How to Identify and Treat your Houseplants for these Common Pests

Nobody likes to find freeloaders in their houseplants but since plants are living things growing in their own self-contained environment, it is only natural that insects and other pests decide to make themselves a part of that environment. Although no plant and its pot can ever be completely free of all forms of living creatures, some of these are more unwanted than others. If you enjoy keeping plants at home, you must have all the information you need when it comes to common pests and how to identify and treat them.

Here are some common pests that home gardeners often face, how to identify them and instruction on how to properly treat that pest infestation: 

Mealybug

Mealy bugs are small insects and can be up to 1/8 to 1/4 inch long. These insects are very familiar with scales and move around sluggishly. To identify the insects, you need to look for white waxy material that makes the insects look like cotton. This is because the adult female Mealybugs cover their eggs and themselves in the white material. The material does not cover just their bodies; you may find filaments that protrude from them. 

This waxy material repels pesticides which makes it difficult to control Mealybug infestation. These insects are commonly found on the underside of leaves. 

Mealybugs can be a nuisance for houseplants, but there are several steps you can take to remove them:

  • Isolation: If you notice mealybugs on one of your plants, first isolate the infested plant from your other plants to prevent the bugs from spreading.
  • Manual Removal: Using a cotton swab or soft cloth dipped in rubbing alcohol, gently wipe off the mealybugs. This method is most effective if the infestation is not severe. It’s important to check under the leaves and around the stem, as mealybugs like to hide in these areas.
  • Insecticidal Soap: If the infestation is severe, you may need to use insecticidal soap. These are available at most gardening stores. Follow the instructions on the package for best results. Be sure to spray the undersides of leaves where mealybugs often hide.
  • Neem Oil: Neem oil is a natural pesticide that can be effective against mealybugs. Mix the oil with water according to the instructions on the bottle and spray it onto the infested plant.
  • Beneficial Insects: If your houseplant is large enough or if you have an indoor garden, you could consider introducing beneficial insects that prey on mealybugs, like ladybugs or lacewings.
  • Repotting: If the infestation is severe and the above methods don’t seem to be working, you may need to consider repotting the plant. Remove as much of the old soil as possible and replace it with fresh, sterilized soil.

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 Scale

There are two types of scales, armored scales and soft scales. The armored scale also creates a waxy covering; to locate the insect, you need to scrape the covering. This covering is not a part of the armored scale’s body. At the same time, the covering produced by a soft scale is an extension of its body. 

It is easy to identify a scale as it is a strange-looking insect. Their appearance can depend on different factors such as species, sex and age. While some of these pests are flat, others may look like fishy scales. These insects can be between the sizes of 1/16 – 1/2 inches. They are most commonly found on the inner part of the leaves or the stem. They survive off of the plant sap but suck it. 

Scale bugs can be a problem for houseplants, but there are several steps you can take to remove them:

  • Isolate the Infected Plant: Just like with mealybugs, if you notice scale insects on one of your plants, first isolate the infested plant to prevent the bugs from spreading to your other plants.
  • Manual Removal: You can often remove scale insects manually. Use a toothpick, small brush, or even your fingernail to gently scrape off the bugs. Be careful not to damage the plant in the process.
  • Insecticidal Soap or Horticultural Oil: You can use a solution of insecticidal soap or horticultural oil (like neem oil) to treat the infested plant. Spray the solution onto the plant, making sure to cover both the top and bottom of all leaves, as well as the stems.
  • Alcohol: Rubbing alcohol can also be effective against scale. Dip a cotton swab in the alcohol and use it to wipe off the scale insects. Be sure to get into crevices and undersides of leaves.
  • Systemic Insecticide: For serious infestations, you may need to use a systemic insecticide, which is absorbed by the plant and kills the insects when they feed on the plant’s sap. Follow the instructions on the product label for safe and effective use.
  • Repotting: If the infestation is severe and the above methods don’t seem to be working, you may need to consider repotting the plant. Remove as much of the old soil as possible and replace it with fresh, sterilized soil.

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 Whiteflies

These insects are a relative of scales and are extremely small. They can be up to 1/10 to 1/16 inch long. The appearance is powdery white; you may confuse them with tiny moths. When the insect is not moving, it rests its wings at an angle that creates a roof over its body. The insect feeds on the plant sap, which will stunt its growth if it infests your plant. 

