Houseplant Insect Pests Entomology Houseplant Insect Pests Several species of scale insects, mealybugs and whiteflies are commonly found on plants in the home or greenhouse. All are sap-feeding insects that can weaken plants and cause poor, stunted growth. Death of infested plants occurs only in severe cases. Houseplant insects may create an annoyance caused by large quantities of a sweet, sticky liquid waste product called honeydew that is excreted as the insects feed.
Honeydew can make a sticky, shiny mess on the plant and nearby furniture and floors.
A black fungus called sooty mold may grow on the honeydew. Scale insects have a tan to brown shell-like covering or scale that protects the insect's body. Some scales are hemispherical in shape, while others are oval and flat. Mealybugs appear as white tangles of cotton on the leaves or stems. A common location is the slim, protective gap at the junctions of stems and leaves.