Question
Hi it sounds like you have had a similair question recently but I would like to clarify the symptoms.Along the blade of the leaf usually starting on the upper face  the outer surface seems stripped away in small pieces that grow larger with time.The remaining flesh is dry and semi translucent devoid of colour.On the underside blobs of clear sap appear and then general yellowing and rotting starts along the leaf blade.I live on the south coast of the uk and have had large agaves for some years in pots and have never had a problem before.The disease is affecting both older plants which I know where propagated in the uk and their younger offspring which i am trying to grow on.The younger plants are a good distance from the older.The older plants are about 6 or 7 year old and about 3x3 ft.

I have read your previous answers on this but am not sure if they related to the same problems.
Have a good holiday and i look forward to your reply.

Answer
Hi

If the plants have not been fertilized in the last couple of yeas I would say you are possible describing a nutritional deficiency.  Potassium will cause the death of the margins of the older leaves which will progress inward until the leaf is dead.  The other cause may be extreme environmental changes such as temperature.  See if either of these makes any sense.  If this doesnt seem to be the case, please respond back and we will go in another direction.  Good Luck.