Not enough Durian Discussion

[cassowary]

Hi all
Wonder f any of you can tell me what is going on with the latest flush on my sunan durian. Seem to have a lot of die off - tree seems otherwise healthy and the 2 trees next to it are fine



Is it a nutrient deficiency ??
Cheers
Jim

I am not surprised to see you post this in October during dry weather as to me it looks like damage from a herbivore.
From my research herbivores like drier tissue, "highly hydrated"/"wet" tissue makes digestion harder and also dilutes the solids they require. When I take brix levels thought out the year of leaves I can see the difference in how many leaves I have to add to the garlic press to get sap out. IMO the leaf's looks a bit shrunken, idk if only more water will help, maybe more OM and water?

IME Durian leaves in Optimal health should have an almost oily shimmer and feel to them, be quite long and wide and also have very low visibility of veins (not to yellow) and be quite thick not to papery. I don't know if this is possible in an orchard spacing sun intensity system though. Some secondary plant metabolites seams to be reduced in those kind of growing environments, eg. amino acids, fatty acids. I know people hate to hear that since it's very simple to setup and manage.
IMO Durio zibethinus does not benefit from intense sun in it's juvenile and intermediate phase. I am trying to study it's Ontogeny.

By the time the tissue reaches to the canopy top the age of the tissue or the ontogenetic phase will be mature and thus ready for FULL SUN (aprox max 12H a day for equatorial). And the root system would be huge by then and able to sustain sap during intense sun.
I think Ontogeny is also the reason why horticulturalist Dr. Richard Campbell climbed to the top of a huge Mangifera Caesia to get his graft wood, highest possible ontogenic phase, in the Fruit hunters documentary.
Why do old durian tree's produce smaller fruits? Why do flavor and texture change with age? Maybe when we have cut down all the old growth durian tree's for mono musang king grids we will realize the loss.  A friend of mine thinks Musang king is very inferior to many wild old growth durio zibethinus fruits. And Mon thong is pig food compared IMO. Pigs gotta eat well too!
Have a look at the native Borneo pig.

You can try a foliar spray of fulvic acid, it's meant it temporarily increase the brix level in the leaf/tissue and make the leaf and tissue less desirable to herbivores. Haven't got the data for that yet, just trying to get a good base of control samples now.

If you also have steam borers I would say the tree is on it's way out, IME borers come in at a late state of decline in health.
You could try and cover the stem with a film or put a contact pesticide inside the hole and seal with a plug.
But IMO if the underlying cause isn't corrected you will be in for a lot of intervention, if it's not already to late.

Borers are one of the reason I don't cultivate durian clones.
The borer infection rate have been different when I have compared farms with seedling tree's vs vegetive clones, higher borer infection in clones with a graft junction. Haven't seen a mature durian cutting or marcott so can't comment on that.
I know none want to hear it... But to me it's so self evident and probably reflect the current high durian price and low availability in Australia. And to use systemic pesticides is inhumane IMO since it also enters the fruit which unknowing customers eat. "Systemic" Relating to or affecting the entire body or an entire organism.
And this Malaysian farmer is rejecting clones for seed grown tree's:
https://www.youtube.com/watch?v=40k2nP0xkRs

Bayer are always a step ahead of researchers looking into toxicology of their products, but eventually some syn. chemicals are taken of the market but it's ok for Bayer cause they got 10-20 years of sales. And the cycle continues.

Does anyone else have Heavy Clay Soil with low CEC? If so what did you do to correct it? OM? Ca? Organic acids/chelators?
One part of our forest have Heavy clay with CEC 5.6 which could be due to the age of the clay particles here cause usually Heavy clay will have higher CEC from what I have been told.

Here's the soil sample if anyone is interested:




That is from a spot on the land that have not been cultivated. Only by Cassowaries


Peace

[brian]

My durian seedling that previously seemed quite healthy has been slowly declining since this summer, and is constantly under attack from spider mites.  I decided to let it sink or swim... I planted it into the ground in my greenhouse.  This will accelerate either its recovery or demise. 

