is the goal, through heat treatment / thermotherapy.

There has been anecdotal evidence posted on the forum of fig trees with visible FMD, that grew healthier after the roots were subjected to high temperatures from solar heated potting mix, 130*F / 54*C and above, or after they regrew from the soiline after die back. It has also been my personal experience with a tree that was riddled with Visible FMD/FMV symptoms that produced healthy new growth from a root sucker which has been visibly FMD free for more than 2 seasons. I had also observed that many FMD symptoms were caused by nutrient deficiencies and or pH imbalance. 

Since FMD symptoms can also be caused by nutrient deficiencies, I've been testing different fertilizer combinations and mineral supplements including water soluble fertilizers to find balanced fertilizers with all the necessary Macro and micro nutrients, which led to a hydroponic fig culture experiment earlier this season. I grew a few different cultivars in a hydroponic system modeled after the General Hydroponics WaterFarm8 and they were very successful for vegetative growth, but I have had more success producing actual figs in the standard 5-1-1 mix with solid organic and dilute Water soluble fertilizers.

My search for water soluble and hydroponic fertilizers which were needed for healthy root and vegetative growth in hydroponic culture led back to a way of providing a simple stable environment for root heat treatment of actively growing fig trees. Thermotherapy is currently being used to reduce and eliminate viral infection in fig and other fruit trees through Tissue Cultured Meristem and plant Heat treatment but it is performed at lower temperatures on actively growing fig cultures for up to 2 months.

The fig plants in this test will be grown in a hydroponic nutrient solution for up to 3 months. The nutrient solution will be aerated and heated to a maximum temperature of 120*F but could easily be heated above 130*F. Once the roots are established the top growth will be pruned off to encourage regrowth from a subsurface node. The goal is to reduce or eliminate the infection of symptomatic plants, this experiment was originally planned for this spring but due to winter kill of the majority of my fig trees which included several FMV symptomatic plants, it was postponed

I only have a few cultivars that are still FMD symptomatic after balanced fertilizer treatment, and they will be included in this test, they are Violetta BR (Burnt Ridge), Beers Black Us (Unknown source) and Petite Negri EL (Edible Landscaping). The setup, updates and results will be posted in this Topic.

http://generalhydroponics.com/site/index.php/products/systems/waterfarm/waterfarm_8_pack/

Pete, thanks for sharing the attached PDF. Great info on sanitation.

Sounds like a great experiment to try.  How long will you expose the roots in the hydroponic solution to the elevated temps?

Otmani,
You're welcome.


Steve,
The roots will be exposed to the heat treatment for 2 -3 months. It will be initially grown at a lower temperature, then cycled to the higher 120*F temperature.

Very interesting Pete.  I'm quite interested to see the results of your tests.  I think it's particularly interesting for folks like us who grow figs in places where there aren't many other fig trees around.  For folks who are in areas where there are lots of trees around, it seems a bit futile to seek a tree that isn't infected (since if there are other fig trees around, reinfection would be expected, given the ubiquity of vectors).  But for those growing fig trees in relative isolation, then if there's a way to get an uninfected tree, maybe it'd be possible to keep it uninfected.  

Note:  I do realize that you're talking about symptoms (rather than documented infection), but I'm assuming that's because that's what you can observe without going to the expense of documenting the presence or absence of any of the viruses.  That's good enough for me in any case :-).

Sounds like a great test... I'll look forward to whatever results you post.

Mike   central NY state, zone 5a 

Pete my BM is still small, but I am very optimistic about my experimenting, if you remember, I grafted a tip of a cuting to a piece of root I severed from my large tree. The root was still in the ground when I did that graft and was in the ground to about 2 months ago or so when I dug up a larger portion of the root and plant it in a larger pot. 

Along with another one named Black Fig 1 from ucdavis, which also was grafted onto a living root, these two trees grew 3 times the others that I was able to root. Another black Fig 1 rooted and strugles and continue to strugle, whereas the grafted ones are growing well, showing very little sign of that darker shades in their leaves, but no deformed leaves.  

