# what's this ****?



## ronan (Jul 17, 2012)

something very bad...but what? i trashed a lot of phal...
thx for helping.


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## eggshells (Jul 17, 2012)

Looks like fungal or bacteria. I saw those black rings before is it called pseudomonas?


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## SlipperKing (Jul 17, 2012)

Fungus on a Phal.


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## SlipperFan (Jul 17, 2012)

Looks to me like somebody's been chewing on it.


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## Roth (Jul 18, 2012)

rhizoctonia confirmed... I got that one several times on import, it is not so rare on Asian monopods, and usually shows up on a fresh import. It is indeed very contagious in a nursery, usually targeting soft phal leaves, sometimes new paph leaves, but usually it caters to phals and monopodials.

Against that, only ONE fungicide is efficient, tolclofos methyl. There is none other... 

Terraclor/Quintozene is efficient as a preventative, but tolclofos methyl/RIZOLEX saved for me plants that were far more infected than ronan photo...


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## Ozpaph (Jul 18, 2012)

Quarantine and cinammon till you get the right fungicide.


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## NYEric (Jul 18, 2012)

Good luck.


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## Ray (Jul 18, 2012)

Actually, Zero-Tol and Oxidate are listed for use as a topical treatment for rhizoctonia.


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## Stone (Jul 18, 2012)

I thought rhizoctonia was a group of soil-bourne fungi which attack roots etc?


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## Roth (Jul 18, 2012)

Stone said:


> I thought rhizoctonia was a group of soil-bourne fungi which attack roots etc?



Have a look in images.google.com for 'rhizoctonia foliar blight'. Hark Orchideen has one picture too, the first one, of rhizoctonia crown rot, which looks similar too, though the symptoms are way less extensive when the humidity is low, or for some specific plants.

Zero tol is not going to help once the infection is there, as the filaments and spores travel everywhere, and are very robust... It can be a preventative however. Only tolclofos methyl can control this on already infected plants. The problem being that the plants can be asymptomatic for months or even a couple of years. In this respect it resemble the equally severe problem of fusarium, but the symptoms are different. I suspect many plants that suddenly 'do not grow well' or 'stop their growth and slowly die' are affected by latent infection of fusarium or rhizoctonia, that progress slowly by steps.


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## SlipperFan (Jul 19, 2012)

Doesn't look the same to me. I still say it looks like, when the leaf was still young and folded, something chewed on it.


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## Russ1992 (Nov 23, 2022)

Roth said:


> Have a look in images.google.com for 'rhizoctonia foliar blight'. Hark Orchideen has one picture too, the first one, of rhizoctonia crown rot, which looks similar too, though the symptoms are way less extensive when the humidity is low, or for some specific plants.
> 
> Zero tol is not going to help once the infection is there, as the filaments and spores travel everywhere, and are very robust... It can be a preventative however. Only tolclofos methyl can control this on already infected plants. The problem being that the plants can be asymptomatic for months or even a couple of years. In this respect it resemble the equally severe problem of fusarium, but the symptoms are different. I suspect many plants that suddenly 'do not grow well' or 'stop their growth and slowly die' are affected by latent infection of fusarium or rhizoctonia, that progress slowly by steps.


Have you tried other fungicides for Rhizoctonia like:

Cleary 3336
Thiomyl
Zyban

It doesn’t look like Rizolex is approved for orchids/ornamentals


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