Jan 23 it was 10F,here in the Backyard and I checked the in ground trees today and no frost damage on the older trees ,that demonstrated cold hardiness in the past,and are in the open without Winter protection.
I have noticed that since Ira Condit writings,it was noticed that fig trees on the north east part of the US,do not show Fig mosaic symptoms?
And it is true ,today just as it was described.
My opinion is that the extreme cold in the Winter,kill most of the virus ,living inside the ,out of ground parts of the tree(trunks,limbs,etc).
Tho the virus was never (naturally)exposed to low Temperatures ,in California orchards,nor was it done in the Lab,to know for sure ,how much cold it can take,it does have a limit,of resistance,at which point,if over it will die.
It seems that the tree is more cold resistant than the virus,so in certain Winter,the tree can shed most of the virus,and be much healthier next Summer.
It can't totally become FMV free because virus specimen,can remain alive deep,in grounds,at the end of the roots where Temperature can be as high as 40 and 50F,at about 4 foot deep.
Yet it will take a lot of time for the virus to populate the tree again,in order to  cripple the plant.
This explanation,is the only way it makes sense,Why Fig trees in NY,in ground do not show any Fig Mosaic virus,as witnessed and recorded by many people on this Forum and others.
A handful, of my trees were exposed to -4F,0,4 and 8F,in the 1990s

Great eval, 

though I live in the Northwest region, I hope I get results like that but my trees have yet to be determined. I find comfort that your cold weather is almost the same as mine (only cold weather NOT rain).

Jennifer

Herman...I think you are on to something with the idea of the winter cold driving back the fig virus...I have a six year old Ischia Green tree in the ground from a seedling...and it is the only tree in my backyard that does not have a speck of virus...It has been exposed to 5 winters of cold, freezing weather  with relatively light protection(burlap/weed cloth/ plastic tarp),  and I think the cold weather may have been a preventative to the FMV.  I planted 10 other trees in my backyard last spring (all with FMV), and the test will be how they come out of this winter freeze, and maybe the next few winters....  "time will tell".

As far as growing in containers Herman my UcDavis Ischia Black and others in various size containers saw garage temps as low as 6-8 above zero and in the  very low teens for several weeks some years back.
Following season they still showed the same FMV symptoms but thats not inground.
Course growing in containers i feel the fig plant is much more stressed and makes the virus worse possibly.

 In my climate when my fig trees are stored in garage FMV is always there the next season with my plants in there containers despite garage temps often in the low teens.

Here is picture of 12 above on thermometer in garage one cold winter , i recall kicking a 25gallon pot to see how hard it was cause the top soil mix seemed frozen and i cracked the pot . 

The fig shuffle helps me in early spring to gain some extra weeks toward end of season.

There are probably several variables at play. There apparently are a few strains of the virus, and they each might have different cold tolerance. There is also genetic variablity in cultivars. Perhaps UCD Black Ischia is simply more prone to the particular virus(s) it is infected with. 

Of course in my part of the world the virus will always be in the trees. It's sunny and about 60* outside right now. It got down close to freezing a couple weeks ago, but not enough to kill the pepper plants still in the garden. Such cold weather is very unusual here.

That is interesting. I have notice the same thing but on the opposite end.   I keep most of my figs out in the desert and some of my figs also along the coast in CA.   I have the exact same figs in both places, some of which I knew had FMV before growing.   None of the FMV shows up in the desert where the temps exceed 100 degrees for a good 5-6 months of the year and into the upper 110+ for many weeks.  However, I do see the FMV on some of the figs in California.  It seems the ones situated on the parts of the property that get less sun have more of it too.  They are vigorous in both locations, but are definitely the most vigorous in the desert.   Also, it got much colder in the desert (down to 27 for several days) than in CA (mid 30's for a night or two), yet the fig trees in the desert were much slower to go into dormancy, and some haven't at all.

So, what you're saying here is that we may have one major advantage over "fig paradise"? It just keeps getting better :-) . I'm glad to hear this H2. Looks like you may very well be onto something.

I think I am in the early stages of what you started many years ago Vasile. I'm determined to trial alot of different varieties in my climate in attempt to see which ones perform best here. It's a long process isn't it?

My intention is to plant most of my trees in the ground this summer. I'll then just use mulch to protect as much of the trunk/tree as I can.

I even have plans to grow a select few of the most cold hardy ones in the fashion depicted in M. Pons book. Just beautiful the way he grows his trees. My plan will be on a much smaller scale of course. And will be more of an experiment than an intentional orchard. I won't train my trunks to be as tall and will have to protect the trunks for a few years at least I'm sure.

Sorry for getting off topic though.