[cassowary]

My durian seedling that previously seemed quite healthy has been slowly declining since this summer, and is constantly under attack from spider mites.  I decided to let it sink or swim... I planted it into the ground in my greenhouse.  This will accelerate either its recovery or demise.

I don't see a reason why the durian wouldn't survive in your greenhouse, and with proper pruning even fruit eventually.
Spider mites, maybe a foliar application of trace elements will help increase the leaf brix and reduce the mites. Idk what your soil ph is, but beyond 7 isn't to good for durio zibethinus and some topicals from that area, Bill Whitman have some good stuff about that in his book 40 years of rare fruit.

[Gone tropo]

Cassowary thats some interesting reading there and I think a lot of truth in what you are saying.  Im also planting out seedlings as well as I believe like you say they are more hardy.

The only thing i would comment on is that when you say borers normally attack a tree on its way out, this is my biggest most healthiest vigorous tree that they attack they tree is certainly in good health. they also attacked it last year and the tree has mostly healed over those deep scars from the borers and continued growing. Im confident that this borer attack wont damage the tree too much if its the same thing that happened last year.

[brian]

I don't see a reason why the durian wouldn't survive in your greenhouse, and with proper pruning even fruit eventually.
Spider mites, maybe a foliar application of trace elements will help increase the leaf brix and reduce the mites. Idk what your soil ph is, but beyond 7 isn't to good for durio zibethinus and some topicals from that area, Bill Whitman have some good stuff about that in his book 40 years of rare fruit.

Not sure, I believe I have fertilized it appropriately and added garden sulfur to lower ph.   Perhaps it is getting too much water, I'm not sure what else it could be.  If it dies, I'll try again next year and try different soil mix, fertilizer, additives, watering...

I don't even like durian so this is just for the challenge of exotics

[cassowary]

gone tropo, I observed one of our "healthiest" Rollina getting hammered by borers in the dry season, which I assume is due to the dryness of the soil, so during those months I assume the health of the tree went down considerably, maybe your durian had some form of sudden environmental stress? And then just healed up once it got corrected.

I am not to good with identifying insects but I know some borers come in when the tree have living cambium and some when there is patches of dead cambium and that's where they bore. The ones that go through living cambium is probably very hard to stop, they do it to strong endemic plants here even.

At one durian farm it looked like the borers where killing his trees but on close examination I could see the wood where they where boring where already dead, so the tissue died before the borers came in this case cause they had not bored where the cambium where living still. These where approx. 30 years young mon thong graft clones, so they where coming to the end of their economic life. Another farm I went to at approx. 40 years had low health in their mon thong trees so it seams that is cut off life time. While seedlings on both farms looked healthy and still producing well. Even though those  seedling also got damages in cyclones.

If the tree got the borer I would try and keep it short cause the structure inside structure might be compromised.

Yay tropo, keep the seedlings going, we gotta plant lots to find the ones that love it here.

Brian,
Anthony Lamb, mentions in his book Fruits of Borneo that one of the natural habitats of Durio zibethinus is peat swamp forest so I would not guess you are overwatering. Hey maybe if you get a fruit of that one you will start appreciate the heavenly durian flavor more!

[Gone tropo]

Cassowary i will keep an eye on it however it can not be related to drought as i hand water my trees religiously if anything i would say the soil is over saturated compared to dry.  I did some googling and something mentioned about borers thriving in a very high nitrogen environment, i certainly would have a very high nitrogen environment around my trees

[pagnr]

What about other tree species around your area, are they subject to borers ?
Around here Citrus are subject to Elephant weevil larvae borers, in a feedback loop maybe of physical damage / root rot.
Probably a host of other possible candidates in your Wet Tropics area, jumping across from native trees ??
There is some thought that stressed trees are more attractive to pests.

