Black Bugs on House Plants

House plants require regular inspections for the presence of insects.

A number of insects, many of which are capable of causing extensive damage, plague house plants, according to Colorado State University Extension. If you catch the pests early enough, however, you may safely eliminate them and keep your plant healthy.

Black Bugs

Fungus gnats and spider mites are common insect pests that appear as small black bugs on house plants. Thrips also invade house plants. Spider mites are not black, but they have two black spots on their backs and may look like two tiny black bugs. Fungus gnats have wings. Thrips are very tiny---about 1/16 inch---and look like black specks of dirt.

Control

Controlling bugs on house plants starts with isolating the infested plant from others to prevent the infestation from spreading. A strong stream of water from a hose washes bugs from plants. Sticky yellow bug traps offer the best way to catch flying bugs, such as fungus gnats.

Prevention and Symptoms

Insecticidal oils or soaps are effective at preventing bugs from infesting your house plants. They are effective as preventive measures, or when you first notice symptoms of bug damage, such as holes in the leaves. Other symptoms of bug infestation include a sticky substance on the surface around your plant. This is called "honeydew" and it is excreted by many bugs that infest houseplants. This substance often attracts ants, so ants around your plant may indicate the presence of other bugs.

References

• Colorado State University Extension: Managing Houseplant Pests
• University of Minnesota Extension: Houseplant Insect Control