I'm new to aroids, but I've been growing this Colocasia (not sure of the species) for about a month. Last night I noticed that the very first leaf it ever had, is starting to wilt - or for lack of better words, die. Last night that leaf was very latex-like and wilted, like it had no structure. It also has a smell. The other leaves on the plant are fine as pictured. As of this morning, the leaf has dead 'spots' that kinda feel like latex, it's stretchy.
It's dying alright. However my guess is it's not likely to spread to other leaves. Natureman, I'd move this thread down to Araceae; I don't grow Colocasia, but a bunch of the other Aroiders do, and they will be more likely to see it there.
It's definitly getting lots of water, other leaves are fine, and there's visible guttation on the newer leaves. :)
As "trikus" said "no leaf last forever, just old age maybe". If that was my plant I would cut that leaf off.
I'd cut it off... I'm not into Colocasias, but that does not look like a leaf dying of old age to me - looks more like it's been infected by something.