[spencerw]

cassowary your tree companion comment reminded me of a conclusion I made a couple of weeks ago. As far as I can tell our best fruiting durians on the island are grown on sites where huge mangoes worked the soil previously. Every good durian had a mango work the site for 50-100 years. Looking at the soil that mangoes create i can see the fertility is very high in comparison to where mangoes were not grown, these are inferior wild mangoes so most of the fruit just rots under the tree, creating massive amounts of fertility. And some mangoes are native to borneo, where durians are also native. Most of the mangoes here are indica but I can assume the genus works the soil similarly. I've yet to take a soil sample under the massive durian tree. But I do want to soon to compare to the soil on my site.

[cassowary]

Cassowary i will keep an eye on it however it can not be related to drought as i hand water my trees religiously if anything i would say the soil is over saturated compared to dry.  I did some googling and something mentioned about borers thriving in a very high nitrogen environment, i certainly would have a very high nitrogen environment around my trees

Maybe when "high" amounts of Nitrates are present, Calcium and Silica is reduced and it makes it easier for borers to damage to the tissue... Silica might wear out their chewing organs faster or something like that.

Pagnr, I am happy our citrus isn't affected by borers "yet'..
Soursop and Rollinia are the ones that I have noticed get affected. There is one native tree species that have so much borer holes the trunk looks like a swiss cheese almost, but it survives. I'll try and get an image up, it's quite extraordinary.
Maybe cutting them out would help?

We got something that looks like the Elephant weevil that are often on the foliage of durian but haven't seen any holes in durian wood yet, only scrape marks on young tips. Do weevils do that? Or do they only drill?

spencerw,
Wow that is such a beautiful and healthy tree!
Yes your onto something here, maybe cause there's so much biological activity under the mango it creates a soil that leches very slowly despite rain and high temp. I have noticed Mangifera indica have dense canopies so the soil might have been in heavy shade for many many decades reducing turning OM into C02.
I planted one small durian under a huge mango tree and it's growing well despite low sunshine, will see how it goes when the mango is trimmed eventually.
I think you got something here since mangifera indica would be very close to a "natural habitat" companion, rather then using exotic plants from other parts of the world. Focusing on recreating natural durian habitat would probably bring some benefits.
Petai, keranji, shorea, mangifera, dipterocarpace etc..
And can see they planted some ginger species under the durian, might be beneficial too.

Peace

[pagnr]

We got something that looks like the Elephant weevil that are often on the foliage of durian but haven't seen any holes in durian wood yet, only scrape marks on young tips.
Do weevils do that? Or do they only drill?

Yes the adult weevil does oblong oval scrapes on twigs and branches of Citrus.
Pretty sure the drill holes are the larvae exit holes, so two life phases.
On really big trees you can't see the adults feeding, and you can't hear the larvae tunnelling out.
As they say "see no weevil, hear no weevil"

There is one native tree species that have so much borer holes the trunk looks like a swiss cheese... Maybe cutting them out would help?
Hard to say, could be a completely different bug, some can be pretty specific to their hosts.
If it is the same pest, it might help. Weevil holes are pretty much about pencil diameter here.

There are known links between weevil species and phytopthora.
 https://crec.ifas.ufl.edu/extension/citrus_rootstock/rootstock-literature/2003.%20Graham,%203%20PLt%20Dis,%20Rtstk%20Diaprepes%20Complex%20with%20Phytophthora.pdf

[fruit nerd]

Durian are flowering around where I am. Fingers crossed for a good year. Had a couple of dry periods this year which should help stimulate flowering I believe.

[cassowary]

Ohh then it might be that weevil doing the branch damage to some young durian tree's..
Weevil and fungus, yeah seams possible.

We only have tiny flower buds.