I know it is too early to sing joy, but I am still very optimistic.  By next year, I am pushing for that formation  needed for production, so I knocked most of the figlets... I am tempted to take yet another tip from it, and graft onto another healthier plant. I want healthy trees.  

I am not using any store bought fertilizer, about once a month, I put them to soak in my home made bunny chicken poopy water. Once they are well irrigated, I don't water them for a while, except they got rained on a lot this week.  They seem to have enjoyed the rain.

here are they
 

Mike,

I think it would be useful even if you were in a place where reinfection could occur.  Having the plant virus free of at least symptom free would allow it to grow faster and get larger.  It seems the disease is not nearly as much of an issue once the plant sizes up but with severe infections of the disease getting them to size up is very difficult and can take quite some time. 

Very interesting experiment Pete!  How long for the results to be known?

Your observation  that many FMD symptoms were caused by nutrient deficiencies and or pH imbalance is also interesting.  I planted some young fig trees in-ground in fertile soil and they seemed to grow out of their FMV symptoms.  Don't know if this means they were nutrient deficient or ph imbalanced  and never had FMD/FMV?

Exciting paper and potential.
Thanks for sharing.

Mike,
Thanks for commenting.
Yes, trees could remain FMV / FMD free if they were isolated in a colder environment, but for the hobby, treated trees would grow faster, healthier and yield sooner than severely infected trees regardless of their zone location.
Yes, My criteria is visible FMD symptoms, which includes mottled leaves, mottled figs, necrotic spots and nodal spacing.


Grasa,
Thanks for sharing the pictures and info.
Your tree looks like it is growing healthy with good nodal spacing, the fertilization schedule looks to be working well.
If successful, the heat treated plants would be able to grow healthier on their own rootstock with visibly clean leaves and better nodal spacing. BTW, I'm an advocate of Rabbit Manure, I've mentioned it in an older posts, that it was used on several potted trees and it did perform as good if not better than chemical fertilizers, but not many growers have access to it.


WillsC,
I have an obsession with nodal spacing of rooted cuttings for a similar reason. Its been my observation that when cuttings are provided with balanced nutrients as soon as they are rooted, they will grow visibly healthier with longer nodal spacing, which increases the future vigor of the tree (increased nutrient flow between leaves and roots). Without the added fertilization the cuttings grow slowly which decreases the nodal spacing and leads to slower growing young trees.


Pino,
The results should be visible in one (1) growing season, but the true test would be over several seasons, the treated trees should leaf out every spring with healthy FMD free leaves.
Its been my observation that trees coming out of dormancy often produce early deformed leaves, often without FMD symptoms, IMO this is actually due to nutrient deficiency and not FMD. The roots to the waking trees have not started to absorb the available nutrient and this leads to the deformed leaves. I've tested this theory by fertigating awakening trees. FMD symptoms in infected trees awaking from dormancy include deformed leaves and the typical visible leaf mosaic. Even in healthier infected trees, leaf mosaic is still visible with back lighting of the leaves.
I've been able to produce FMD mottled leaves in visibly healthy trees by simply changing the pH and reducing the available nutrients with a water soluble fertilizer. When the pH was restored and the nutrients increased, the leaves and growth returned to normal. The control trees that were furnished with balanced nutrients and a good pH range are over 4 feet tall and were always visibly healthy while the tests are less than 18" tall and are now just starting to put on healthier growth and increased nodal spacing.
.


Dale,
You're welcome

Pete,

Just zipping through the thread (in case someone already said it) but my understanding is the Black Madeira is a UCD period.
I am currently air-layering a couple. Just say it, and I'll tag your name on one.

Rafed,
Thanks for commenting.
I've edited the Topic and Opening Post (OP) to reflect the change. It was my original intent to make the distinction.
Thanks for the generous offer, I accept, I'll send you a PM.

It's done and it's yours. Give me a couple more weeks for it to grow more roots. I took a peak yesterday and saw roots.

It is rooting in a 2.5x10 deep pot.

Pete, this grafting thing is so new to me and I really did not know it would survive.  When time to transplant came, I did not know if I should cover the joint or not, as covering would make it grow its own roots also.  Would this beat the purpose of having it grow on something else roots?

