Fig Mosaic Virus (FMV) Prevention and Control

**mountainfigs** · 04-20-2015, 09:44 PM

Great overview, Pete. Very thorough and useful.

This has been my experience too:

"IMO, many of the FMD symptoms that are attributed to FMV are actually nutrient deficiencies and can be avoided with application of balanced fertilizers, macro and micro nutrients and a better adjusted pH range."

I've never checked pH but my trees are typically well fed whether in ground or in pot, and if in pot then decently held in mostly peat and bark with ag lime added AND typically rooting in the ground through holes drilled in sides.

If FMV shows usually a stressor culprit can be found: too dense growing medium (lack of oxygen) or too much or too little fertilizer or water.

**Darkman** · 04-20-2015, 10:47 PM

Do all figs want the same pH level or do ones from different regions like different levels.

What do you think the optimal level is for most figs?

I seem to be able to grow nice trees that seem reluctant to bear many fruits. I have avoided fertilizers since I was afraid of having to much growth and no figs but even without fertilization I get lots of growth. Suggestions? By the way my entire fig growing area about 60' x 90' is completely and heavily mulched with about six inches of oak tree leaves and it is kept weed free.

Is there any truth that if you heavily prune a fig it will bear heavily the next year?

**Wisner** · 04-20-2015, 11:40 PM

Darkman, you may want to check the ph in your fig orchard and if it is in the acidic range adjust the ph by adding lime. Your fig trees will probably benefit from a more neutral ph, around 6.0-6.5. Pruning a fig tree will stimulate more new growth which should mean more figs produced on the new growth. They say it's better to prune some yearly instead of waiting several years and severely pruning them back.

**rusty hooks** · 04-21-2015, 12:16 AM

Last year I potted up (in a 15 gal SIP) a 5', what I believe to be "Adriatic"...taken from a mother tree as a sucker the fall before. All leaves were exhibiting characteristics of FMD...mottling, slight deformity but still a healthy tree. As the season developed I started taking daily photos of one particular leaf to see if there would be any change...and I started feeding...through the SIP and daily fillups....EC 1.5, PH 6.5...all season (hydroponic food...water nutrition). No change in the leaf, other than a darkening of the green indicating a good use of the food but the mottling did not change...same map.

The tree put on 2-4' of growth over the season, all leaves showing some mottling...but with good growth.
Now comes this year...and the first leaves come out...minor mottling...but only exhibited on one branch...and the rest of the tree...nice healthy green leaves with no mottling...yet....the door just opened to this season but the feeding indicated what I had suspected....the tree hadn't been fed prior to the SIP....and the mother tree has never been fed.....and with the stress of ripping it away from it's mother....stress + lack of nutrients

I'm following the cuttings I have of this tree closely. The mother is a notorious producer of good quality figs, shy of the open eye...but a good quality despite the FMD.

More yet to come...Thanks for starting this Pete

**AscPete** · 04-21-2015, 12:30 AM

Charles,
The pH for in ground fig trees can vary greatly, but the best range for nutrient absorption and growth is between 6.5 - 7.5.
For potted trees the same applies, but its usually easier to maintain at 6.0 - 7.0 pH. Figs also need increased Calcium, Magnesium and Potassium for good growth and fig production, I'm currently using Ironite Mineral Supplement which shows visible improvements in tree health and growth

Many fig trees are rarely pruned, which often results in excess vegetative growth and reduced fig production due to excessive # of branches. Establishing the scaffold branches and fruiting branches will enable easier pruning and increased future fig production, http://www.ourfigs.com/forum/figs-ho...-espalier-form

Since figs are produced on this season's growth, heavy pruning will result in the growth of many dormant buds which may or may not mean increased fig production. If the total # of buds (branches) are not reduced (pruned) the result could be excess vegetative growth and a reduced fig production.

**BronxFigs** · 04-21-2015, 06:36 AM

Until I joined, and read about this subject on a few of these Fig Forums, I never knew FVM/D existed, or, could infect fig trees. I would venture a guess that a very large percentage, if not all, the older fig trees growing (in ground) here in The Bronx, including the surrounding areas, Queens, Westchester, Brooklyn, Staten Island, etc. are all FMV-free....growing with, or without, nutrient deficiencies, etc. Local trees may not be great producers, are often poorly grown and maintained, and most are pruned incorrectly, but they are all clean, lush, and vigorous. In fact, the only fig trees that I have ever seen, showing symptoms of FMV, were in my collection. They weren't in my collection for very long, either. These mail-order trees were dumped as soon as the first signs of FMV showed on the leaves. I simply refuse to deal with any diseased trees, whatever the variety....but, that's me. Now, I grow only Tissue-Cultured trees, or, "clean" trees propagated from local sources. I am a fig eater, not a collector. I'd rather grow 3-4 great trees, than grow trees that perform poorly.

