Mealybugs on Houseplants
Several of my houseplants are covered with something that looks like bits of cotton. There is also a clear sticky substance on some of the leaves. What is it and how do I get rid of it?
Underneath the cottony fluff is a soft bodied scale insect known as a mealybug. These insects feed on plants by inserting their needle-like mouthpart into the leaves or stems. They suck plant juices eventually causing leaves to yellow and brown. Severe infestations can stunt the plant. These insects, like mites, aphids and whitefly, secrete the excess plant juices as a clear sticky substance called honeydew.
The cottony covering is really a mass of waxy filaments that help the insects conserve body moisture and repel water and chemicals. This makes control difficult. Start by physically removing the mealybugs. I prefer the cotton swab and alcohol method. Touch each individual or mass of mealybugs with an alcohol soaked swab. The alcohol dissolves the covering and kills the insect below.
Check along the stems, under the leaves and where the leaves attach to the stems. Repeat every other week until the problem is under control. Speed up the process by using a lightweight horticulture oil or insecticidal soap labeled for use on houseplants. Thoroughly spray the plant and upper lip of the container after killing the adults with the alcohol. This treatment helps kill the immature mealybugs that have not yet developed as dense a covering.