FMV in figs: how serious?

Thank you!

@hoosierbanana I have a question about the mites that spread FMV, once I read that they canā€™t be spread by cuttings if the cuttings are dormant and if they are soaked in a bleach solution to kill any possible eggs. Do you find this to be totally true?

They overwinter in dormant buds, which are almost waterproof, or at least will trap enough air inside to keep the solution from penetrating. Iā€™m not sure how effective bleach would be even if it could get inside of the buds thoughā€¦

Grape growers use hot water treatments. Should work for figs but I donā€™t know if anyone has tried it.
https://www.google.com/url?sa=t&source=web&rct=j&url=https://ojs.openagrar.de/index.php/VITIS/article/view/4963/4752&ved=2ahUKEwis7P383a7uAhUNmeAKHcsoDmsQFjAGegQIDRAB&usg=AOvVaw3_0z2h9iE0fzxaOwsYfUUm

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Ahh I hadnā€™t realized they used the hot water treatment for mites, I knew it cut down on the fungal/bacterial load. I have plenty of extra cuttings, I might give it a go. I think Iā€™d just toss them in a pre-rooting tub, record viability, then compost.

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Do you mean that what may seem like future buds to people because they are so tiny that people may not notice them, they can have the mites in them as well?

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I mean soaking wonā€™t fill the buds with liquid, even the larger terminal buds. There are many layers of tiny leaves inside buds that are waxy and repel water.

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Hello folks,
I understand this is an old thread though it has been informative as my fig journey is just beginning. The first cutting I ordered appear to be infected with FMV that I didnā€™t know existed until two weeks ago. After reading post on this forum and Ourfigs this should have been expected.

My question is has anyone tried thermotherapy on cutting to kill the virus. I have read that it works for grape vine cuttings to eliminate mite infestations. For figs I only see thermotherapy listed in conjunction with shoot tip culture and it appears to take a lot of effort.

Any insight our direction is appreciated.

All I know is that thermotherapy is very hard to do right, and even if you do it right it might fail on at least some of what you are trying to clean of disease.

How old is this cutting.

The cuttings are arriving in the next day or two and will be fresh.

I never tried it but FMV is no big deal anyway. Most figs become asymptomatic. So I have bigger issues to worry about. Itā€™s like worrying about fig mites. Which cannot survive in my zone. So I donā€™t ever concern myself with them either. Itā€™s such a non issue.

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I know weā€™ve been over this before----but, no, itā€™s not a ā€œnon-issue.ā€ If the buds live, the overwintering mites inside the buds can also live. If you allow your figs to be regularly topkilled in the winter then, sure, youā€™ll eventually get rid of any mites that might be present; if, however, you preserve infested portions of a fig by protecting it from tissue-destroying freeze damageā€”and this can apply to either potted figs kept in dormant storage or to effectively protected in-groundsā€”then you can very much have mites in your cold zone. And you can have them for as long as youā€™re willing to protect the wood and ignore the mites. And even if an infestation does, for whatever reason, prove only temporary, itā€™s very easy to spread it to others if you carelessly share infested cuttings and plants while itā€™s ongoing.

The fig bud mite-infested cuttings I received in 2017 came from cold-winter regions of the eastern United States. How do you suppose this is possible?

I donā€™t want anyone to worry. But neither do I like so see people encouraging new growers to adopt careless attitudes about potentially seriousā€”and very easy-to-spreadā€”pests and pathogens.

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There is no way to kill the virus without killing the plant. An infected plant will always be infected, but an uninfected one can be propagated from it if plant growth exceeds virus replication enough because FMV doesnā€™t spread through the sap.

So thermotherapy puts virus replication down to zero, each new cell division cuts the number of virus particles in half until there are none in new cells. But the same thing seems to be possible in very vigorous growths that donā€™t show any symptoms, where a percentage of new plants propagated from them will not show any symptoms themselves.

Mites really are the main thing to be worried about, particularly since many people attribute their symptoms to FMV, or something else like fertilizer. They are very common, and can survive in cold regions on plants that are protected or stored inside. Nobody knows how much cold it takes to kill themā€¦

As far as precautions you can take against FMV and fig bud mites. Buy from established nurseries as opposed to collectors or fig specific nurseries, who may not manage either due to the belief that they are not a serious issue. A hot water bath may be able to kill the mites without harming the cuttings. Removing any terminal buds, which is where the majority of mites overwinter. And/or prophylactic sprays with an effective miticide after they begin to leaf out.

It is a lot for a new grower, and no surprise that many people choose to ignore or resist the issue.

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Thanks for the information. I live in zone 9b so it rarely dips below freezing for any real length of time. My goal is to start clean.

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This is the article that talks about thermotherapy for mite treatment in grapes and looked like it may be worth trying.
Mite treatment is grape cuttings

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Just an observation. Some of the older fig trees in our area are not protected over winter. Those trees are super healthy and I do not see any FMV symptom. It is possible that those trees are not infested. The other possibility is that, with our cold winter climate (can dip below 10F), the very young buds got killed above ground, maybe even one or two inches below ground. So those mites whatsoever would not survive. Also those older trees have large root systems and are very strong. Any virus survived canā€™t compete with the strength of the tree. So the virus may eventually get weakened and become insignificant. Not sure if the virus would disappear or just hidden inactive.

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Hi,
Apologies for interrupting this thread, but I have an MDDS fig that I bought in July that didnā€™t look great on arrival and has put on no new leaf or root growth. This prompted me to do a Google and having found this thread I fear my fig may have FMV and Iā€™d value your opinion. Iā€™ve attached a photo I took on receipt of the item.
Many thanks

Hi @Fignewbie , welcome to GrowingFruit!

That appears to be FMV and if so it also has the microscopic mites that spread the disease. And as a side note, it is not Fig Rust which growers often confuse with FMV.

Most fig cultivars are vigorous enough to live a healthy life in spite of FMV. The treatment is with elemental sulfur (e.g. Thiolux) - not calcium sulfide. Applications are made after leaf-fall in winter, at leaf-out in spring, and again mid-season for acute infestations.

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Thank you Richard,
Given that this fig never managed to open a bud or expand its roots into new soil in over 2 months of an usually hot UK summer, it appears to be struggling with the virus. Iā€™m worried now that my other 2 fig trees (a brown turkey and a brunswick) which were alongside it may have been infected. Iā€™d love to see the MDDS develop but in case it hasnā€™t affected the other figs Iā€™m leaning towards nipping any future issues in the bud and putting it in the municipal green waste, as although it sounds like fig trees generally grow out of it, any sort of productivity drop for a fig tree here in the UK is significant. Do you think Iā€™m over-reacting?

That is not a symptom of FMV interference.

I will add, that given the plant arrived with the disease is a sign of poor horticultural practices at the source. In other words, the plant might be weak overall due to prior treatment.

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Yes, I agree totally and needless to say I wonā€™t be buying from the supplier again.
Interesting re the lack of growth not being a symptom of FMV. Iā€™ll check the rootball out more closely to see if there is any indication of being it being rootbound.

Many thanks, Neil