Fall is the time to bring those winter-sensitive plants indoors and sometimes pests are brought along with them. There are three main groups of pests that tend to show up on houseplants.
The first are fungus gnats. These are tiny dark flies. The larvae of fungus gnats feed on the plant roots and moist organic matter. The first and most important thing to do is to reduce the soil moisture. And so this is a typically a problem with overwatering. So cut back on the amount of water and the frequency of watering. Another thing you can do is repot the plant with new sterile soil. Finally, there’s an organic insecticide made with a bacterium called BT. You apply this as a drench to the soil to kill the larvae that are feeding there.
The second group of pests is spider mites. These are tiny, tick-like animals that feed on plants. Infestations tend to start on the underside of leaves. They cause a stippled or speckled look and the leaves will turn yellow and then they take on a dusty appearance when the mite populations are high. Put the potted plant in a sink and vigorously wash it down with water to remove the spider mites from the leaves.
The final group of pests is sap feeders. These are insects that feed with a straw-like mouthpart into parts of the plant. All of these pests produce a sticky honeydew. Use a diluted alcohol, 25 percent concentration, and rub it on the leaves where these pests occur with a cotton ball.
Good lighting, regular watering schedule, but don’t over water, and good drainage are keys to happy houseplants through the fall and winter.
This is Diane Alston with USU Extension here for your Green Thumb tip.