Answer: Dieffenbachia likes medium light, so I think the dead spots on the leaves are sunburn. I'd move the plant. A good place would be in front of an east window, where it would get a little morning sun, then light but no direct sun for the rest of the day. The plant can adapt to lower light levels, like in a north window or in a bright room but away from the windows. It will tolerate brighter light, but full sun might be too much for it. Try moving your plant away from bright light and see if that doesn't make a difference.
Q&A Library Searching Tips