This thread suggests that with correct culture and proper nutrition, symptomatic trees will probably improve, health-wise....maybe. That's good news.

Interesting to read all the latest info and opinions.

Frank

**Harborseal** · 04-21-2015, 05:20 PM

Darkman, Oak leaves turn your soil acid so some dolomitic limestone will help.

Q* · 04-22-2015, 05:54 PM

Very nice post Pete. Really good information.
I wanted to ask....has anyone had first hand experience with FMV being spread by mites? I have over 25 varieties of fig cuttings from various sources that are growing out fine. Some started out beautifully with no signs of FMV and some that were slowed from the get go....now all of the small rooted plants are showing a little sign of blotchy leaves. They are all kept next to each other in 5 gallon nursery pots. Is it nutrition deficiencies or was FMV spread....

**hoosierbanana** · 04-22-2015, 07:27 PM

Fig Mites are the only way FMV spreads. Some of the other viruses can be spread by tools, or mealy bugs, but FMV is only spread to a different plant by the mite. These are pics of Fig Mite symptoms, they disappeared after treating with miticides and briefly reappeared on a couple plants that did not get good spray coverage (end of the row and tank). FMV was passed to some plants that had previously shown no symptoms.
Older affected leaves:

New healthy (Fig Mite free) growth:

Older affected leaf:

New growth:

Plants in the greenhouse
Definitive end to spotting symptoms 1 week after treatment:

FMV shows after mite symptoms are gone (vein clearing at 5 o'clock):

Browning and spotting caused by Fig Mite on aged leaves:

New leaves, one week after treatment:

Similar spots on figs of infested plant, "hairy" varieties showed spots on figs while smooth skinned varieties had very few:

Detecting symptoms is easier than detecting the mite itself, the pic posted in the OP of eriophyid mites shows them clearly, but on figs they are harder to see because of "leaf hairs", what gives the leaf a velvet to sandpaper feel. They are slightly smaller than these hairs and live in between them, they do not move much and the viewing area on the scope is very small. Finding a single one on a leaf is like the metaphorical needle in a haystack, an infestation is more obvious (if one plant is infested all others in the area should be treated as a precaution).

Q* · 04-22-2015, 10:09 PM

Thanks Brent, my plants look exactly like yours(the before pictures) i guess i have to look for some type of mite pesticide. Thanks again for posting the pictures!

**AscPete** · 04-23-2015, 10:54 AM

Brent,
IMO, some of your pictures are more indicative of Rust infection. Its possible the plants have FMV, but some of the blotching and "Brown" spots may be due to Rust inoculation of the leaves.

Leaves with Visible Fig Mosaic and Rust. Rust spread was halted with applications of Copper fungicide.

Leaves with visible Rust symptoms (thick and thin leaf cultivars) including mosaic of a thin leaf cultivar. Rust spread was halted with applications of Copper fungicide.

Visible Fig Mosaic symptoms at UC Davis.
http://ucce.ucdavis.edu/files/datastore/391-303.pdf

Rust inoculation of young leaves

It would help diagnosis if there were pictures of the underside of the leaves, if there are tan to brown discolorations just below the mosaic areas, the probability of Rust as the cause increases.

**hoosierbanana** · 04-23-2015, 03:16 PM

Pete, copper hydroxide failed to clear these symptoms earlier in the season. The miticides did clear them on every single affected plant. I have none of these symptoms so far this season and never saw them prior to 2 seasons ago.

Another name for the Fig Mite is the Fig Rust Mite, they cause superficial browning of the leaf hairs that vaguely resembles rust. The small dark brown spots on the leaves above are rust and will form spores on the underside of the leaf that can be seen with the naked eye, the larger pale spots do not form spores.

I did an informal experiment (just for my peace of mind) on a plant with rust late last season, rubbing an infected leaf with spores showing onto a small expanding leaf, it did show a small amount of deformity but I attributed that to mechanical damage, no spots resembling the ones I showed above ever formed. I did not mention it because I thought the pics of "the cure" I showed were compelling enough.

