This looks like frost damage to me. If it is in a cold exposure situation I would withold water, they can go a very long time without a drink, especially in winter. The damaged leaves will continue to dry up and could be removed without hurting the plants health. Can you move it to a warmer area or cover it when the temps dip below 40F? This is not a cold hardy Agave. It is a zone 9 to 11 plant. This could help it from happening again. These guys are generally hard to kill but sometimes easy to beat up.

Hope this helps,
Gil

Hi,

Thanks for the advice.
I will move it to a warmer place but initially it seemed to me strange because i have a lot of cacti and even euphorbia that don' seem to care about this minimum temperature(3 degrees and not -3 degrees).
I thought that agave were even tougher.

Best regards,

Hans

Sorry for the misunderstanding.
The minimum temperature is 3 degrees and all of my other cacti and even euphorbia don't seem to care.

Greetings,

Hans

If it is an Oxaca native, it should be used to more warmth. According to the site below the minimum is 5 degrees C, and it sounds like your temp is too low. I assume you are giving your temp in centigrade.

Do you have a dehumidifier? That might help. You might want to watch the lower leaves for rot progression to the stem. If that occurs, it can kill the plant.

You also need to make sure you have the right soil mix.

http://www.aridhouse.btinternet.co.uk/aridhouse/agaves/agave_macrocantha.html