Connecticut Garden Journal: Houseplant Pests
Houseplants not only do provide soothing greenery in winter, they also bring in some pests! There are a number of houseplant pests you're probably seeing right now. Here are three main ones.
While sitting, sipping coffee in the morning you may notice small black flies buzzing around you. These, most likely, are fungus gnats. Adults lay eggs in potting soil and the larvae feed on the organic matter. They emerge as adult flies that do no harm, but are a nuisance. To control them, repot your houseplant with fresh potting soil, add a layer of sand on top of the potting soil to prevent successfully egg laying and try organic controls, such as Mosquito bits, to kill the larvae in the soil.
If you see white, cottony growth on your fig, rubber plant or other large houseplants and the leaves are sticky, you may have mealybugs. These insects suck the plant juices and exude a sticky honeydew as they go. Control these pests by taking a cotton swab, dipping it in rubbing alcohol and dabbing it on the mealybug. They will die quickly and your plant will be safe.
I noticed webbing on my 'Meyer' lemon last week. After inspecting it with a magnifying glass I saw these tiny, red insects running around on the bottom of the leaves. These are spider mites. They also suck plant juices causing the leaves to yellow. Spider mites like dry air, so discourage them by misting plants regularly, placing your plants on pebble trays filled with water that evaporates around the plants or using a humidifier. Kill mites with sprays of insecticidal soap.