Pest Control: How to Get Rid of Common Houseplant Bugs
To help you keep your houseplants in the best condition, here's a guide to five of the most common bugs that can wreak havoc on stems, leaves, and nodes. Plus, our experts share how to get the infestation under control.
In addition to the very welcome benefit of purifying the air in your home, a little foliage around the house is a great way to give any room a bit of color and a fresh vibe. Unfortunately, though, houseplants tend to be as attractive to pests as they are to you, which can be a major problem for the plants' appearance, growth, and overall health. To help keep your greenery in the best possible condition, we're outlining the five most common bugs that like to call houseplants home, as well as our best tips on getting rid of them.
These tiny insects with soft green, yellow, brown, red, or black bodies typically linger on the underside of leaves, feeding on sap. Because of their diet, "aphids excrete a sugary secretion called honeydew," explains Daniel Scott, associate director for horticulture at the American Horticultural Society. Honeydew often promotes a black sooty mold that grows on the surface of the plant. "It does not infect the plant tissue," says Scott, "but a heavy coating can inhibit photosynthesis and not allow light to penetrate the leaves." Large infestations can lead to stunted plant growth and distorted, discolored foliage. They're especially common in succulents.
To get rid of aphids, wipe or spray infested leaves with a solution of water and a few drops of dishwashing detergent, or by enlisting the help of natural aphid predators, like ladybugs or lacewing. For plants that are heavily infested, carefully pinch off the stem to remove from the plant. Because aphids are attracted to moist soil and high nitrogen levels, it's a good idea to avoid overwatering and over-fertilizing your houseplants in order to prevent another aphid infestation once you've alleviated your problem.
These small, wingless insects, which have a cottony white appearance when grouped together, can usually be found on plant stems, leaves, and nodes (the area where leaves meet the stem). "Mealybugs are attracted to excessively succulent growth, which can occur as a result of overwatering and over-fertilization, especially with fertilizers high in nitrogen," says Scott. As they feed on the sap of plants, leaves tend to curl and turn slightly yellow, and plant growth becomes stunted.
You can get rid of the pesky insects by dabbing them lightly with a cotton swab dipped in 70 percent isopropyl alcohol (avoid touching delicate leaves) or spraying with a dish-detergent and water mixture (one teaspoon of soap to one gallon of water). Neem oil, horticultural oil, and insecticidal soap are effective against mealybugs, too. To prevent outbreaks, "follow a strategic fertilizer regimen as opposed to indiscriminate feeding," says Scott. If caught early, mealybugs can simply be wiped away with your bare hands.
Moth-like whiteflies typically congregate in groups on the underside of leaves, sucking on the sap of houseplants and causing stunted growth, yellowing, and poor plant health. The pests are also largely linked to the transmission of plant viruses.
To detect and control whitefly populations, use yellow sticky traps, but beware: "Sticky traps are indiscriminate," says Scott, "and will also capture beneficial insects, as well as loose articles of clothing!" One trap per room should be adequate. You can also use a diluted neem oil mixture (one ounce of oil per gallon of water), insecticidal soap, or horticultural oil.
Technically arachnids as opposed to insects, spider mites are super small, reddish pests that collect on the bottom of leaves, where they feed on plant fluids, leaving small dots behind with each feeding. Especially common in plants like English ivy, spider mites can cause plant leaves to yellow, dry up, and fall off. Webbing on leaves is also a common sign of spider mite damage.
The easiest and gentlest way to address the infestation is to simply hose down the plant with lukewarm water, says Scott; use a sprayer on small plants. "Because spider mites prefer high temperatures and low humidity, you may be able to manipulate the environment around your plants to discourage the infestation," he says. "Regularly misting the leaves of your plants with a spray bottle will help to increase the humidity."
Scale insects are small, sap-loving bugs that attach to a plant's stems, branches, and leaves. Some have a hard shell, others a softshell but both can threaten a plant's vigor or cause yellow or wilted leaves. They're often difficult to detect because their coloring is similar to that of a plant.
When infestation is light, use your hand or an old toothbrush to rub off these pests or use a cotton swab soaked in 70 percent isopropyl alcohol. Horticultural oil and insecticidal oil work too. Prune infested plant stems as soon as possible to avoid a recurrence of bugs.