Gina:Yes you are right:Because there are more than one kind of FMV,or Fm Disease,some fig trees grow just fine and some as Black Ischia,are a loss,doesn't matter how much care is given.
And  also,viruses resist more or less,to excessive Frost  or excessive heat.
It seem that the fig trees growing in ground in NY, have mild strains of FMV,and not the  virus that Black Ischia suffers from.
I can see in my case,that slowly but surely,climate here select the specimens that can survive here from the ones that will not,so in a few decades,only FMV tolerant ,and frost resistant cultivars will remain.
It does not mean they will be free of FMV,but ,they will not show any,when just looking at them.
I think that is what happened to the trees in the NY area,growing in ground.

Most virus activity in plants is higher with higher temperatures to a point at both extremes.  Here is a paper that discussed elements of this:  http://www.apsnet.org/publications/phytopathology/backissues/Documents/1995Articles/Phyto85n03_286.pdf

One more reason why I will not move from the Fun Center of Ohio! What you are suggesting is that virus-free figs might be started from these cold treated trees.

Very interesting.  I had a feeling that very cold weather might affect the FMV virus.  It has been my observation that all the local trees growing in my area are either virus free, and, symptom free, or, both.  All these local trees are healthy, and lush, and not weakened by any virus, or diseases.  However, a large number of these trees never ripen figs before the onset of cool weather.  Some trees do, but too many don't.  That's probably due to variety vs. local climate problems.

Having trees that remain symptom free is my goal.  That's why I ask all sources if trees are infected.  I cancelled an order from Ison's, because they told me their stock comes from  West Coast suppliers.

After reading what Herman and others have to say...connect the dots.


Frank

I have no evidence to prove what I'm going to say, but prehaps the extreme cold helps de-activate the virus and causes it to go dormant to a point where the plant or tree is actually able to fight off the infection even though there is virus in it still they just are able to be as active as they used to be.  If this is the case then it would make sense that even if the virus is dormant in the tree it has now been given an edge that it can resist the virus easier because the plant grows faster and stronger than a dormant virus.

I think I am just saying what you are Herman but instead of saying kill I am saying dormant or de-activated, hope you don't take it as an insult.

so in theroy would it be possible to take cuttings from over winterd trees in these colder climates and that cutting not have a spec of fmv due to the cold. if this is in fact the case then any when said cutting is rooted it should be all or mostly fmv free. if this in fact the case it would be much easier to get fmv free strains in a controlled cold lab set up. i would like to get samples of FMV to run some studies on at various temps and observe the strain under a microscope. if this could be done to pinpoint the exact temp to kill the virus as well as the exact temp to cause tissue damage on spicivic kinds of figs then the fmv could be isolated or beaten all together.

if certin british sceintist (alexander flimming) did not ask "what is this fungus" we would not have penicillin today. so this observation herman may just be the start of a breakthrough for the fig growers. it certaly has my attention and i am going to run it by my cousin in denver he is a neclear physiscs guy for nasa (alot smarter than I).  and hes is wanting to get some figs for his new house and has asked me to help with that.

Dave,:In Theory yes,but,there is a possibility,that might make it not possible.
That is,:
If the sap,keep flowing from the roots to the tip of the plant and back,even in small quantities,(being in dormant stage),yet if the sap still flows back and forth a little,then virus can be transported continuously from roots to top of plant,so when one take cuttings they still have some live virus in them,that was recently brought to the top of plant.
Of course the frost will keep killing some of the virus,but,the chance is there to have some remaining alive in the cutting.
Overall the plant thrive any way next Summer because the amount of virus in the plant was diminished.

Edit Note:I am not sure if sap,flows during dormancy,I just suspect it does it much slower than in Summer,but I can't say ,yes or no,and am waiting for someone that know the answer on this one!!?

My thoughts on this matter are every living thing has  survival gene's. It's always changing to adapt to climate and conditions. If a plant such as a fig tree is put in cold area it has to change to survive. During this process, it's kinda like giving the plant a work out at the gym. So it must get stronger, and by doing this, the fmv is handle more easily. I would think that fig trees that have been growing in NY for many years are much stronger. Plus these trees were brought over directly and planted here and maybe not exposed to other fmv on the west coast.


luke

Are not the fig plants roots infected with FMV and if the roots are infected then the roots go down where temps are relatively warmer for virus survival? It is a question rather than a statement.

Yes the temps are warmer under the soil so fmv must be present there.

but for sake of argument. sap i am sure still flows during the dormant state as one would guess at a much slower rate. but if low temps kill off the fmv then cuttings could be taken and put into cold storage. now the trick would be to get a temp low enough to kill the virus but not damage the tissue. now that we are talking about cuttings free now from the fmv source (the roots) then with the virus gone any new roots on the cutting should be fmv free as well as the cutting itself. thus giving a fmv tree. this semms logical but i am sure cant be done with all figs but only the massivly cold hardy ones.

now here is the bigger problem. say you can get a 100% FMV tree. how do you protect it from contamination from another tree. how exactly is fmv transmitted from tree to tree. i have read and what i have found is that nobody knows for sure. the most popular blief is mites. or fmv could simply be part of its genetic code (like cancer to humans) and only needs activation by an outside sorce. i dont know just a stab in the dark there.

