Good Morning Mark, 

Thank you for contacting the U of M Extension Service. 

Please click on the following link about elephant ear plants: https://hort.extension.wisc.edu/articles/elephant-ears-colocasia-alocasia-and-xanthosoma/

This information states:

Provide copious water and fertilizer as the plants grow, especially for those in containers, as they are heavy feeders.

I would inspect the underside of the leaves for any signs of mold, fungus or pest.  There is not a pest or disease of colocasia that I am aware of. 

Do you have drainage holes in the bottom of your pot? I know from personal experience these plants use lots and LOTS of water. I have place my container of elephant ear in a container that has a large tray under it. I fill the tray with water everyday, and water the container, if it has not rained.  These plants grow very well with their feet (roots) in water. 

I would put a tray under your pot, assuming it has drainage holes. Fill the tray with water every day and consider fertilizing the plant.  The plant will absorb the water from the tray. As the plant begins to thrive, prune off the damaged leaves. 

Good Luck!

Mark, 

Yes, I use a fertilizer like Miracle Grow. We recommend using 1/2 the recommended amount but fertilize more often. 

Good Luck!

You are welcome!