Fusarium wilt

[IvoPhal]

Need some advice how to fight with fusarium oxysporum.
I have 2 phals with fusarium. I isolate them, they were planted with some modern sustrate special for orchids "Columni" based on zeolite. The phals were doing very well new buds, flowers etc. Than I noiced wilt, of course immediatly I started to repot them and surpsrise: just a few roots on each plant and the famous velevet ring. So, the treatment: 10 min soaking in Physan, than 10 min in Thiophanate-methy fungicide (Thymol in US) I think and than potted in a classic orchid mix - bark, charcoal and perlite.
According to AOS table I'm palning to treat with: azoxystrobin, captane and Cyprodinil, Fludioxonil ( fungicide Switch in Europe).
And to keep the substrate on the dry side, no ferilzers etc.
According to advice in found in the net; 1 gr. fungicide diluted wih 1 liter water. Spraying.
Could you, pls, share your experience how to treat fuzarium?
Thank you!

 

[Ray]

Fusarium is relatively rare in home-grown plants. The so-called “velvet ring” might be nothing more than mold that is unrelated.

Please describe the care, repotting, etc. that plants have been getting and post photos so we can help.

 

[IvoPhal]

 

[IvoPhal]

They was planted in columnni substrate, low humidity in the summer, fertiliser from growth technology, named Focus - specially for orchids, foliar spray. In the winter I used led lamps and orchids developed very well and suddenly this wilt, the red color is from fungicide cyprodanyl, applied locally.

 

[Ray]

Without a yellowish tinge to the leaves, that is not fusarium, it is straight up desiccation. I just hope your extreme treatments haven't rendered the root system ineffective. Ideally, you want to keep the potting medium moist at all times.

See if you can get some Kelpak (I know it's available in EU). Mix up a 1% solution and immerse the entire (unpotted) plant in the solution for about an hour, then pot it up, watering it in with that same solution, and invert a clear plastic bag over the plant and pot to trap humidity and slow the drying of the potting medium. Keep it warm and shady, and in a few weeks you should see new roots emerge.

 

[Duck Slipper]

I agree with Ray, DRY. Perhaps roots are in poor condition and can't take up the needed water to look hydrated.

 

[IvoPhal]

Thank you for diagnosis! Could I ask you, pls, for the remedy?
I have a lot of seaweed, velokelp, apathus rootbouster and so one useful for my bonsai collection after repotting…

 

[IvoPhal]

O, I just noticed that you give me the answer, thank you very much indeed, so kind of you and sorry not to read your entire post.

 

[NYEric]

Too dry.

 

[IvoPhal]

columni substrate I like experimenting with different media. Like I mentioned the producer of the substrate recommended minimum watering. But indeed when I repotted the phals they were, the roots soggy, so I suppose is too much water and then root rotting and wilted leaves.

 

[IvoPhal]

Yep, it was fusarium wilt, unfortunately the kelp and high humidity did not help. I have some new roots with together with yellowing leaves and velvet rings.
Anyway I learned my lesson the other orchids from the small collection are fine