I think this method of producing a fmv free tree may work under the right conditions ( it is worth the time to test at least) but until we can figure out what causes fmv and stop it infecting other trees it may be pointless. but then again if you have fmv free trees it may help determine how fmv is transmitted.

anyway its worth looking into with some simple test.

Herman you ask in last part

Edit Note:I am not sure if sap,flows during dormancy,I just suspect it does it much slower than in Summer,but I can't say ,yes or no,and am waiting for someone that know the answer on this one!!?


Tapla i think it was mentioned that as tree goes dormant which there are several stages of dormancy the sap transforms itself and sheds something like water or sugar or something to that effect and has antifreeze type properties to help the plant sustain life thru winter.
One can cut a plant thats fully dormant like the ones in my garage and there is still moisture at the cut but its no longer the milky white sap its clear and does not run as if pruning in seasonal months.
So it seems the sap has changed properties white to clear just not bleeding (running) like we see during the season when cut.

From what i read and cannot recall where cause at one time i was into this FMV stuff but the virus is actually in the cells of the plant and in the UcDavis Ischia Blacks case which probably has several different strains of the virus it was mentioned that in severe case of FMV it will dramatically slow
down the multiplication of these cell which play a big role in the plants growth.

Never the less im stubborn and the UcDavis Ischia Black cultivar i will always seek more of them in trades.

This is a really cool discussion.  I have a few unknown NYC cuttings that I started this fall.  It will be very interesting to see if any of these cuttings display FMV in the warm, humid climate of Houston (I'm assuming of course that the mother tree did not display FMV).

There is a very good explanation of how figs survive winter here.
http://planetfig.com/articles/fareng2589.html

I noticed that FMV is now suggested to be in a new group called Emaravirus  http://www.mdpi.com/1999-4915/4/9/1515/pdf and to get one of these to show symptoms in leaves, they had to grow it in a heated greenhouse. So you may be on to something Herman, maybe the virus is able to move rapidly cell to cell only over certain temperature ranges. Just a thought.

Herman,
I have been collecting some of those NYC (healthy) fig trees for in ground trials. I don't know if they are virus free, but they don't have visible FMD symptoms (and they are aggressive rooters). Hopefully in a few years I may be able to comment on your observations of the possible reduction of FMD symptoms, from in ground planting in colder zones. I will be planting several purchased varieties (some with visible FMV/FMD) along side the NYC varieties for comparison. One way to test your observations would be to grow plants from cuttings of the suspect trees and observe the vigor (or lack) of the resulting plants. Thanks for posting this topic, It adds another item for my observations that may be beneficial in the future (food for thought).

H2-I still like your theory that trees on the east coast originate from isolated private gardens in Europe instead of commercial sources in regions where Aceria ficus is common. And that once here they do not become infected because the pest could not adapt as well as the tree to a cold and rainy climate. This is supported by the fact that FMV was not discovered until 1933 and the disease has not been observed to spread without the mite (or grafting). It is exciting to think that we may live inside a fig refuge.

But that still does not account for the assertions from reputable sources that essentially all fig trees trees carry FMV. Perhaps the varieties which survive longterm in a harsh climate have resistance to the virus like Ficus palmata hybrids are known to. Maybe they only have a single strain of virus which does not show on its own. Maybe it is that trees often are frozen back here and leaf out later so they grow mostly in hot weather when the virus is deactivated and the tips are healthy. Or perhaps the virus is damaged as a result of the complex chemical changes and deep cold that the virus is exposed to and is beaten back like you now suspect. That theory does best explain why so many trees here seem to be completely healthy and are apparently the exception to the rule because it would need to happen continually. I think the only way to know for sure would be to test them and see if they are in fact virus free. Which I do not want to do because it involves raising Aceria ficus or spending a fortune to have it done.

Great thoughts on an interesting topic.  If plant material continues to be sold, exchanged, propagated, from sources known to be infected, this kind of discussion will always be a regular feature on forums like this.  Our forum members are asking bold questions that might eventually lead to greater understanding about FMV in all its aspects, but in my opinion, few if any will take the drastic steps needed to slow down, or stop the spread of the disease.  For example: will Dave Wilson burn all their contaminated stock infected with FMV....will UC Davis?  Get my drift?  Wood from warmer areas infected with FMV, will continue to drift into colder climes, because no one wants to destroy infected plants....period.

Threads like this may offer insight on how some growers can eliminate, or possibly suppress, FMV symptoms.



Just my thoughts.


Frank