Houseplants can fall prey to a variety of insects just like outdoor plants, but most are easy to get rid of. Here's a quick overview of the most common ones.
While houseplants are generally easy to care for, there are some common pests that can cause problems. Here's a quick look at them:
Mealy Bugs-These pests look like tufts of cotton and attack a wide variety of plants. They particularly seem to like Dieffenbachia, Coleus and Jade. Look for them under leaves and on stems where the leaves meet it. They can sometimes be found along the roots as well. They hurt plants by sucking juices out of the stems, weakening and eventually killing them.
To treat, moisten a cotton swab with rubbing alcohol and wipe them off. Repeat a week or so later in case any eggs were left behind. For a severe infestation spray the plant with an insecticide made for houseplants (check labels carefully!) or make a homemade spray by adding a tablespoon of rubbing alcohol and a half a teaspoon of dishwashing liquid to a gallon of water. Mix well before spraying. For root mealies, remove the plant from its pot, wash all the soil off of the roots and repot in fresh soil.
Aphids- These come in many different colors: black, gray, orange, and green. You'll find them clustered on the undersides of leaves, on flower buds and growing tips, and where the leaves meet the stem. In bad cases the entire plant will literally be covered in them. Aphids suck out plant juices and deposit a sticky substance known as honeydew. When a plant is severely infested it's not unusual to find the surfaces around it coated in it, and honeydew attracts another common pest: ants! It's important to deal with an aphid problem as soon as it's discovered as they reproduce very rapidly - the females are actually born pregnant!
If ants are found in and around houseplants, it's likely there is an aphid problem. Luckily they are easily treated. Simply take the affected plant and give it a shower under the tap, or if it's a large plant, in the tub, and let the water knock them off and drown them. If the infestation is particularly bad, spray with an insecticide made for houseplants or use the homemade spray recipe above, omitting the alcohol and increasing the dishwashing liquid to one tablespoon.
Scale- Scale insects attach themselves to the undersides of leaves and are protected by a hard outer shell, making insecticidal sprays useless. Like aphids, they secrete honeydew. For light infestations wipe them off with a cotton swab or damp cloth. For more involved infestations, try spraying with Neem oil. If an infestation is heavy and the plant has begun to turn yellow, disposal is the only option. Scale are particularly fond of Scheffleras.
Fungus Gnats- These tiny black flies are often found flying around plants. They lay their eggs in the soil and feed off the organic matter in it. Getting rid of them is easy as they live only in overly moist soil. Simply water less often and they will disappear. Fungus gnats are a classic sign of overwatering. If they are particularly troublesome, unpot the plant, wash the soil from the roots, and repot in fresh soil.
Whitefly- If an infected plant is moved, these tiny, moth-like insects will rise above it in a great cloud before resettling. Whitefly usually occur in large numbers and spread quickly from plant to plant. Getting rid of them is difficult; if spraying every three days with an insecticide meant for houseplants doesn't work, the plant should be disposed of.
Spider Mites- These are tiny spider-like insects that are hard to see with the naked eye. The first signs of infestation are white webs that appear between leaves and stems. Other signs are yellowing and wilted leaves. They thrive in hot dry conditions so it's important to keep your plants well humidified. Mist leaves regularly, especially in winter when central heating dries out the air or keep plants on a humidity tray.These pests particularly love Palms.
To treat an existing infestation, give the plant a shower under the tap or in the tub, and repeat in a week or so. If infestation is advanced to where the plant is losing leaves, spray with an insecticidal soap meant for houseplants.
To prevent infestations, choose new houseplants carefully. Look under the leaves and at the stems for signs of insects and resist the urge to rescue sad looking ones-most of the time they are that way due to an pest infestation. Isolate new plant purchases until you're sure they are insect free - and isolate any houseplants that may be infested until treatment is complete. Pests are attracted to weak plants, so keeping plants healthy and happy is the best prevention!
