How to tell if Phalaenopsis has fusarium?
 

Hello All,

I had a question regarding fusarium in phalaenopsis orchids.

While there seems to be a good way of diagnosing fusarium in cattleyas (the presence of a purple ring on the rhizome), how does one know if other orchid genera are afflicted with fusarium?

For example, one cannot realistically cut into a phal to check for rings without mortally wounding it and I hear that the purple ring phenomenon is only really true with cattleyas (I once brought a zygopetalum with such a brownish ring around the rhizome to a repotting expert who did not seem to think it could be fusarium).

I ask because I accidentally splashed a fair amount of water from a new phal that I got from a flower delivery service as a gift onto another phal or two nearby. I heard this is how most fusarium infections spread. None of the plants appear to be sick to my eye. How long would it hypothetically take for symptoms to show if any of them were infected and what would those symptoms be?

Yes, it can be spread through splashing or sharing water. Symptoms are that it would look extremely parched, like you forgot to water it for a long time and left it sitting on top of a heater. I remember looking at an article a while back with pictures of Phals with fusarium, I will see if I can find it, but they looked like crap. It was very obvious that something was definitely wrong. I don’t remember how long it takes for symptoms to show up, but I believe it was a matter of weeks.



Even that is not 100%. I had received a really awful looking Cattleya walkeriana that had some dead or dying old back bulbs that were shrunken, had no good roots on them, lots of black streaking or patches, and they needed to be removed. That one had a purple ring on the inside of the rhizome when I divided it. However, the newest growths still looked ok with no sighs of dehydration or dying pseudobulbs. I didn’t even bother treating it with anything and it’s fine. It might have been some sort of old fungal infection, could have just been age, but if it was fusarium, it would have been long gone by now.

Basically: don’t go cutting up a healthy looking plant just to look for an issue, practice good hygiene and care, and keep and eye on your orchids and you should be ok:)

:bowingSaraJean is exactly correct

I believe you can have a leaf tested for it, if you are really desperate to know.

But I'm not an expert, so not 100% on that.