Heat treatment cure for FMV

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zone5figger

Registered:1395082963
Posts: 250

Posted 1422976446	Reply with quote #1

Heat treatment is widely used in nursery practice as a way to sterilize living plant tissue of persistent viruses. This technique is typically employed with tissue culture propagation, where a very small apical meristem 'micro-cutting' is subjected to high temperatures for a given period of time. This kills the viruses without killing the plant, kind of like an immune system fever response. The plant tissue is then grown out into a 'clean' plant. There have also been anecdotal growers' reports on this forum about fmv(fig mosaic virus(es))-infected plants getting cured by high and low temperature extremes. I'm quite curious to hear any other reports by those who have had that experience. As I grow out my crop of fig starts, I'm seeing the signs of fmv on 60-75% of the plants. Some of the 'clean' plants are one of a multiple set of the same variety in which others display fmv...others I've received the same variety from multiple sources, and one source's plants show fmv and the other does not. Most of the in-ground 'Unks' I've received have grown out clean foliage. Is fmv truly as ubiquitous as some folks claim? For my eventual in-ground trials, I need to grow out the healthiest plants possible, so it seems important to address this issue. Perhaps for others in warmer climes, fmv does not impact the plants, but for zone 5, I feel I need every advantage. Although I don't have the laboratory setting to do tissue culture, I have started a heat treatment experiment with some of my duplicate starts most heavily afflicted by fmv. A little bit more of a hill-billy approach, but using some scientific methods; careful monitoring with pyrometer, control group. These plants are being placed next to a consistent heat source, my woodstove, for a bit of tough love: 24-36 hours of high 135F + temps. The first one I did this with defoliated, but now 3 days later is starting some regrowth which seems healthy thus far! I don't want to open a can of worms with this discussion, so no opinions, conjecture, please. Previous discussions on fmv seem to sometimes get a little off track, and I would like to just stick to the topic. Thanks! __________________ Jesse- zone 5, 1000' elevation

Speedmaster

Registered:1404377112
Posts: 385

Posted 1422976768	Reply with quote #2

Yeah for an extended perioud of time you can kill viruses and bacteria. I do cook with this method using water baths, thermometers, and plastic bags. Sous vide I think its called Where you cook it at low temperatures in an extended time to kill bad bacteria and viruses. What remains is very very tender and juicy meat. ;) __________________ Weather: Winter: 10C+ Summer: 42C+ Growing: Syrian Unk., Atreano, Egyptian Unk., Lebanese Unk., Col de dame Gris, Beall, Negronne, Ronde de bordeaux, Brogiotto Bianco Wish List: Panache.

rafaelissimmo

Registered:1335639347
Posts: 1,473

Posted 1422976859	Reply with quote #3

Ascpete, who is away for the winter, is doing the exact same trials. Pete S. It would be useful for both of you to compare notes and share with the forum, he won't be back til spring I think. __________________ Zone 7b, Queens, New York

zone5figger

Registered:1395082963
Posts: 250

Posted 1422979696	Reply with quote #4

I believe this is the thread you are mentioning: http://figs4funforum.websitetoolbox.com/post/fmv-free-uc-davic-black-ischia-and-uc-davis-black-madeira-7040439?pid=1285258128#post1285258128 Seems like it was never updated with results, unfortunate. __________________ Jesse- zone 5, 1000' elevation

aphahn

Registered:1354927274
Posts: 321

Posted 1422988467	Reply with quote #5

Bass also mentioned this when he interviewed the Russian fig researcher. http://figs4funforum.websitetoolbox.com/post/show_single_post?pid=41259085&postcount=11 I would suspect that the best results would come from holding at high temps for several weeks and then tissue culturing a bud. __________________ Andy - Zone 6a Lat 39.9º N, Alt 5390' Westminster CO ⚘ Scion List

hoosierbanana

Registered:1287901146
Posts: 2,186

Posted 1422991626	Reply with quote #6

The idea behind thermotherapy is to denature the virus (cease replication) with heat (~95f) while the plant is still actively growing. The new growth now contains no FMV and is removed and propagated for virus free plants. That is my understanding anyway. Higher temperatures for shorter periods may not have the same result, I don't think the virus is actually destroyed and could begin to replicate again when the temperature is lowered. I have never tried either method, so keep that in mind. From my personal experience the combination of FMV and the fig mite is much more damaging than either alone. Infected plants grown without the fig mite can show fewer symptoms as time goes on, some cuttings from these infected plants will not show any symptoms themselves and may be virus free. The virus itself travels through the plant slowly from cell to cell, while the mite is extremely mobile by comparison and will spread symptoms to the entire plant. I think that is why freezing to the ground has a positive affect, it spurs rapid growth that the virus cannot keep pace with. There are several other viruses that may or may not cause any symptoms together or alone, FMV is scientifically proven to cause symptoms. Not every tree has FMV, that is a fact supported by many studies. Fig mite symptoms can easily be mistaken for mosaic, and they do spread FMV so can cause every tree in a collection to be infected eventually. At the same mite symptoms may be masked by more severe FMV symptoms. If you would like to read more about fig viruses I compiled some data from different studies here. __________________ 7a, DE

So_Cal_Mike

Registered:1351472531
Posts: 43

Posted 1422992371	Reply with quote #7

That was a very cogent explanation, thank you hoosierbanana. __________________ Sunset Zone: 21 • USDA Zone: 10a __________ Wish List: Lattarula

jdsfrance

Registered:1376988473
Posts: 2,591

Posted 1422999707	Reply with quote #8

Hi Zone5figger, In pots, fig trees can suffer lack of some nutrients and that leads to misshaped leaves and the grower thinking about FMV. I don't say that you don't have FMV, but just that everything you call FMV might not be FMV, but problems in the growing conditions of the trees. Try fertilizing more one tree in your test group. 70% of plants with FMV seems a lot to me . As already mentioned watch out for bugs as they can produce same bad looking leaves as FMV. __________________ ------------------------ Climate from -25°C to + 35°C Only cold hardy figtrees can make it here

schaplin

Registered:1392175246
Posts: 662

Posted 1423007216	Reply with quote #9

I think I need to see validated virus testing from an laboratory before I did the happy dance. Virus have a nasty habit of going dormant for a while and then making a comeback. I agree that many things look like virus that are not. In orchids we see a fair amount of fungus that makes leaves looked virus. __________________ Wish List: @Hmari, @Maltese beauty, @Col de Dame Grise, @Bryant Dark, @Lynhurst White, @Melcedonia Dark, @Panevino Dark, @Paradiso

zone5figger

Registered:1395082963
Posts: 250

Posted 1423239954	Reply with quote #10

Here's examples of the fmv on my starts- All these are receiving identical treatment to healthy plants like this one: __________________ Jesse- zone 5, 1000' elevation

hoosierbanana

Registered:1287901146
Posts: 2,186

Posted 1423242669	Reply with quote #11

Pic 2 looks like mites: pale spots and browning. The others look like FMV: vein clearing, mottling, deformity, stunted growth. __________________ 7a, DE

musillid

Registered:1327758167
Posts: 1,507

Posted 1423314890	Reply with quote #12

Thank you all for these posts. They are very enlightening. __________________ Dale non compost mentis in Zone 6a

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