Common Houseplant Pests and What You Can Do to Get Rid of Them

Spider Mites:

Spider mites are extremely small pests that live in colonies on the undersides of leaves and suck sap from plants. They are destructive and often difficult to spot due to their tiny size. They spread quickly from plant to plant.

• Identification: Oftentimes the problem can first be identified by unevenly yellowing or white spotting on leaves. If you notice this, you will want to inspect the underside of the leaf, especially near the vein. If you see white dots, similar in appearance to dandruff, spider mites are likely behind the issue. In large infestations, you will also see tiny silk webs along the plant and its leaves. 
• Treatment: If your plant has spider mites you will want to first move it away from any other nearby plants. Next, clean the leaves with warm, soapy water to remove the spider mites. Then spray the leaf tops, undersides, and soil with neem oil. Reapply the neem oil to the infected plant every week for two additional weeks to ensure the problem is resolved. It is also a good practice to treat the plants that were in close vicinity to the infected plant. 
• Prevention: Any time you bring home a new plant, you will want to inspect it for spider mites. Certain plants, such as calathea, alocasia, and many palms, are more susceptible to spider mites, so it is a good idea to frequently check their leaves, as well. Spider mites usually occur when conditions are warm and dry, so increasing humidity is one way to help deter them. You can also spray neem oil on them as a preventative measure.

Fungus/Soil Gnats:

Fungus gnats are small gnats that will feast on fungus and lay eggs in wet soil. The gnats themselves do not cause damage to houseplants, they are more of a nuisance. However, their presence is an indicator your soil is staying wet too long, wet soil can lead to root rot.

• Identification: Fungus and soil gnats are dark-colored gnats that look similar in appearance to fruit flies, living in and around your houseplants’ soil. They will fly into the air when disturbed. 
• Treatment: The easiest way to get rid of soil gnats is to eliminate their food source and breeding grounds, which means evening out your soil moisture. You will want to pour out any drainage dishes and let your soil dry before watering again. One trick to speed up this process is to cut up a potato, stick it in the soil for about an hour, and then remove it. The starch in the potato will absorb excess water from the soil. In the case of a bad infestation, you may need to replace your potting soil and sterilize your container. Sticky strips/traps can be useful in catching adult gnats/flies.
• Prevention: The best prevention is to make sure you are watering in a way that eliminates excess moisture in the soil and removing any standing water from your indoor space. Additionally, you may apply a systemic houseplant control to the soil as a preventative measure.

We suggest using Bonide Systemic Houseplant Insect Control Granules for your houseplants. We have this product for purchase in our retail store. When you visit our retail store be sure to ask our associates which granules are best for your plants. You can also find similar granule products in a nursery or gardening center near you.

Mealybugs:

Mealybugs are small pests related to aphids that suck the sap from the stems of plants. They like to form protective colonies along the stem, especially at leaf joints.

• Identification: These small insects have a waxy coating that makes them white and fluffy in appearance, resembling bits of cotton or wool. They often gather in clusters along the stem and sometimes on the undersides of leaves. Yellowing leaves and stunted growth in your plant are a sign of this infestation. You may also see ants or black mold feeding off of the sweet, sticky mealybug excretion known as honeydew.
• Treatment: You will want to start treatment as soon as you spot signs of this insect. The outer coating of mealybugs acts as a highly effective protective shield, making most insecticides ineffective. Instead, you can rid yourself of this pest by wiping them from the plant stem using a cotton pad soaked in rubbing alcohol, while being careful to not damage any of the foliage. Do this daily until all signs of the mealybugs are gone. It is also important that during treatment you water your plant sparingly, as this will help to starve the mealybugs. You can spray neem oil and insecticidal soap, keeping in mind this works best on young nymphs as opposed to the eggs or mature mealybugs. 
• We suggest using Bonide Insecticidal Multi-Purpose Insect Control Soap. We have this product for purchase in our retail store. You can also find similar insecticidal soap products in a nursery or gardening center near you.
• Prevention: Similar to spider mites, mealybugs often find their way into your home via new plants being brought home. Be sure to inspect your new plants thoroughly. Mealybugs are attracted to moisture, which is just one of the many reasons you will want to be careful to make sure that you do not overwater your plants. 

Scale:

Scale are small, smooth stationary insects, that also related to aphids, which live on plant stems and leaf joints, sucking sap from these tender areas. 

• Identification: Scale are often hard to spot until larger colonies form, allowing one to notice their bumpy clusters along leaf stems. Since these insects are not highly mobile pests, they are often mistaken for growths. Unlike growths, they easily flake off of the plant with the use of a toothpick, or fingernail. They are most commonly brown but they can also can range in color from white to reddish, and vary in size and shape. Like other pests, scale infestation causes stunted plant growth and yellowing, dying leaves. You may additionally see deformation in new growth, wilting, and the presence of ants or black mold feeding off of the insect’s honeydew.
• Treatment: Scale have a protective coating which makes them impermeable to a large number of insecticides. It is best to physically remove them from your plant. You can also use a cotton pad soaked in rubbing alcohol to kill the scale on contact. This pest can live in soil so after an infestation, so we recommend re-potting your plant in a sterilized pot or container with fresh potting soil. Be sure to check the stem just beneath the soil when you do this. Scale will hide in crevices so be thorough in your examination. Neem oil can be used to kill young scale, called crawlers.
• Prevention: Scale can be brought into your home through contaminated soil or via plants that were allowed to be outdoors during the summer months. Therefore, whenever you pot a plant make sure you use clean potting soil and a sterilized pot to avoid scale contamination. 

Thrips:

Thrips are active pests that quickly crawl and fly between house plants, feeding on the sap and leaving black droppings on the plant.

• Identification: These often dark-colored flying insects have long, skinny bodies and pointed tails. Unlike fungus gnats, they locate more on the plant than the soil, especially on the undersides of the leaves. An infestation will often lead to brown stripes or spots on your leaves, leaving portions of the plant dying, while the leaves are dropping. 
• Treatment: Thrips are easily controlled with the use of insecticidal soap or neem oil. Both will kill thrips on contact. Be sure to re-apply to the undersides of the leaves weekly for at least three weeks or until the problem is resolved.
• Prevention: Overly dry conditions may encourage thrips, so make sure to water your plants adequately during warmer seasons, especially houseplants which are allowed to be outdoors during summer months. Thrips most often will enter the home via plants that have been kept outside.

Aphids:

Aphids are small, common sap-sucking insects that crawl along plant stems and reproduce quickly. They are also known as greenflies and blackflies, depending upon color.

• Identification: This plump pear-shaped pest is often found in clusters on areas of new plant growth. While often green, they can be a range of colors and have wings or not. Like with other relatives, aphids produce excrement called honeydew which attracts ants and a black fungus. Infestation leads to wilting, stunted growth, death to infested areas of the plant, yellowing leaves, and plant deformation.
• Treatment: Neem oil and insecticidal soap spray can be used to dislodge and suffocate aphids on contact. Being soft-bodied, aphids can easily be crushed once dislodged. Alternatively, rubbing alcohol on a cotton pad will also kill aphids on contact. Due to their prolific nature, weekly re-application will likely be needed. 
• Prevention: Aphids often enter the home via plants that have been kept outside during the summer. Close investigation of your plants can help prevent their entry into your home.