Question
Hi Tracy!
  I have a Madagascar Dragon Plant at my house, and it's leaves are covered in black, sticky junk.  It's not growing any new leaves, and the old ones are getting nasty and falling off.  I really don't want to get rid of the plant, but I don't know what to do with it. Could you give me some advise?
                Thanks!
                   Hannah

Answer
Hi Hannah,
It sounds like you have a bad insect infestation. Most of the sucking insects, like aphids and mealybugs secrete a substance called 'Honeydew'. Honeydew starts out as a clear,thick, sticky liquid that covers the leaves. After a while sooty mold will grow on the honeydew and turn into the black, sticky junk you mentioned.
It sounds like the infestation is quite bad and there is extensive plant damage so the plant might not recover. The best thing, especially if you have other plants in the house, is to throw it out. If you want, you can try to save the plant, I have seen some plants come back from certain death. Look the plant over carefully and check the underside of the leaves, use a magnifying glass if you have one. You can see most insects but if you have spider mites all you will see is webbing on the leaves and stems.
Put the plant in the bathtub or outside if the weather is warm. Using a strong spray of water clean the leaves and stems, be sure to get the underside of the leaves to wash off as many of the insects as possible. Once the plant is clean and dry, spray the plant with an insecticide. I would recommend using a 3 in one spray made from neem oil because it is an insecticide, and a fungicide or you can use insectical soap. Repeat the treatment every 5 -7 days until there is no sign of insects. Don't forget to carefully check all other plants you have in the house and treat them too if you find any sign of insects. Here is a good website you can check out to help you identify what insect it is that you have.    http://www.ag.ndsu.edu/pubs/plantsci/landscap/pp744w.htm
( The section on insects is at the bottom of the page)
I hope this helps. If you have any questions let me know.

Tracy