Many houseplants are susceptible to infestations of one or more types of insects, most of which are easily controlled by acting quickly and using patience. This guide serves to provide a quick overview of general houseplant pests and advice on how to diagnose and deal with them.

The easiest way to keep your houseplants pest free is prevention, and the next best way is recognizing a pest problem before it becomes an infestation that really damages or kills the plant. Houseplants should always be checked for pests prior to purchase and should be isolated from other plants for up to two weeks to allow any undetected pests or problems to manifest themselves. Note that stressed plants are more likely to develop insect problems. Gently dusting leaves with a soft moist cloth (use a separate cloth to prevent transferring insects between plants) or showering plants on a regular basis can help in keeping foliage clean and preventing insect problems, in addition to increasing the amount of light that actually reaches the leaves of your houseplants. Using sterilized soil that is well draining is also an easy way to prevent soil based pests or growth of fungus and bacteria. Next, keep a eye out for speckled or fading leaves by checking them thoroughly and on a regular basis, being careful to watch for anything sticky on leaves or the areas around the plant.

A alphabetical summary of common houseplant pests and recommended solutions to treating each is given below:

Ants (somewhat uncommon)

Finding ants near your houseplants generally is a cause of an aphid related issue, as they are attracted to the honeydew left behind by aphids. Aphids are easily treated by thoroughly showering an infested plant, and this usually rectifies the ant problem.

Aphids (somewhat uncommon)

Although not extremely common on houseplants, aphids are small insects up to one-eighth of an inch long and can be black, gray, orange, yellow, red, or green. They are usually found on the undersides of leaves, at stem apexes, on new growth, or on flower buds. They are usually noticed in clusters, and they feed on the juice of plant stems by sucking sap, and they excrete a sticky honeydew byproduct similar to scale insects. Aphids are easily controlled by showering affected plants. Severe cases may be treated by using horticultural oil. Outdoors, aphid infestations may be controlled in affected plants by releasing ladybugs, which are natural predators of aphids.

Aphids are shown attacking the underside of a leaf.

Cyclamen Mites (very uncommon)

Although uncommon on houseplants, cyclamen mites are closely related to spiders and ticks, but are not true insects. They can generally be found on young leaves, flower buds, and flowers. Cyclamen mites are minute and are somewhat transparent, such that they cannot generally be seen without using magnification. Infestations are characterized by stunted leaf growth and deformed buds. Ivy plants that have cyclamen mite infestations develop stems that have no leaves or have small hairy leaves. African violets that are infested with cyclamen mites often have small hairy leaves in their centers. Cyclamen mites are not easily treatable and the general remedy is to discard any infested plants to prevent spread to other houseplants. Note that cyclamen mites are often spread on clothing.

Leaf deformities on an African Violet are caused cyclamen mites.

Fungus Gnats (common)

Fungus gnats are tiny black flies that live in overly moist soil, usually within the top two inches. They will generally disappear by watering affected plants less often, and are a common sign that a plant is being overwatered. Note that eggs may live up to three weeks in dry soil until they are fully desiccated and will no longer develop larvae. Sticky traps are a good trap and detection method for fungus gnats. For severe infestations, plants may be removed from infested potting soil, washed thoroughly, and repotted in an appropriate sterile potting mix.

Adult fungus gnats are attracted to sticky yellow traps.

Mealy bugs (common)

Mealybugs infestations look like cotton clumps and a significant portion of houseplants are susceptible to them. Mealybugs are generally found at stem and leaf apexes, and sometimes in the roots. They damage and sometimes kill plants by sucking sap and juice out of the stems. However, mealybugs are easily treated by repeated applications of using a cotton swab doused in rubbing alcohol to wipe off all affected areas. The process should be repeated at least two more times in 3-5 day intervals until the plant is no longer affected and all eggs are hatched and removed. Root infestations may be treated by thoroughly removing and washing off all infested soil, and then repotting in an appropriate sterile soil. As a last resort, severe infestations may be treated by spraying the plant with a houseplant insecticide labeled for mealybugs. Note that horticultural oil, which works by smothering insects, is generally not effective as a treatment for mealybugs.

Mealybugs leave cottonlike clumps on afflicted leaves.

Scale (common)

Scale insects are found on the undersides of leaves and on stems, have a hard outer shell, and secret honeydew similarly to aphids. They may be treated by manually removing them or by using a cotton swab or moistened cloth to detach them from plant stems or leaves. Severe infestations may be treated with horticultural or neem oil to smother them. Note that insecticidal sprays are generally not effective for scale insect problems because of their outer shell. If scale insect infestations are too severe and are already cause yellow stems and excessive leaf loss, discarding the plant is usually advisable.

Scale is shown on a stem apex and separately on the bark of a tree.

Spider Mites (common)

Spider mite infestations on houseplants are usually noticeable by white webs that appear on stem and leaf apexes. Spider mite infestations usually proliferate in hot and dry environments, and are easily treated by showering an infested plant thoroughly and then ensuring that it has increased humidity levels. Humidity may be increased by placing plants on pebble trays, misting leaves regularly, or using a humidifier. Insecticidal sprays are not recommended for spider mites, as they are easily treated by washing and raising humidity.

Spider mites produce webbing between plant leaf and stem apexes.

Springtails (somewhat common)

Springtails are approximately one-sixteenth of an inch long, usually gray or white in color, prefer damp conditions, and are most likely found in peat-based soil or other hiding spots such as saucers or under pots. Springtails feed on decaying matter such as rotten roots and fungi. Springtails are generally an annoyance as they rarely damage plants. They are a sign that a plant is being overwatered and are easily controlled by watering less often.

Springtails thrive in damp environments.

Thrips (somewhat uncommon)

Thrips are approximately one-sixteenth of an inch long, are usually white yellow, or brown in color, can jump when mature, and feed on leaves by scratching them and then sucking the juice. Although they generally do not flourish indoors, some thrips are acclimated to living on houseplants. Leaves on plants that are damaged by thrips sometimes become distorted and have silver spots or streaks, as do flowers and buds. Thrips are controlled by showering the plant thoroughly, or by using horticultural or neem oil with at least two applications at week apart for more severe infestations.

Thrips rarely flourish indoors, but can attack and severely damage plant leaves.

Whiteflies (common)

Whiteflies are tiny and usually white or off-white in color, resemble moths, suck plant juices and excrete honeydew like scale and aphids. They are easily noticed as they will fly after watering or moving a plant. Whiteflies can be a nuisance because they spread quickly and can reproduce quickly to cause severe infestations. Infestations may be treated by washing thoroughly and then treating with horticultural or neem oil. Severe infestations should receive a repeat application of horticultural oil, and persistent infestations may require that the plant be discarded.

Whiteflies can spread and reproduce quickly on the undersides of leaves when not remedied.