Corky Bark Disease on Langsats

[LangsatFL]

I want to ask all of you that grow langsats about what your experience has been with corky bark disease on your lansiums.  Do your trees have this condition?  Have you found any effective way to cure it?  Do you have any idea how to prevent it?  My old Langsat trees all have this condition here in Florida as well as some of my Burmese Grapes (I know they are not related).  I believe that the corky bark causes defoliation and die back on my Langsats.  I have seen it over and over again now.  I’ve had massive die back on some of my large Langsats and I always find corky bark on the base of the branches that die back.  I have tried scraping the corky bark and spraying with copper and with an insecticide but the condition comes right back.  Some of my trees don’t get it as badly as others.  It seems to be really bad on Long Kong.  Not too bad on my Duku.  Any input you have will be greatly appreciated.  There is very little information online about this condition. 

[Gone tropo]

hey mate i think you and i have discussed before about our issues with these trees, and we had similar experience on different side of the world. I have an air layered duku langsat that is 4 years in ground barely grown about 3 ft tall.  I dont know what disease it has it doesnt die it just refuses to grow, It puts out new leaves maybe once or twice a year max the new leaves look great then they eventually get all kinda crinkly looking and go to crap.  I dont know whats wrong with it but something is. I refuse to pull it out as it cost me $100 and it still stays alive I hope one day it might grow

[LangsatFL]

Hi, yes I remember.  The langsat I had that was terribly sick eventually got much healthier once I put up some shade cloth around it and gave it a weekly chelated iron drench for about 3 months or so.  I think the wind that we get here in Florida was greatly weakening it. It was also probably getting way too much sun I think.  I’ve noticed they seem to do better with some sort of shade.  The disease I am talking about now is different though.  This corky bark condition seems to have no cure and it seems to culminate in the eventual death of the trees. 

[Jaboticaba45]

I am not too sure,
But I briefly read about it in Bill Whitman’s book,
And his langsat died because of it

Have to read more on it
Though I haven’t got time with physics lab😔

[LangsatFL]

I am not too sure,
But I briefly read about it in Bill Whitman’s book,
And his langsat died because of it

Have to read more on it
Though I haven’t got time with physics lab😔

Jaboticaba45, while it is true that he did write about corky bark disease in his book his Langsat did not die from this condition.  The Langsat that did die under his care was his “Uttaradit” tree which died after he cut down a tree that was partially shading it.  The tree died from sun burn and there was nothing Bill could do to save it.  You might be remembering his Burmese grape that did indeed die from corky bark disease which was a total shame since that tree was the first to ever fruit in the continental USA.  Bill had a few interesting theories on corky bark disease but he also failed to find a solution to the condition.  He did mention that the condition is worse on trees grown in more shady conditions although I have personally not found that to be true. It seems that my trees get it equally bad in full sun and in all sorts of shaded environments. Interestingly enough, Bill’s Concepcion Langsat tree is still alive today long after Bill passed away.  That tree has survived all the freezes and hurricanes that came after he passed.  It shows that Langsats can be a lot tougher than other ultra tropicals here in Florida.  I have a large Langsat that flowered this year and it is also plagued with corky bark disease.  All the flowers dried out or were knocked off by crows sadly enough; maybe next year I will get lucky.  I also wonder if the corky bark had a hand in making the tree fail to hold any fruit.  Good luck on your Physics lab!

[Jaboticaba45]

I am not too sure,
But I briefly read about it in Bill Whitman’s book,
And his langsat died because of it

Have to read more on it
Though I haven’t got time with physics lab😔

Jaboticaba45, while it is true that he did write about corky bark disease in his book his Langsat did not die from this condition.  The Langsat that did die under his care was his “Uttaradit” tree which died after he cut down a tree that was partially shading it.  The tree died from sun burn and there was nothing Bill could do to save it.  You might be remembering his Burmese grape that did indeed die from corky bark disease which was a total shame since that tree was the first to ever fruit in the continental USA.  Bill had a few interesting theories on corky bark disease but he also failed to find a solution to the condition.  He did mention that the condition is worse on trees grown in more shady conditions although I have personally not found that to be true. It seems that my trees get it equally bad in full sun and in all sorts of shaded environments. Interestingly enough, Bill’s Concepcion Langsat tree is still alive today long after Bill passed away.  That tree has survived all the freezes and hurricanes that came after he passed.  It shows that Langsats can be a lot tougher than other ultra tropicals here in Florida.  I have a large Langsat that flowered this year and it is also plagued with corky bark disease.  All the flowers dried out or were knocked off by crows sadly enough; maybe next year I will get lucky.  I also wonder if the corky bark had a hand in making the tree fail to hold any fruit.  Good luck on your Physics lab!