I posted some pics 2 years ago in your thread titled "In Defense of FMV Infection" which showed the underside and agreed with you that these symptoms were caused by rust at the time, similarly to the pics you showed the spots were not as bad as they were on the top of the leaf. As I recall you did not scope for Fig Mites, and with them being microscopic you could not have known if they were causing symptoms or not. I also suggested that your symptoms could have subsided due to cool temperatures reducing the mite population, your experiment was at the end of the season...

In any case, rust will not destroy the health of an entire collection, Fig Mites will. The quicker they are eradicated the better, looking back I wish I had been more skeptical and bought my handheld microscope much sooner. If you see these symptoms again I suggest you try a miticide.

**hoosierbanana** · 04-23-2015, 05:25 PM

The only study on the interaction between the fig mite and FMV and their separate symptoms was done over 50 years ago. No pics were shown of fig mite symptoms in that study, they were vaguely described as leaf distortion, slight chlorosis and russetting.The pics they do show of FMV (presumably without the mite present) do not show the spotting symptoms at all.
No other study on FMV that I have seen has removed fig mites as a variable to determine FMV symptoms alone.

http://ucanr.edu/repositoryfiles/ca1101p12-66858.pdf

**AscPete** · 04-23-2015, 05:48 PM

Brent,
The Bonide Copper Fungicide is Copper Octanoate (Copper Soap). I did not use a mitecide, Neem oil or broad spectrum insecticide during my initial observations. The conclusion at the time was that controlling Rust and providing better plant nutrition was more important than the concern of Viral infection of the trees.

Visible FMD symptomatic tree (deformed leaves and leaf mosaic) with increased cultural care and Rust treatment schedule.

Fig Mites and Rust mites are different species, there are over 1,800 different Eriophyid mite species, http://extension.usu.edu/files/publi...-mites2010.pdf . The Aceria Fici (Fig Mite) is the only species that is credited with spreading Fig Mosaic Virus. Rust mite cause surface discoloration that is usually only on the underside of leaves.

In my observations Rust will not usually cause deformed leaves but will cause leaf mosaic symptoms if the leaf is inoculated early in its growth and the relative humidity is decreased slowing the actual rust progression and development of fruiting bodies. I've not observed any infestation of Eriophyid mites in the past, but as you know I was not looking for them. What I did see and document was the fruiting bodies that are typical of Fig Rust and their locations directly under the pale mosaic spots on the leaf. On thicker and older leaves there were fewer spots, but on thin and young leaves the pale (yellow) spots were extremely visible. Another observation is that Rust will cause much more damage to Leaves and trees that are infected with FMV or weakened by stress, even with scheduled fungicidal treatment.

Rust Fruiting bodies visible on undersides of inoculated leaves.

I agree that at the first signs of trouble the leaves should be sprayed to kill mites and or rust before they spread and retard the growth of the fig trees. My current first line of defense is two (2) treatments of 70% Neem Oil @ 2 - 3 table spoons / gallon of water, with a backup (3rd treatment) of Bonide Liquid Copper(Copper Soap) @ the same concentration for rust, both are Certified Organic and can be used until harvest.
Thanks for posting your observations and adding to the discussion.

**figherder** · 04-23-2015, 05:55 PM

Great thread. Thank you for all the information.

**hoosierbanana** · 04-23-2015, 06:44 PM

Pete, the same mite has been called several names, searching for the various synonyms brings up results:

"Fig blister mite (Aceria ficus) – colourless to white, blister mites attack inside the fruit leaving rust coloured dry patches that affect eating quality. You won’t know they are there till you harvest the first fruits. If you find damaged fruit, destroy it to prevent subsequent fruits being infected as they ripen."

**AscPete** · 04-23-2015, 06:47 PM

In Brent's attached document, http://ucanr.edu/repositoryfiles/ca1101p12-66858.pdf

These tests demonstrated satisfactorily that the mosaic-like symptoms on figs did not result entirely from the toxic effect of mite feeding.

It mentions the results of feeding, it doesn't show those results, but I think that it would be similar to spider mites feeding. The included table also shows that even at one (1) infected mite per plant 7 out of 10 plants exhibit Mosaic symptoms within 90 days, pointing to systemic viral infection.

In the document, http://journals.tubitak.gov.tr/agric...-6-0807-20.pdf in the OP
The photos clearly depict viral mosaic symptoms and Necrosis (Leaf and fig) which is often an indicator of infection, but has no info on damage caused by mites feeding

**hoosierbanana** · 04-23-2015, 06:48 PM

These names are not preferred but have been used in the past.

