Question
hi!
some of my african violets leaves have changed color. it starts as a thin line of light tan around a section of the leaf edge. then the thin line goes around the entire leaf edge. then the line of tan becomes thicker until almost the whole leaf is affected, and the green remains only in the center. its not something ON the leaf...the actual leaf is changing color. i thought maybe i could stop it by pulling off the affected leaves, but it still "spreads". the plant seems to be healthy other than that, and is flowering. the leaves are not wilted or soft. i have quite a few african violets and i'm very worried this is a disease that will "wipe me out".
thanks so much!
celeste

Answer
Celeste,

It is very difficult to diagnose a plant just by description.  I have never experienced this occurance in my own collection.

From your description, I would say it MIGHT be a disease called TOBACCO NECROSIS NECROVIRUS.

Many strains of this virus affect gesneriads.  This is transmitted by a vector, a fungus, Olpidium brassicae.

This will eventually cause death to the plant.

Damage and symptoms are leaf and stem rot.

There is no natural control.  No biological control is recommended.  And chemicals will not help if it is indeed this virus.

I could be wrong since I am not able to see the plant.  But take any plants with symptoms and isolate them.  I would think it best to destroy these plants if they show no signs of improvement.

You can try fungicides such as Banrot, Fung-away, and others but I don't think this is going to help.

Can you get one or two specimens in to an extention office or perhaps a botanical garden where someone can make a more accurate diagnoses.

These will infect your collection so if possible, take a healthy leaf and plant it but isolate it as well.  Destroy badly infected plants.

I have heard others in my circles that have been having trouble with too high humidity and plant rot so this is becoming a problem.

If at all possible get a few plants in to someone who can diagnose your problem correctly.

Isolate carefully all plants showing symptoms.  Destroy those that don't seem to improve.

I am sorry to be the bearer of bad news.  Do try to get a good diagnoses from someone who can see the plant.

Nancy