Suspicious ring in cut rhizome - Fusarium Wilt?

[WhiteRabbit]

Today, I decided to tackle a repot and dividing of a No I.D. Onc. alliance inter-generic.

Leaves have (likely) fungal spots on older growth - this one does grow outside year-round, and I suspect it is too damp and cold in winter, causing the spots. Otherwise, the plant looks good! Big, green, plump, and firm pbulbs. Good looking new growth.

But after cutting the rhizome, I noticed the ring...

Last year, I had another Onc. inter-generic, going downhill with growths rotting - when I went to cut off the affected pbulbs I noticed a ring in the rhizome - tho much worse looking than the ring in this plant's rhizome. Asking here on the board, fusarium wilt was suggested as the culprit, and a link to an orchid diseases page did seem to confirm that. (That plant was trashed -that post and pix here: http://www.orchidboard.com/community...me-please.html)

This ring is not nearly as bad looking as the plant last year, and plant otherwise seems healthy (tho you can see there is root rot - I have been watering this frequently with the recent extreme heat, so that's possibly the cause, but could also be caused by fusarium) but I am afraid it may be fusarium ...

What say you all?

I don't want to waste potting media if the plant is likely to croak (I might pot one or two of the divisions to see how it goes, but trash the others).

I could cut further into the rhizome, to see if there is any free from the ring, but I took a few small divisions from the outer perimeter of the plant, and all show the ring.

Thanks for your help!

[WhiteRabbit]

[WhiteRabbit]

anybody?

[trdyl]

Hi Sonya,

I am not sure. It could be but then again it could be "normal" color. You might try cutting into a newer growth and check. But I have to say I have had a few plants with a worse looking ring for years without any other symptoms.

[LizB88]

Hope you win this one

I found this link Orchid Diseases

Hope that helps, and good luck

[james mickelso]

Sonya, this looks suspiciously like fusarium wilt. Staugorchids has a pic that looks just like yours. Pink or purple layer around the floem of the rizome. Slowly wilting leaves\\se and general decline of the plant over a year. Sorry. It is fungal in nature.

[Island Girl]

^ Yea, I agree... I have no experience in this particular disease, but this does look a lot like the pictures on their website... this is the St. Augustine O.S. webpage, & Fusarium Wilt is down the page a little, 4th one down. Good Luck!! I hope you can save it! My fingers r crossed for u!

Orchid Diseases

^that is what James was referring to I believe (I have their website bookmarked up the wazoo, lol)

[Greenthumb.5]

It can be a fungus but also consider that its most likely a virus as I have seen on one of the Cattleyas I tried to rescue one time. I got rid of it before infection took place.

[WhiteRabbit]

Thanks for the input everyone.

Plant appears healthy otherwise. My previous experience with fusarium, the plant had been declining, and I discovered the (much worse looking) ring in the rhizome, but that is why I was concerned seeing the ring in this one.

This is a no i. d. plant, and while it grows exceptionally well, and holds some sentimental value to me, it seems the summer climate here is too dry and/or hot for it - it gets many spikes in spring, but they always abort; and then I usually just get one blooming spike in the fall from this quite large plant - so, no attempts will be made to save it. And if there's any possibility of virus especially - it's getting trashed. I need to get rid of some plants anyway ... May as well start with a likely diseased noid ...

Thanks again to all

[james mickelso]

Sonya do you have a place out in the garden where this might reside amongst the perrenials and shrubs? Just a thought. Let it die of it's own accord.