**hoosierbanana** · 04-24-2015, 02:01 AM

Here are some descriptions and pics of "chlorosis and distortion" caused by fig mites which I found searching for the name Eriophyes ficus. I had searched all the other common names previously but had not tried this Latin synonym.

Moraceae Ficus carica L. Fig Mosaic virus disease caused by Eriophyes ficus Cotte (pi. 74) No proof was provided until 1955 that Eriophyesficus was the vector of a virus causing fig mosaic. This mite proved to be an efficient vector. In addition to transmitting this virus, it causes leaf distortion, chlorosis, russeting, and scarring of the eye scales and seeds of the fruit. It occasionally causes stunting of twigs and premature leaf drop. Eriophyesficus is a yellowish, slender, spindle-shaped mite; the female measures 160-202 microns long and the male about 140 microns. The featherclaws are five-rayed; the dorsal shield is marked with longitudinal ridges, the lateral ones forming closed cells anterior to the setal bases; the hysterosoma is covered with elliptical microtubercles; and the coverflap of the female genitalia has eight ribs. All stages and both sexes of the mites are found on the leaves, in the buds and fruit, and occasionally on the stems throughout the year. Eggs are laid in the buds, on branches, and on both surfaces of the leaves following bud burst in the spring. During July many mites move off the leaves to enter the fruit, where they lay eggs among the eye scales, and all stages are found inside the fruit. The mites overwinter in the buds. Fig mosaic virus has been reported from fig. The vector, E. ficus, is widespread on this plant in California; it also occurs in Oregon, Italy, and India. It is likely that both virus and mite will be found in most areas where figs are grown. References: Baker, 1939: 266; Cotte, 1920: 26; Keifer, 1938b: 303; Oldfield, 1970: 361. PLATE 74.-^4, B, Fig leaves, showing distortion and chlorosis; C, Eriophyesficus Cotte.

**AscPete** · 04-25-2015, 10:03 AM

An important finding that was overlooked in one of the posted documents, for those of us also growing Mulberry trees...

http://www.google.com/url?sa=t&rct=j...91665533,d.cWc

Fig mosaic disease (FMD) was first described in 1933 from California (Condit and Horne, 1933) and it was suspected that the eriophyid mite Aceria ficus (Cotte) might transmit the causal agent due to its widespread occurrence on figs in that region. Although this fig mite was considered the probable vector of FMD, no evidence was provided until 1955 (Flock and Wallace, 1955). These authors observed that feeding injury by A.ficus might cause early symptoms that could be confused with a virus infection. To differentiate between the two disorders, eggs from a virus-free colony were transferred to one group of healthy seedlings and infective eriophyid mites to another group. Virus-free mites caused leaf distortion, chlorosis and russetting which were distinguishable from fig mosaic symptoms that appeared on plants fed on by the infective mites (Oldfield, 1970). This experiment showed that the FM agent(s) was not transmitted through the egg of A. ficus. Flock and Wallace (1955) demonstrated that mosaic symptoms persisted on figs in the absence of A. ficus by treating infested cuttings with sulphur to kill the mites. Since all stages and both sexes of this mite were found throughout the year (Baker, 1939), it has the potential for vectoring the FM agent(s) rapidly in the field. FMD has been reported only from species of the family Moraceae up to now. The host range of the FMD agent includes different Ficus species as reported by Condit and Horne (1933) and Burnett (1962), who also showed Ficus diversifolia Blume and Cudranea tricuspidata to be a reliable indicator plants for FMD. Vashisth and Nagaich (1965) showed that it also infects mulberry (Morus indica).

**dobemom** · 07-01-2015, 07:26 PM

Thanks to everyone for sharing their research and results. I haven't run into these problems yet (and hope not to! ) but now I know what I should be looking for in the future. You guys are the BEST!!!

**rusty hooks** · 07-02-2015, 01:09 PM

Thanks for that last Pete...I'm running out to check the fruitless mulberry just upwind from my shade structure.....Grrrr

**AscPete** · 07-11-2015, 01:54 PM

There has been a couple of discussions recently on the forum about FMV, Leaf Mosaic and Fig necrotic spots.

http://www.ourfigs.com/forum/figs-ho...infected-fruit

FMV Mites - Ourfigs.com

http://www.ourfigs.com/forum/figs-home/26952-fmv-mites

Being tis my first season having many new fig varieties other than Bi39 and Blanco by my home never seeing FMV/Mites before I assume it came from someone else

http://www.ourfigs.com/forum/figs-ho...uit-and-leaves

All the documented evidence since 1955 and current DNA testing concludes that...
Fig Mites can and do transmit FMV from infected to uninfected trees.
Fig Mites feeding causes russetting, leaf spots and localized damage.
FMV is not transmitted through mite eggs.
Fig mosaic virus infects the fig trees.
Cloning and grafting infected plant material will produce infected trees.
Fig leaf mosaic, leaf and fig necrotic spot are often symptoms of FMV infection(s).

