symptoms of Fusarium wilt

[MrsSky]

I just found fusarium wilt (the bright purple ring) on 2 dendrobiums (a den labeled Airy Gold and Den. Pixie Princess). I am reading other entries on fusarium wilt and I would like to make sure that this is contained before it hits the rest of my plants. I frequently treat with Physan 20 so I am surprised by this. I want to make sure that I pull any suspect plants. If I understand, I should look for plants that are not thriving, with thin leaves and psuedobulbs or plants with blacking on the base of the psuedobulbs? If I have a suspect plant is the only real way to tell is to cut into the area for the purple band ring? And then to cut until there is no ring (using disposable razors for each cut).

I am worried about my Dendrobium antennatum. I recently repotted it and I'm not sure if it is sulking or if it has fw. I also have several healthy looking on oncidium hybrids that have a black on their psuedobulbs. Since they are not soft, I always assumed that it was an ok discoloration.

Any help appreciated.

[WhiteRabbit]

I've had a couple orchids with fusarium wilt. The most recent didn't show symptoms - tho perhaps that would have appeared before much longer.

So, like you, I am now concerned with any orchid that isn't doing as well as I think it should

I hope some other members can chime in, and help us out!

[nikkik]

I had recently found fusarium in a few of my orchids. I bought a Vanda Robert's Delight in February it looked robust and healthy, the roots were great! Then a few weeks later a few roots started to yellow and I thought it was sulking a bit. Long story short I started to have my doubts and when I cut, I had my purple ring! Sadly, I did not get a clean cut and I no longer have "Robert".

We also have 4 vandas that came from the raffle table at my orchid society. Three had fusarium and we discovered it because we could see the purple banding above some of the roots. Luckily, the fusarium didn't move too far and we were able to get clean cuts. We sprayed the plants and cauterized the areas we cut.


In my experience, if you examine the plant well, sometimes, you can see the fusarium without having to hack it up first.

Good luck to you, I hope you dendrobium is fine.

[MrsSky]

Thank you for the info on fusarium. I have only had time to check my den spectablile and it was fine. I cut off two shriveled unleafed canes to check and then dusted with cinnamon. I have not had time to check my other dens yet. I had some brown rot from leaving my oncidium hybrids out at night to attend to first.
I was very relieved that my large spectabile was fine but it does have a bit of leaf spot on it from our unseasonably cool/wet weather (which I doused with neem oil). I should be more careful with it.
Finding the fusarium ring has cautioned me to be more vigilant about sick plants. I should have noticed the decline in the Den Airy Gold. Since I house and water the dens together I guess it passed to the Pixie Princess. I will have to buy another it is a cute plant.

[MrsSky]

I just checked Den. Kalapana Blushing and it only had a bit of rot (due to cold rain) on a keiki which I sliced off. I'll check the rest later.
Theoretically, does it matter if I'm checking old canes or even keikis? I mean the infection could be isolated in another part of the plant.
On the last picture it is easy to see the spindly cane I was going to take off my dendrobium antennatum to check but since I keep them isolated I'm not in a hurry to hack at it since I just repotted it into a tree fern pot. I did check my Den Spectabile because it is such a nice sized plant, I wanted to try to save part of it if it was sick. I don't have many dendrobiums and I am learning mostly through error and the occasional flower spike.