Thanks! Seems like you know much more than me on the topic! Thanks for sharing more on the history of his trees.
I am amazed by what he was able to do.

[LangsatFL]

Jaboticaba45, yeah Bill had an incredible collection.  He was able to fruit every commercial ultra tropical fruit tree except Durian.  He was really close to fruiting Durian based on how large his Durio graveolens tree was before a hurricane killed it.  He said the biggest obstacle to growing these ultra tropicals in Florida was not the cold but the hurricanes that plague Florida.  He said that Langsat was a more reliable producer of fruits here in Florida than even Lychees and Longans.  Too bad there are no real shortcuts to getting Langsats to fruit faster in Florida.  I feel like it could have potential as a cash crop here in South East Florida if grown partially shaded and protected from harsh winds. My air layers of my large langsats seem to die shortly after I remove them from the mother tree; very few survive being removed.  Adolf Grimal also had large fruiting Langsats on his property. 

[TropicalFruitHunters]

I've been to many farms growing Longkong here in Thailand, and it seemed as if every tree had corky bark.  All big trees and still producing gobs of fruit.  It didn't seem to be killing any of the trees, but that may be different long term.  I think most farmers let it be, one even telling us it was more cosmetic than harmful and doesn't really affect production.  It is quite possible the disease is different from the one here in Thailand...similar, but maybe more complications or other factors are involved to be more harmful to the trees in Florida/Hawaii?

[LangsatFL]

I've been to many farms growing Longkong here in Thailand, and it seemed as if every tree had corky bark.  All big trees and still producing gobs of fruit.  It didn't seem to be killing any of the trees, but that may be different long term.  I think most farmers let it be, one even telling us it was more cosmetic than harmful and doesn't really affect production.  It is quite possible the disease is different from the one here in Thailand...similar, but maybe more complications or other factors are involved to be more harmful to the trees in Florida/Hawaii?

I have heard from growers in the Philippines that their Lansiums get this condition really bad also and that it also leads to a decline in tree health and production.  Perhaps the condition is particularly bad in Florida and Hawaii because both locations are not truly tropical.  Hawaii may not get arctic blasts but it is still not as tropical as say a place like Chanthaburi, Thailand.  I hear reports of Lansiums fruiting in less than 10 years all over the true tropics meanwhile this type of fruiting time seems to be quite rare in Hawaii with most reports I hear claiming to be more than 10 years until first fruiting and even up to 20 or more years.  Here in Florida only Bill Whitman and Adolf Grimal ever fruited Langsats in their respective groves.  Whitman’s vegetatively propagated Uttaradit Langsat tree took 18 years to fruit for the first time.  There was a fruiting Langsat I remember seeing at Fairchild garden’s Whitman Pavillion but I don’t recall if it had corky bark or not. 

[dingaling]

My wife and I have around 20 longkong trees in Darwin Australia and we have the corky bark issue as well. It seems to be killing our trees slowly.
 Our trees appear to grow a little better if shaded. We have had many trees with bad sun burn on the trunk and then the wind breaks branches off one by one.

[LangsatFL]

Dingaling, yes this is a very worrisome condition.  I am surprised more people don’t talk about this chronic issue.  I don’t think this is just a cosmetic condition since there is a clear decline that comes from this corky bark disease.  I tried using a combination of a systemic insecticide and a systemic fungicide and it seems to have prevented a slow decline one of my trees was getting but I don’t think this is a long term solution.  I have also noticed that the trees can do a little better in the shade but I also notice that they can also get even worse corky bark in the shade too.  Have you noticed any relief in the decline of your trees with any method you may have used to attempt to relieve them of this corky bark issue?

[dingaling]

I think its far to early to say if the poison i have sprayed on the trunk has had any effect. I will spray the trunks two or three times over the next few months and see if there is any improvement.