[jimreevescairns]

Thanks for the replies - particularly your detailed answer cassawory!
Have had fruit spotting bug and one called helopeltis suggested.
The tree is fairly mature - almost 4 m tall and the other leaves look ok.
I’ll spray it and see what happens. The rest of the leaves and tree look pretty healthy!
Cheers
Jim

[jimreevescairns]

Hey Fruit Nerd
Check your inbox re the grafts
Cheers
Jim

[fruit nerd]

Hi Jim, have replied. Had a busy week so not sure if I missed your message earlier or whether the notifications weren't working properly. Hope I'm not too late.

Interestingly, I managed to pick up a Durio macrantha today. Pretty happy with that. Starting to get a nice collection of durians.

[cassowary]

fruit nerd,
I read a book from MARDI about the Durio genus and they affirm that "Durio Machrantha" is not a separate species from Durio Zibethinus, it's is more likely a "wild" Durio Zibethinus according to them.
It's in the Durian of Malaysia eBook.

They make that claim based on the flower, leaf and fruit characteristics. To me it's so strange Kosterman would have separated the species if now there is some consensus against that. Kosterman for sure knew durian inside out.

I have seen a large seedling grown from a D. Macrantha seed and it looks like a Zibethinus.
I have noticed that some of my Balinese durian seedlings are very compact and dense in growth habit so there's huge difference in phylotaxis in Durio zibethinus and that type of genetic material might have the cyclone advantage that "D machrantha" offers.

And in the same eBook they say wild durians can be find on very nutrient poor rocky areas with vertical movement of water... I always thought durian needed high levels of nutrients in the soil... Maybe wet rock is enough or preferred??
And they also say they are found wild in shallow peat moss swamps, wouldn't that kinda rock the boat about Phytophra palmivora being the main disease for Zibethinus.
So here we have one example of extremely low organic matter retained and the other with extremely high levels of OM in the acidic peat moss.
I have observed that huge amounts of water is key for growth of Durian (sprinkler going 24/7 365) here but haven't figured out the ultimate soil substrate.
I wounder how or if one could replicate a peat moss swamp in a 10L POT??

And Why would Lime help durian? or getting the soil PH to 6.5??  I know Peter talks about this and local farms does the same but to me it seams contradictory to the botanical habitat data. Albrecht method might not be applicable to "swamp" or humid area soils.
I am trying myself with lime on some tropical water lowing trees to see what the effect would be.

And Peat moss can eventually turn into anthracite https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/swamp-soils
It seam our coal reserves where filled with thriving swamps long time ago.

One year ago I dumped one wheel barrow full of moist beach sand on a 1.5m short durian seedling and it have not affected the plant negatively. And there would have been more sodium and chloride in there compared to the native soil.
Next I am gonna try with a load of undiluted salt water.
And some other ones will get diluted salt water in different ratios cause to me it does not seam right about Durian being so sensitive to salinity.

[fruit nerd]

Thanks for the information. I agree that the seedling looks like a Zibethinus. Still happy to have it, regardless of its classification. Definitely aiming to get a wide diversity of durians.

[Finca La Isla]

Cassowary, where did you get the Malaysia e book?

Perhaps durian is pretty adaptable. My observation of a ph of 6.5 being desirable is based on being told at farm stays on Penang and Sabah that the soil where the durians are growing is 6.5. They worry about fungal root diseases and in general high acidity favors such problems.  Having said that I haven’t personally seen root disease problems here in durian like we often see in avocado.
Anyway, durian is being planted in varying conditions here in CR.  A friend has fruited a Mongthong at more than 1000m. Ph probably ranges from 4.3 or so to 6.5 in varied climate situations.  Lots of seedlings and selections from Asia. Pretty decent seedlings are now being grafted and distributed locally.  We are growing 4 of those as well more seedlings from Penang and Sabah and around 10 well  known Malay and Thai selections.

