winter I had a sticky honey-like substance on two plants: a
schefflera and an unidentified plant. It has thick, dark green leaves
growing alternately on a tall trunk. It's a succulent of some kind
with sprays of flowers at the top which last for months. The
honey-like substance dripped onto a table and rug. It is difficult to
remove. In the summer all my plants went on the covered patio. This
substance disappeared. Now that the plants are back in the house, I'm
afraid this condition will return. What is it? What causes it and
what can I do about it? Thank you for any advice you can give.
sticky substance on your plants is commonly called
"honeydew." It is a secretion of many different types of
sucking insect pests that attack house plants. As the leaf surfaces
become covered with honeydew, the plant can become susceptible to a
disease called sooty mold. This disease turns the leaves dark gray,
sometimes covering the entire leaf surface. The honeydew disappeared
this summer when you placed the plants outside because the insect
pests that were causing it probably fell victim to their natural
predators and were destroyed.
Aphid, scale, mealybug, and whitefly are four sucking insects that
secrete honeydew. All attack a wide variety of house plants. The key
to preventing honeydew is to control the insect causing it.
Aphid is a very small, soft-bodied insect. It's usually no more than
an eighth of an inch long and is most commonly green, although there
are also black, brown, gray, and yellow types. Aphid chews on all
parts of the plant. It congregates on stems and underneath leaves as
well as on flower buds. Aphids bear live young and they multiply rapidly.
Scale is an insidious insect pest because it covers its body with a
hard shell, making it impenetrable to insecticides. In its juvenile
crawling stage, scale is a small, round, pale tan or yellow insect
that is no larger than the point of a pen. All house plants can be
infested with scale, however ferns seem to be especially affected.
Mealybug is a small white insect that clusters together in groups on
the undersides of leaves and along stems. It is easily identified by
the white, cottony substance covering the insect.
Whitefly is a tiny, white insect that attacks a wide variety of
houseplants. Some of its favorites are fuchsia and poinsettia. They
live and feed on the undersides of leaves and when a leaf is brushed
or disturbed, they fly up in a white cloud.
The best way to control aphid, scale, mealybug, and whitefly is with Neem
Oil. Neem Oil is an
organic, three-in-one spray that controls insects, diseases, and
mites. Spray the entire plant at the first sign of insects and spray
once a week or so to eliminate them. As a preventative, spray your
plants about once a month.
Check all plants you bring in this fall from outdoors to make sure
you aren't bringing any pests indoors. Also, any plants purchased
over winter should be quarantined for at least a week or more to
monitor for signs of pests and diseases. If you see a problem, treat
it immediately, since a serious infestation can occur in a very short
period of time and can easily spread to other plants.
Click here to read more about Neem Oil and
order it from Pernell Gerver's Online Store.