Snow white fungus infection

[Merita]

About 3 years ago I transplanted this plant and it was active, it bloomed normally but this year I noticed that it only had a single new growth and the roots in one part and coming out of the pot, it did not look healthy and I decided to take it out of the pot. What you see was what I found, already in other small pots I had seen it as a spider web. This fungus suffocates the roots until it ends up killing the plant. I washed the plant well, the entire back part was almost without roots and with the dry buds, I cut it and left the healthy part, put a fungicide and planted it in another pot. What else can I do?

[estación seca]

Looks like decomposing bark. White fungus typically is a saprophyte, meaning it only grows on dead organic matter. You are correct that it may grow so vigorously it chokes out the roots of orchids it does not attack. This means in your conditions bark only lasts two years, and you must repot after that, even if the plant has not outgrown the pot.

You might consider using an inorganic potting medium, like LECA, large pumice or volcanic cinders. I don't think pumice is readily available in Florida, being so far from volcanoes, but cinders may be available as landscaping material. If they are too big you can break them with a hammer.

For now use the garden hose to spray off as much old medium as possible. Let the plant sit in shade until you have your new potting material and repot.

[Merita]

Originally Posted by estación seca

Looks like decomposing bark. White fungus typically is a saprophyte, meaning it only grows on dead organic matter. You are correct that it may grow so vigorously it chokes out the roots of orchids it does not attack. This means in your conditions bark only lasts two years, and you must repot after that, even if the plant has not outgrown the pot.

You might consider using an inorganic potting medium, like LECA, large pumice or volcanic cinders. I don't think pumice is readily available in Florida, being so far from volcanoes, but cinders may be available as landscaping material. If they are too big you can break them with a hammer.

For now use the garden hose to spray off as much old medium as possible. Let the plant sit in shade until you have your new potting material and repot.

Thank you, I have already planted in volcanic rock and they don't prosper, the heat here is great, it only cools down in winter and my plants are outside, in the trees. I have transplanted plants with the substrate completely dusted and this has never happened to me. The substrate that I threw away was not nearly decomposed and the fungus covered everything. In other pots that have been planted for a year, I am also seeing that the fungus begins, could it be that I put slow-release fertilizer about a year ago?

[estación seca]

It's difficult to say what it is. Ask other orchid growers in your area whether they've had it. I do wonder about the slow-release fertilizer.

[Roberta]

Another thought... do you use a snail bait such as Sluggo? When it gets wet it looks like a fungus (sort of like a white goop) but isn't, of course.

[Merita]

Originally Posted by Roberta

Another thought... do you use a snail bait such as Sluggo? When it gets wet it looks like a fungus (sort of like a white goop) but isn't, of course.

No, I haven't had snails yet, I think with the thrips, squirrels, other bugs, the current heat, and this fungus now, I'm more stressed than the plants. Thanks Roberta, despite everything, I enjoy this hobby.