Cattleya Experts : Purple Ring (fusarium?) on rhizome

[NYCorchidman]

From what I understand, if there is a purple ring on the cut section of rhizome, it is a manifestation of the dreaded disease fusarium (I forgot which strain) that will slowly kill the plant over a long period of time. I read that it can take over one year.

Last spring, I tossed about all my cattleyas after I saw these purple rings on the cut section of their rhizome.
Blc Lemon Schiffon had rather serious case where the purple ring was very thick and dark. The roots were bad, so I tossed without a question.
Then a few more BLCs that were apparently healthy and growing and flowering fine also had this very thin but slightly purplish ring.
I tossed all but kept this red flowering cattleya, Blc Cherry Suiss. I had it for about three years now and it has been doing well although I did get lazy with watering too much. This particular plant had the thin purple ring but I kept one division and gave the other division to my aunt.
Now, after a year, I just made an incision on the rhizome and I see this thin purple ring again and I am not sure if I have to toss the plant before having it spread everywhere. I probably already have since this plant has been around for three years.

The thing is the plant has been growing and flowering every year like it should.
So experienced and observant Cattleya growers, what would you do? Are you supposed to see clear green cut section to be sure that plants are free from fusarium?

So far, I have seen only two cattleyas without a hint of any purple ring when cut on the rhizome.

I am going to cut my Cattleya maxima later in the evening and hope to see no purple ring because I paid a lot of money on that thing.

Please help!!!

[Leafmite]

I think you would see other signs if it was indeed that. The leaves tend to look as though they are deprived of water and above the infection, the pseudobulbs become wrinkled. The ring is the dead cells and because the cells are dead, the orchid cannot transport water and nutrients to the leaves so they begin to die.
If your orchid is not suffering in this way, no, it is not that.

[NYCorchidman]

I ended up tossing the plant.

I cut one of my nodosa and Cattleya maxima, and none had any rings. phew~