I've had a worm factory for some time now and regularly mix worm castings into my soil mix.  It's pretty well accepted that worm castings improve disease resistance.  I had assumed this was related to root diseases, like pythium, that the microbes help prevent, but had read somewhere (sorry, I can't find the link) where they said plants grown in 10% worm castings developed natural pest and disease resistances.

I figured I'd try this if I ever had a fig with FMV and finally got my chance with a newly rooted Black Madeira cutting from UCD.

Most of you probably know that the UCD BM is well-known for having FMV, but I guess until you get one for yourself, you figure it won't happen to you, but start collecting figs and sooner or later, you'll see FMV.

I rooted the BM in a Rapid Rooter grow cube and then, when showing roots, moved it to a perlite/vermiculite mix.  As soon as it started showing signs of sprouting it's 4th leaf, I transplanted to a soil mix that had about 25%-30% worm castings.

Here's the leaf-by-leaf progression and excuse some of the glare on the pics, but I had just misted the plants before I took these...

Leaf #1 formed while rooting in the grow cube and is somewhat deformed with severe mottling clearly showing:

 

Leaf #2 & #3 both formed in the perlite/vermiculite mix and were pretty much the same as the first being slightly deformed with severe mottling:

 

 

Leaf #4 was just starting to show signs of opening when I transplanted it to the soil mix with the high concentration of worm castings.  This leaf was more severely deformed (perhaps from some transplant shock?) but is hardly showing any signs of mottling.

 

Leaf #5 has just sprouted and was the only leave that basically developed entirely while in the soil & worm casting mix.  It's still small, so was tough to capture, but it appears to be a perfectly formed three-node leaf with no visible signs of mottling, so far:

 

This was the only Black Madeira cutting (out of two) that survived, so I didn't have any "control" for the experiment and, even if I did, I probably would not have set up another FMV infected BM cutting as a control since I'd be more interested in attempting to cure the FMV!

That being said, it may just be the BM is starting to "grow out" of the FMV and the worm castings are not the reason, but based on my current results, I'll definitely try this again with any other cuttings I have that show signs of FMV.

Has anyone else tried this?  Did you have similar results?

Very interesting, thanks for your report!

In my case, I noticed that the figs are getting rid of the FMV when planted in ground. I add a healthy portion of the compost full of the worms.
So, maybe it is a difference between a pot/in ground or maybe this is an effect of worm castings or both.

Your Black Madeira has a bad case like mine. Mine has been in a pot until this year. Now that it is in the ground, I have been fertilizing organically and the plants are mulched with pine bark and straw. The soil is full of life, lots of worms working the soil. Now finally I am starting to see more normal leaves forming.

Mike in Hanover, VA

I might be wrong but, IMO, just like in humans, fig plants will show more virus if their immune system is compensated, as they get stronger the FMV lessens but that doesn't mean the plant grew out of it.
Various composts have different nutritious qualities, in this case, Worm Casting could be a strong booster for the plant immunity thus lessening the visible effects of the FMV to our eye.
Furthermore Viruses, unlike bacterial infections, are not curable but controllable. This is why I am convinced that FMV can not be completely overcome.

I have to agree with Aaron on this.  The virus is going to a dormant state until the plant gets stress again.

Your tree still has whatever fig mosaic disease (FMD) viruses it had before.  When you give it a healthy environment, it probably continues to show fewer effects of those viruses (than it would in a less healthy environment).  The point is:  give your trees a healthy environment.

Mike

By that logic/definition, then anything that is healthy for your trees is a treatment.  
                 Lots of sun:  a good treatment,
                 well drained soil:  a good treatment,
                 good mix of nutrients in the soil (such as those provided by worm castings, or many other approaches):  a good treatment.

I'm not disagreeing with you that worm castings provide benefits to fig trees.  I think anything that is beneficial for fig trees in general also is a good thing to do for fig trees infected with some mix of the "FMV" viruses (which by the way, just might be all fig trees).  Treating a tree well seems to help it to be less affected by these viruses.

Is there anything special about worm castings for reducing FMV symptoms, compared with other ways of providing a healthy environment for the tree?  I'm not convinced.  I've seen plenty of trees reduce their symptoms dramatically, following basic good treatment (improving soil drainage, correcting pH, providing a sunny locale, etc.).  I've also seen some get worse mosaic disease symptoms, in circumstances where I could find no proximal cause.  None of this is to say that worm castings are bad (I think they're good), but is there any particular benefit they provide for reducing FMV symptoms, compared with other ways of providing a healthful environment for you tree? 

Mike

To go along with what Mike said:

To answer the question, one would have to get a large number of trees of a similar variety and a large amount of worm castings.  Then you'd have to come up with an alternative amendment that is similar to worm castings in terms of N-P-K, moisture retention, etc.  You would grow enough trees to eliminate natural variation and apply worm castings to one group and the other amendment to the other group.  Then you'd let enough time pass to observe the effects.  This would all have to be done in a controlled environment.

I think everyone would agree that worm castings would be beneficial to most plants.  But I'm not sure it would perform better than the control. 

"Most of you probably know that the UCD BM is well-known for having FMV, but I guess until you get one for yourself, you figure it won't happen to you, but start collecting figs and sooner or later, you'll see FMV."

So I ask , Is it possible for someone to have a BM from UCD that is not infected with FMV?

I had to inspect mine from UCD. My only cutting went into the ground from day 1 last spring.  It did not show those exact symptoms. My Black Madeira had winter injuries and is recovering nicely.

The curling of those leaves is probably caused by afternoon temperatures over 100 degrees.

Compared to other figs, I must add that so far it has been a very slow grower for me.

 

Figaro,
Thanks for sharing your observations.

I haven't tried worm castings, but have provided a balanced fertilization schedule, fertigation and or micro nutrient supplements for increased nutrients to FMD symptomatic plants. Bronxfigs started a topic last year, http://figs4funforum.websitetoolbox.com/post?id=6414845  to which I posted my observations of a Petite Negri EL that was provided with an Ironite supplement. The documented plant put on a lot of healthy looking growth in a very short period of time. The Ironite provided added Iron, Calcium and other Micro nutrients that could be more easily absorbed by the plant roots.

The added nutrients provided by the worm castings may be the possible reason for the healthier growth. From tests this spring with simple fertigation, several  young fig plants that initially showed FMD symptoms have put on very healthy leaves and substantial growth by only maintaining a simple fertilization schedule with Macro, Minor and Micro nutrients. In my observations increasing the Calcium, Magnesium and Iron content of the growing media seems to be the major reasons for healthier growth. Its probable that plants infected with FMV, with FMD symptoms will benefit from increased vigilance of their nutritional needs.