Fusarium wilt in my shrivelled Sharry Baby?

[turock]

Hi y'all!

I am new to this forum, though I have been lurking around for some time, learning from your wisdom. I'll make a proper introduction soon, but I needed to post about a more urgent problem first.

I recently purchased a wilted Sharry Baby oncidium at an auction and, despite my best care, its pseudobulbs haven't plumped up at all. I repotted it today, and accidentally divided the plant in the process. I noticed a bit of purple ring in the division point, feared fusarium wilt, and sliced off a bit more to get a better look.

Sure enough, there are purple rings in every rhizome I cut. The plant's mature pseudobulbs are all very shriveled, but it has several healthy-looking new growths with root systems. I've attached some pictures of the purple rings in question, and the new growths from the healthiest divisions. However, I have very little experience with oncidiums, so I need some advice please!

1) Is this purple ring ALWAYS an indicator of fusarium wilt?
2) Is fusarium wilt always fatal, or can it be cured?
3) Is it possible to divide off the brand new growths and get them to survive?
4) How contagious is the disease? Could it spread to another orchid that touches the infected plant or gets water splashed on it from an infected plant?

I really appreciate your help, in advance!

[Ray]

I may be wrong about this, but your photos do not seem to display the "purple ring" that I have seen with fusarium before.

To answer your other questions, it is usually quite fatal, but biological treatments such as Inocucor Garden Solution have been known to cure other fungal infections, so it might be worth a try (assuming that's what you've got).

Fusarium is highly contagious, and water droplets or shared baths are ideal vectors.

I would not divide that plant. Not only is a weakened plant (again assuming it is) a bad choice for division, but the general rule of thumb is to keep divisions to a minimum of 2 or 3 old growths plus one new one, and your plant does not appear to be ready for that.

[turock]

Thanks, Ray, for your insight. I've never seen a healthy (or unhealthy) cut rhizome, so I didn't know what to expect.

I will keep the plant quarantined in case it is something sinister, and hope for the best.

What you are seeing in the pictures are actually divisions from the much larger mother plant. One was an accidental division and the other was one I cut off to check for the purple ring.

I've got them all potted up together, and fully expect them to take a while to recover from their stress, if they do at all. I have it in an airy pot with bark and a touch of sphag, and I water it carefully. The plant does have several new growths with healthy root systems.

Since I bought this plant at auction, I have no idea about its past care. What other problems do I need to look out for that could be causing the bulbs to shrivel so severely?

[Ray]

Oh, I see I misunderstood. If the plant has already been divided, you're better off to pot them up separately.

Shriveled pseudobulbs may occur for several reasons, the most common being under watering, or doing something (suffocating the roots with old potting medium or excessive watering) that renders the root system ineffective at taking up water. They may or may not recover, but the new growths with new routes that are tailored for the environment, should plump up just fine.

[turock]

Thanks again, Ray. This plant is devoid of all roots, except for the ones the new bulbs are throwing out, so that very well may be the source of the shriveling. Time will tell if it will recover! I sure do look forward to smelling those blooms, if it does!

On the other hand... do I really want to be craving chocolate every day it's in bloom? hmm...

[Ray]

Originally Posted by turock

On the other hand... do I really want to be craving chocolate every day it's in bloom? hmm...

it's worth it.

[ThePinkCucumber]

Originally Posted by turock

Thanks again, Ray. This plant is devoid of all roots, except for the ones the new bulbs are throwing out, so that very well may be the source of the shriveling. Time will tell if it will recover! I sure do look forward to smelling those blooms, if it does!

On the other hand... do I really want to be craving chocolate every day it's in bloom? hmm...

We bought a Sharry Baby in May, with a very, and I mean VERY poor root system. It's been only three months and the plant just been going nuts growing all these new roots and two new pbulbs. The old pbulbs are shriveled, but the one maturing growth is getting nice and fat. These plants are definitely fighters

[turock]

Ah, that's nice to know! Thanks for the encouragement.

Does anyone have a few pictures of healthy rhizome division vs. fusarium-infected divisions? Specifically on a Sharry Baby or closely related oncidium? I've seen a couple of pictures of fusarium on the St. Augustine orchid page, but don't have anything to compare them to.