybrids with a greater proportion of American genetics, like JT-02, might prove to be immune.

[sockworth]

I appreciate you and others sharing these sad stories and allowing less informed people like me to learn from it.

I have DV+NG, 2x(DL+Kaki), and loads of wild DV within “a stone’s throw” so I will post any finding as well.

[zendog]

Last year I had tried multiple times to regraft a Rosseyanka that had died, thinking it was cicada damage that did it in. That tree rejected multiple attempts to graft kaki, then hybrids, then strangely even American grafts failed, but perhaps those were just too late in the season.

I dug it out and got rid of it, but now I see my Prok that is 15 feet away, with added grafts of American, Kaki and hybrids, is showing ominous signs. I had Gora Roman Kosh on the top, plus one upper side branch and both grew great last year, started out strong this year and in the last 2 weeks have suddenly weakened with the leaves looking almost rumpled and the tips dying back. A Sosnovskaya graft and a Matsumoto Wase graft, both of which are on branches lower down still look fine and the three American varieties all look fine as well. You can see a happy Ruby branch growing in the background of some of these shots of GRK looking bad.

I’m wondering if I should just cut off the GRK now and graft an American in its place. And I’m also wondering if the Sosnovskaya and Matsumoto grafts are doomed or if it is anything like fireblight and if I cut away the bad part maybe the infection doesn’t spread. This is a bit different than other examples here, since the base tree is Prok and these are all different grafts on branches. Ugh.