First I just put a cup with wood chips to keep the joint from drying out, but I decided to allow it to whateve it wants, and yes, I see roots coming from the main variety.  It will be difficult to determine if suckers are from the main or from the rootstalk.  I guess, I better not send out an unknown purple for BM, huh?

The BM is almost 2 feet tall by comparison with others from the same batch of cuttings, it is just short of a Panachee graft that grew 3  feet tall. All others are about one foot only. I have dormant grafts that are alive, but never grew anything..just swelling.

Rafed,
Thanks.
I'll spend the time setting up the hydroponic planters and grow lights ; )


Gina,
Thanks for commenting.
Increasing fertilization to the tree will help to increase growth and health, but the effect will still be limited because of the viral infection. Good luck with your Black Ischia.


Grasa,
Grafting will probably get a larger and healthier root mass under the infected scion faster, but the scion still has the viral infection and over time the infection will travel to the roots.
I wasn't successful with any of my fig grafts last year, mostly because I didn't protect the scion from dessication, so I have to defer to your experience and success when it comes to grafting  : )
Continued Good luck with the young trees and grafts.

Great info and your experiment looks very promising. I look forward to the results and will just tag along here for learning purposes :).

Very cool I look forward to seeing what come out of this, would be wonderful to have a way to make healthy stable trees...

I have a rooted BM cutting from UCD. It has one big leave(for a cutting) and hasn't started active growth yet. But it has been outside in half day sun for a couple weeks and in dry air for at least a month. I just removed a fig that appeared on it the other day. If you want to add it, let me know.

Jeff,
Thanks for commenting.
Hopefully I'll have positive results at the end of the experiment. There is always something new to learn, especially from older topics where its already been discussed.


Gloria,
Thanks for commenting.
There is already a way to make infected trees grow healthier, by fertilizing with balanced fertilizer in a well aerated fast draining mix to establish a large root mass. This has its limitations due to actual viral infection, but under optimal conditions and culture the trees will be relatively healthier : )


Calvin,
Thanks for the generous offer, I'll send you a PM.  

Pete, Ischia Black is rare and in high demand now.  I have two that are small and growing slowly and that's all I have.  USDA at Davis would probably like some more also.  They only have one small tree at Wolfskill, mostly dead, had one new shoot coming from the ground about 12" tall when I saw it yesterday.  They have one more in a pot.  Pretty sad, hope you can come up with some good results and help spread this around.  I got both of mine from Tom (New England Gardener), indirectly, last year.  Maybe he has more this year.

Harvey C,
Thanks for Commenting and the contact.

Black Ischia had not been on my personal wish list until this root thermotherapy experiment to reduce FMV infection, there are many healthier hardier, more productive cultivars in circulation that are on that list.

It would seem that USDA at Davis could perform a proven Thermotherapy treatment to reduce the FMV cocktail and insure the continued availability of the cultivar, but its probably not financially prudent.

I am glad that you mention pH.  I do not care to check mine, although I should and even though I don't, it's is a very important part of growing anything in containers or hydroponics.  soils have more buffers etc and you are able to get away with more drift but sharing that trees with leaves showing symptoms of either fmd or perhaps it was just nutrient deficiency that was the problem, in either case it does no matter it just shows that the tree is able to uptake what it needs and responded.  The importance of this is do not give up on trees like this, better to check pH and nutrients before giving up because it could turn around easily with some adjustments, maybe it won't but it's worth a try. 

Chivas,
Thanks for commenting.
That has also been my observation, that making the adjustments in pH and nutrients have only been beneficial to plants exhibiting FMD symptoms.

The Fig Thermotherapy experiment has been set up using a Top Feed Hydroponic system with a Perlite / Calcined DE potting medium. The system is configured as "Drain to Waste" with a 5 gallon bucket as the Waste reservoir and a second 5 gallon bucket as the Nutrient Supply reservoir. Each 1020 tray can hold (8) eight 5-1/2" square pots or (4) #1 nursery pots when larger containers are needed.
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The System is modeled off the Botanicare MicroGarden Top Feed, The planter area is almost identical...
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 microgarden_drip_instructions.pdf     

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