Mycoplasmosis

Use this section to discuss matters relating to any and all issues involving horticultural pest and disease management. This is where one posts unknown pest/damage photos for ID help.
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bigdaddyscondition
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Mycoplasmosis

#1

Post by bigdaddyscondition »

A problem that is new for me is a reticular scar-like disfigurement of one of my echeverias, the (I think) Dick Wright hybrid known as 'Pappy's Rose.' Just by luck I happened across a YouTube video interview of this master echeveria hybrid creator, and it seems from the video I may be dealing with a mycoplasma infection. Dick says the treatment is systemic streptomycin (Agromycin). This is an aminoglycoside antibiotic that was used in human medicine decades ago but was too nephrotoxic and vestibulotoxic.

Anyway, I'm just starting to look into this problem with my echeveria. In the meantime, does anyone have any knowledge of this? Here are 3 pics of the reticular pattern on the leaves of Echeveria 'Pappy's Rose'.
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Stone Jaguar
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Re: Mycoplasmosis

#2

Post by Stone Jaguar »

Perhaps, Gee can cut and splice this into a new thread on suspected mycoplasmosis in succulents? Thanks very much for posting these images and your thoughts on how to control this infection.

I have worked with Agrimycin quite a bit in the past and have published a treatment protocol based on it for suppression of aroid blight (Xanthomonas axonopodis/"campestris" pv. dieffenbachiae) in cultivated aroids. It is an excellent product for use on a number of ornamentals (esp. aroids & orchids), but requires multiple applications at ~five day intervals to work as advertised. Believe it or not, the USDA OKs (or did) use of this product for organic-labelled crops.

US formulations lack the tetracycline add-on available in LatAm that makes it so effective for bacterial (esp. mycoplasmas) control. I jury-rig my own combos here (not an endorsement or reco, just an observation) that also include turmeric tea and a touch of bicarbonate of soda when the fires are raging. There is a great deal of information on this product available online, including peer-reviewed studies by Asian researchers on synergies when used with other compounds. Please be aware that even at reco'd dilutions it can burn the crap out of some sensitive leaves across a wide range of plant families. It definitely has a real shelf life, so most home gamers will probably find it hard to justify buying a kilo of it just to use a fraction and then have to toss it out ~two years later.
bigdaddyscondition
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Re: Mycoplasmosis

#3

Post by bigdaddyscondition »

Here's some follow-up on how the plants pictured above fared. They continued their downward spiral despite several drench treatments of Agri-Mycin solution that I compounded per directions on the label. They developed all the signs of the infection, including yellow discoloration and stunting and deformity of leaves. I eventually dug them and their soil up, bagged them, and discarded them.

I also took a few of the smaller plants showing the reticular pattern and heat treated them according to instructions from Kraig Wright at Wright Nursery. Using a candy thermometer I immersed them in a water bath at 105 degrees F. for 30 minutes. I then repotted them in the mix recommended by Dick Wright: 6 parts pumice, 2 parts potting mix, and 2 parts washed builder's sand. These heat treated plants never thrived. They soon developed yellow discoloration and stunting of leaves, and it was apparent they still had the disease. I threw them all away.

I did more reading and also consulted my county agriculture extension. This disease is well known to horticulturists as aster yellows. The pathogen is now called phytoplasma, and the consensus is that no available antimicrobials are effective in treating it.

At this point I'm potting some apparently clean new rosettes I'm growing from a beheaded E. 'Pappy's Rose'. So far they appear free of disease.
dontwaterme
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Re: Mycoplasmosis

#4

Post by dontwaterme »

I have a ruffled echeveria that I believe may be infected with mycoplasma. I've already isolated the plant and I'm pretty much ready to toss it but I'm still unsure if this is truly mycoplasma at work since the scale/scare typical of this infection is only seen on the stem. The leafs do look a little blotchy but this plant receives partial sun/rain.

I'm leaning towards tossing it and isolating other plants that were nearby just to be on the safe side. Any input would be greatly appreciated.

Typical scale/scare pattern of mycoplasma present on stem
Typical scale/scare pattern of mycoplasma present on stem
Typical scale/scare pattern of mycoplasma present on stem
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Gee.S
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Re: Mycoplasmosis

#5

Post by Gee.S »

Please, no sideways pics...
Agave
"American aloe plant," 1797, from Greek Agaue, proper name in mythology (mother of Pentheus), from agauos "noble," perhaps from agasthai "wonder at".

"Some talk the talk, others walk the walk, but I stalk the stalk"
bigdaddyscondition
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Re: Mycoplasmosis

#6

Post by bigdaddyscondition »

dontwaterme, your echeveria's leaf lesions don't look like the typical stigmata of phytoplasma (formerly called mycoplasma) infection. The stem is not very clear to me in your photo, but if your plant shows any sign of the infection, you should see it in the leaves. I wouldn't discard the plant just yet, unless you can easily replace it. The disease should declare itself with the typical reticular leaf lesions if it's infected.

Here's some follow-up on the plants whose treatments I described above. Back in June 2018 I had saved some new rosettes obtained from some beheaded E. 'Pappy's Rose' plants. These rosettes appeared healthy, and I planted them. They did fine for months, then suddenly started getting the deformed and scarred leaves. I dug them up and discarded all remaining specimens of this echeveria.

Looking back, I wonder if this particular cultivar is especially susceptible to phytoplasma infection. That may be why it's no longer available for sale. Also, Dick Wright now seems to have come around to the consensus that no treatment works once an echeveria is infected, and discarding it is the only real course of action. The streptomycin, heat treatment and replanting, all of it...pretty much worthless for treating phytoplasma infection in echeverias.
dontwaterme
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Re: Mycoplasmosis

#7

Post by dontwaterme »

bigdaddyscondition wrote:dontwaterme, your echeveria's leaf lesions don't look like the typical stigmata of phytoplasma (formerly called mycoplasma) infection. The stem is not very clear to me in your photo, but if your plant shows any sign of the infection, you should see it in the leaves. I wouldn't discard the plant just yet, unless you can easily replace it. The disease should declare itself with the typical reticular leaf lesions if it's infected.

Here's some follow-up on the plants whose treatments I described above. Back in June 2018 I had saved some new rosettes obtained from some beheaded E. 'Pappy's Rose' plants. These rosettes appeared healthy, and I planted them. They did fine for months, then suddenly started getting the deformed and scarred leaves. I dug them up and discarded all remaining specimens of this echeveria.

Looking back, I wonder if this particular cultivar is especially susceptible to phytoplasma infection. That may be why it's no longer available for sale. Also, Dick Wright now seems to have come around to the consensus that no treatment works once an echeveria is infected, and discarding it is the only real course of action. The streptomycin, heat treatment and replanting, all of it...pretty much worthless for treating phytoplasma infection in echeverias.
Thanks for the thorough reply and update on your treatments. Knowing that the scar pattern should be evident on the leaves, I'll hold onto this plant and monitor it while it's isolated.

I've tried to upload a cleared photo of the stem just so you can get a good look at what I was referencing.
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bigdaddyscondition
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Re: Mycoplasmosis

#8

Post by bigdaddyscondition »

Thanks for the closeup, I see it better now. I agree it looks suspicious, and now I see your concern. At this point, if it were my plant, I would still hold on to it. If the plant is infected, the leaves should show the characteristic lesion soon. Good luck.
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