White hairlike fuzz (it's not mealybugs) on den canes

[KatieM]

Hey, guys! I have lurked for so long on here and decided it's time to post! My Den Smillae is getting these white hairs. I've actually seen it before on some of my vegetables as well (none present currently anywhere but here). This was originally potted in a bark mix and the leaves fell off so I put it in a live Moss which I have found has really helped keep fungus at bay. I know it's getting ready for hibernation time but they didn't fall off in a way like they usually do. Is this fuzzy stuff a fungus possibly? Everything I looked at shows a more powdery substance but I'm not finding anything that shows these more hair like types. Any ideas on what it is so I can figure out how to treat it would be great! It's been outdoors in the sun getting plenty of light hasn't been too damp and I'm in Northeast Florida. I literally just received my first ever bottle of physan today so thinking may be worth spraying that but would like to know what I'm fighting first.

[Ray]

Fungal breakdown of dead tissue.

[KatieM]

Originally Posted by Ray

Fungal breakdown of dead tissue.

Thanks, Ray! Do you think Physan would help with this? Clean out everything and treat, maybe regularly to be preventative? Any other treatments you'd recommend?

[ebrookmi]

Is there any green tissue beneath the papery sheaths on the canes? Your plant's canes look pretty brown and shriveled... fungus grows on dead material. How are the roots?

[estación seca]

Welcome to the Orchid Board!

That's my question too... I wonder whether it's still alive. This is normally a very easy to grow plant if you have warm and humid conditions, like your Spring-Summer-Fall. It is not supposed to drop leaves. Any chance you let it dry out in the bark for extended periods of time? How long ago did you move it to sphagnum? How wet have you kept the sphagnum? If the sphagnum were too wet for too long it could have suffocated the roots.

This kind of fungus lives on dead organic material and doesn't damage living material, so spraying is pointless. I only would use a fungicide if I were certain a fungus were causing the problem, I knew which fungus it were, and I knew the fungicide were effective against that fungus.

[KatieM]

Originally Posted by estación seca

Welcome to the Orchid Board!

That's my question too... I wonder whether it's still alive. This is normally a very easy to grow plant if you have warm and humid conditions, like your Spring-Summer-Fall. It is not supposed to drop leaves. Any chance you let it dry out in the bark for extended periods of time? How long ago did you move it to sphagnum? How wet have you kept the sphagnum? If the sphagnum were too wet for too long it could have suffocated the roots.

This kind of fungus lives on dead organic material and doesn't damage living material, so spraying is pointless. I only would use a fungicide if I were certain a fungus were causing the problem, I knew which fungus it were, and I knew the fungicide were effective against that fungus.

Thank you for this! It wasn't super healthy when I received it last month. I watered it twice a week when it was in the bark, popped in in the live moss about a week ago and mist it only enough to keep the moss alive (usually once a week), but this lovely fungus was present prior to putting it in the moss. I had done peroxide on it and cleaned it but it decided to come back. Suprisingly roots are ok, not great, some mushies that I will trim and peroxide, but some healthy too. Do you think it's worth peeling some of the brown papery parts off the canes and seeing what is going on underneath? Or maybe it is a lost cause, which is a bummer because I've been so excited about this one, but definitly don't need it infected the rest of my pretties. So this Den keeps its leaves? Good to know.
Phals, I've got, Dens I am still piecing together which are deciduous, semi, etc. Great to know about the fungicide. I have always been an "organic" grower, well except for rubbing alchohol when needed and peroxide, so chemicals are all new to me and would still prefer to only use when necessary.

---------- Post added at 04:25 PM ---------- Previous post was at 04:24 PM ----------

Originally Posted by ebrookmi

Is there any green tissue beneath the papery sheaths on the canes? Your plant's canes look pretty brown and shriveled... fungus grows on dead material. How are the roots?

Some decent roots and some green under the paper on some canes.

[dbarron]

Where I've seen this is only in dying or dead tissue and in cold dark environs. Take that for what it's worth.

[Roberta]

My Den. simlliae gets watered year around. Leaves eventually drop on older canes - year old or older, that's where the flowers come from (bare canes). But it's a warm, tropical type that does not want a winter rest based on what I can see on mine. The pseudobulbs with the white fungus look pretty dead, the canes on the right of the photos look fine. What is the condition of the roots?

[KatieM]

Miss, Roberta. Thank you for this info! That is different than what I've read. I love first hand knowledge like this! Den's are all so different so it's hard to know just by reading some article. This is much better. I separated the dead canes, cleaned the good canes up and repotted it and it's already much happier. Sprayed a little peroxide but as y'all suggested I did not spray the physan. If it stays happy and gets some new growth I'll post an update. Thank you again, everyone!

[Roberta]

No more peroxide! It can damage roots, especially the new growing ones! If you fix the problems of the medium so that the roots get air, you'll solve the fungal problems without chemicals. (If you have to choose between Physan and peroxide, chose Physan... it may not do much but it's pretty harmless, where peroxide can be very harmful if it gets on roots)

For sure, there are huge differences with different types of Dendrobiums. But that's to be expected - it is a huge genus, Habitats go from humid tropical rainforests to the foothills of the Himalayas and everthing in between so different species have very different needs within the genus. There are different sections within the genus that helps. (To get info about those groupings, do take a look at IOSPE You'll also get a summery of habitat information.

Here is the blurb on Den smilliae
IOSPE PHOTOS

It suggests a "slight" winter rest. I'd hold back on fertilizer, but not water... you water everything less in winter because things don't dry out as fast. (Unless, of course, your growing conditions are hot and super humid like they are in Papua New Guinea lowlands... which they probably aren't)