I have two large Peace Lily’s that have a black greasy substance on the leaves, they have stopped blooming flowers also. They are 3 1/2 years old about 4 ft. wide, planted in the ground in a patio area that gets sun in a.m. and bright the rest of the day. Bloomed always until this black substance got on them. Help, what should I do?
Flower Shop Network’s Reply:
The black substance you are seeing is actually a residual mildew from an insect. You probably have one of the following pests on your plant: aphids, mealy bug or scale. Scale looks almost like a fungus and will usually be at the base of the leaves where they join the stem. Aphids and mealy bugs will be on the backs of the leaves. All of these insects damage the plant by puncturing and sucking from the backside of the leaves.
You can eradicate these pests by using any house plant insecticide. It may take several applications over a period of time to get rid of them for good. Consult you local nursery or garden center for additional help