Ask-a-Dave's-Gardener: Leaf problems with new-ish indoor plant, 2 by ToddinBC

ToddinBC wrote:
Hi there,

I recently inherited a nice floor plant which I was told was of the Yucca variety and had it in my place for about a month now. I've been getting some nice new growth, but at the same time have been getting some yellowing of leaves and some black spots have been appearing on certain leaves.

Can anyone tell me what's causing the discoloration? I'm trying not to overwater as I was told Yucca's thrive on "neglect". And are the black spots a fungus?

Thanks in advance.

-Todd