http://www.researchgate.net/profile/...1ccd000000.pdf

Fig mosaic disease (FMD) was first described in 1933 from California (Condit and Horne, 1933) and it was suspected that the eriophyid mite Aceria ficus (Cotte) might transmit the causal agent due to its widespread occurrence on figs in that region. Although this fig mite was considered the probable vector of FMD, no evidence was provided until 1955 (Flock and Wallace, 1955). These authors observed that feeding injury by A. ficus might cause early symptoms that could be confused with a virus infection. To differentiate between the two disorders, eggs from a virus-free colony were transferred to one group of healthy seedlings and infective eriophyid mites to another group. Virus-free mites caused leaf distortion, chlorosis and russetting which were distinguishable from fig mosaic symptoms that appeared on plants fed on by the infective mites (Oldfield, 1970). This experiment showed that the FM agent(s) was not transmitted through the egg of A. ficus. Flock and Wallace (1955) demonstrated that mosaic symptoms persisted on figs in the absence of A. ficus by treating infested cuttings with sulphur to kill the mites. Since all stages and both sexes of this mite were found throughout the year (Baker, 1939), it has the potential for vectoring the FM agent(s) rapidly in the field.

Symptomatological observations of inoculated plants; All fig seedlings and three C. roseus seedlings out of five exposed to eriophyide mites showed mosaic, vein clearing and small yellowish spots after 10 days and 6 weeks, respectively (Fig. 1B and C). When symptomatic periwinkle shoots were grafted onto healthy periwinkles by chip-budding, similar symptoms appeared within two months, demonstrating that the symptoms were due to virus infection rather than to damage from mite feeding. No symptoms were observed in other test or control plants for one year. Similar transmission experiments from fig to periwinkle using viruliferous A. ficus had been done by Credi (1998) who reported the appearance of virus-like symptoms on a periwinkle plant after an incubation period of 40 days. This plant showed chlorotic spotting, mosaic and yellowing of the leaves and malformation of the laminae. It has already been reported that FMD is transmissible by A. ficus from infected to FMD-free fig seedlings (Proesler, 1969, 1972; Çaglayan et al., 2009) so that our data confirm its transmission from fig to periwinkle

http://www.ipm.ucdavis.edu/PMG/r261100611.html ,

MANAGEMENT; For tree propagation material, choose trees that do not show symptoms of mosaic. Examine propagated young plants carefully for symptoms of mosaic before planting them in the field. Never plant fig cultivars that are propagated from mosaic-infected trees. Controlling fig mites may help reduce incidence of this disease. FMD can be transmitted by vegetative propagation material and an eriophyd mite, A. ficus (Flock and Wallace, 1955), but not by seeds (Martelli et al., 1993).

**cis4elk** · 07-13-2015, 01:16 PM

This may have been covered, but if so I didn't see it. At least all together in one spot.
There is a difference in the occurance of leaf splotching. There is the blatant leaf discoloration, splotchiness, and disfiguration which occurs from the moment of leaf formation and will be there for the life of that leaf. This is FMV, straight forward.
Then there is the other thing, which occurs on leaves which can be fully formed, deep green, and healthy one day and then start developing splotches along with the younger leaves the next. To me, I could be wrong here but I don't think so, this is not FMV but something entirely different. Maybe rust or some other form of fungus.
I think it sounds like Fabio and I have the same thing going on. I have one section of trees(about 15) which 3 weeks ago had flawless leaves(all but one which I know shows mild FMV annually) and now all but 2 have at least some light colored splotching. Similar to Fabio, we also have had abnormal amounts of rain this year. One more addition, the 2 trees that are still showing no splotching, I know for sure one of them has some FMV because it displayed it in it's first year after rooting. These 2 "clean" appearing trees are on the end of the row which are the most out in the clear and get the best air circulation.
Given our normally dry air here, fungus is not a problem. I have recieved trees in the mail over the years with these same splotches on the leaves which either dropped or stayed as is and never developed further. So the spores are there, just waiting for the right time. A few of the splotches have a dark necrotic spot, but 98% are just a lighter colored splotch with no visible sign of anything different on the under-side of the leaf.

Fig Mosaic Virus (FMV) Prevention and Control

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