Question
I purchased a yucca tree a few months ago...I have two problems with it. first It has 3 stalks.  The tallest has gotten soft and has dark sappy looking stuff on the side of the stalk. All the leafs at the top have turned yellow.  Is this from too much moisture? I have moved it to a sunnier spot in the house and also quit watering it. My other question is that I have small gnats that I can't get rid of.  Any suggestions on both problems would be greatly appreciated.  

Answer
Lou,

Overwatering your yucca has caused both problems. You may be too late to save that tallest stalk.  The gnats are fungus gnats that are feeding on the rotting roots on the yucca and any other plants that may be overwatered. The yucca is a desert plant and as such needs to be in the sunniest location possible in your home and needs to be dry for several days before being watered again. Then do not give it so much water that the soil becomes soggy. Just give it enough to slightly moisten the soil. Then do not water it again until until it has been dry for several days again.

Your fungus gnats will disappear and the plant will grow new roots and be healthy again. Good luck.

Darlene