La Niña has given us a very dry year that has been great for fruit production overall but made it complicated for planting.  We are having to hand water some 20 trees that were planted when we expected the ground to stay wet but…
We had a terrific mangosteen season of 1500kg and lots of other important fruits as well. But the most interesting is what has happened with durian.  The dry season started two months early in December. There was already some durian fruits on the trees that started to ripen around April while the trees were flowering again.  Basically that pattern has continued all year.  Light flowering every few weeks with a trickling fruit drop that has continued up until now.  Every month has seen production!  The last fruits are still on the tree and the trees are flowering again.  So, we should have durian for another week or so, then get a break until February when we should get the fruit drop from this flowering.
Peter

[Gone tropo]

Peter what do you consider a dry year ? How many mm of rain have you had so far this year?

Fruiting a monthong at 1000m that is the highest I have heard of, would love to know the average temperatures for that place as well as absolute minimums, that must be on the absolute margins for a durian.  I had 95% leaf drop on two of my trees this year at temps of 8.4 and 8.9C

[fruit nerd]

Wow, that's quite amazing. None of my trees dropped even a single leaf despite, though as mentioned before, my minimums would not have been as low as yours. Micro climates make a big difference. On the positive side of the cold nights, I've seen a couple of lychees loaded with fruit.

[Gone tropo]

Yeh mate they were cold burnt to a crisp, leaves fell off in massive amounts over the following days.
Both trees are now bouncing back strongly.  Yep the cold winter seems to have triggered a good year for lychees nearly everyone with lychee trees have good crops......until the birds get them if not netted.

[Finca La Isla]

At 1000m elevation in the CR Central Valley it probably never goes below about 15c.

Rainfall in my area on the southern Caribbean coast has good distribution.  Statistically the wettest months are July and December and the driest are September and March.  That pattern can work to give us two durian harvests during the year.
A very dry year is about 2meters of rainfall.  A very wet year could be more than 5m!.  3-3.5m might be typical.
Peter

[Gone tropo]

Peter our main durian growing areas here in Nth Qld are wetter than that however rainfall here is much more seasonal with a massive wet season and a drier season.  For example Cape tribulation averages 4068mm per year with peak up to 6655mm per year, Babinda averages 4265mm with peak of 7040mm per year and Tully averages 4085mm per year with peak of 7898mm.  However I think when you look at Penang it has a much drier climate than this only averaging around 2500mm per year and they produce arguably the best durian in the world. 

[cassowary]

Peter, the Durian book is packed with info, really good! And the images are stunning!! Seriously some of the rare durian species have magnificent flowers.
If you have an android or iphone then you will be able to log into this Malaysian eBook store app with the details I got, I'll share it with or anyone else. The app is called e-sentral.
https://www.e-sentral.com/book/info/123036/DURIO-OF-MALAYSIA
Anyone just PM me. I like to share and this one was made by a gov agency from tax money so should really be free.

1000m, that must be a world first for a Zibethinus in cultivation.
Ok thanks Peter, so it's more to reduce phytophra palmiviora (sorry for my spelling) then anything else. Maybe that 6.5 ph that they found is when durian is growing outside of the peat swamp in richer clay or alluvial spots.
Did you ever notice anything significant after that you started applying calcium carbonate?

I wounder how a rock mineral based potting mix with flowing water will affect root rot incidence.
I'll have to do some experiments.

Interesting info regarding the warm water current, When I where in Ecuador I heard that James and his family at Guacuyacu had 4 flowering events during a la nina period if I am not remembering it wrong.
So amazing to hear you are getting a long season!
Durian flowering for us have been very low so far this season, and no lychees either.. Jackfruit have been dropping fruit  for 12 months now which is strange for us so maybe the warm water current is affecting us in that way here. Or maybe cosmic rays?? According to Dr Svensmark they are the drivers of cloud cover and thus the drivers of earthly ambient temperature.
https://www.youtube.com/watch?v=EpDDqGqN16s


http://www.bom.gov.au/climate/enso/#tabs=Pacific-Ocean&pacific=History&enso-impacts=La-Ni%C3%B1a-impacts

tropo. I tried to access that data from BOM but I can not find it, do you have a link to the historical data search?