The brown tissue has been dead for quite some time.

If that's the only damage on the plant, it's not important.

Please share a few facts--

Start w/ indoors or outdoors? Container or the ground?

Any chance of posting an image of the entire plant?

The plant is in a container on my terrace in Costa Rica. The terrace is covered so the plant does not receive too much water. I've treated the plant with chlorothalonil, but the leaves continue to die along the edges.

Could be bacterial infection OR fertilizer burn.

no plant holds its leaves forever.. are these the oldest leaves???? if so.. maybe its time for a little pruning.. to force the energy to the new growth.. rather than waiting it on the old stuff..

a pic of the whole might help

ken