The leaves will turn yellow and cause the plant to die. Disturbing the plant will cause the whiteflies to move around and hover over the plant while waiting for a chance to sit on it again.

Whiteflies can be a persistent pest on houseplants, but there are several steps you can take to remove them:

  • Isolation: If you notice whiteflies on one of your plants, first isolate the infested plant from your other plants to prevent the bugs from spreading.
  • Manual Removal: If the infestation is small, you can try removing the flies manually. Use a handheld vacuum to suck up the flies (do this early in the morning when they are less active) or gently shake the plant to dislodge the insects and then vacuum them.
  • Yellow Sticky Traps: Whiteflies are attracted to the color yellow. You can use yellow sticky traps, available in most gardening stores, to attract and trap the flies.
  • Insecticidal Soap: You can use a solution of insecticidal soap to treat the infested plant. Spray the solution onto the plant, making sure to cover both the top and bottom of all leaves, as well as the stems.
  • Neem Oil: Neem oil is a natural pesticide that can be effective against whiteflies. Mix the oil with water according to the instructions on the bottle and spray it onto the infested plant.
  • Beneficial Insects: If your houseplant is large enough or if you have an indoor garden, you could consider introducing beneficial insects that prey on whiteflies, like ladybugs or lacewings.
  • Systemic Insecticide: For serious infestations, you may need to use a systemic insecticide, which is absorbed by the plant and kills the insects when they feed on the plant’s sap. Follow the instructions on the product label for safe and effective use.
  • Repotting: If the infestation is severe and the above methods don’t seem to be working, you may need to consider repotting the plant. Remove as much of the old soil as possible and replace it with fresh, sterilized soil.

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 Thrips

Thrips are easily recognizable as they are very small, slender-looking insects with fringed wings. These insects are ideally found on flower petals or leaves. If you think that your plant is infested with thrips, then you can blow into the flower, and that will cause the thrips to move around. 

To identify thrips, take a closer look at the leaves, and if there are silver or speckled appearances on the leaves, then they are most likely infested by thrips. This also causes the leaves to weaken and fall off earlier. 

Thrips can cause significant damage to houseplants, but there are several steps you can take to remove them:

  • Isolation: If you notice thrips on one of your plants, first isolate the infested plant from your other plants to prevent the bugs from spreading.
  • Rinse the Plant: Thrips can often be dislodged by a strong stream of water. Take the plant outside or into a bathtub or sink and thoroughly rinse the plant with water.
  • Insecticidal Soap: Insecticidal soap is a safe and effective treatment for many types of pests, including thrips. Mix the soap with water according to the instructions on the bottle and spray it onto the infested plant, covering all surfaces.
  • Neem Oil: Neem oil is a natural pesticide that can be effective against thrips. Mix the oil with water according to the instructions on the bottle and spray it onto the infested plant.
  • Spinosad: Spinosad is a natural substance made by a soil bacterium that can be toxic to insects. It’s available in many home and garden stores and can be effective against thrips.
  • Beneficial Insects: If your houseplant is large enough or if you have an indoor garden, you could consider introducing beneficial insects that prey on thrips, like ladybugs or lacewings.
  • Systemic Insecticide: For serious infestations, you may need to use a systemic insecticide, which is absorbed by the plant and kills the insects when they feed on the plant’s sap. Follow the instructions on the product label for safe and effective use.
  • Repotting: If the infestation is severe and the above methods don’t seem to be working, you may need to consider repotting the plant. Remove as much of the old soil as possible and replace it with fresh, sterilized soil.

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 Caterpillars

Caterpillars are butterfly and moth larvae. They range in length from about 18 inches to 2 or more inches. Their color varies by species, but grey, brown, and green are common, as they have flecked and striped patterns. They can have smooth skin or spines, strands of hair or bumps on their bodies.

The presence of frass (fecal pellets) on leaves and under the plant is a good indicator that caterpillars are causing the damage.

Remove and destroy caterpillars and eggs. If the plants in the house are outdoors and more caterpillars feed, spray them with neem oil extract, spinosad or a substance called delta or lambda-cyhalothrin, cyfluthrin for one to two weeks to control them.

Caterpillars can be a nuisance on houseplants, particularly if they’re the type that eats leaves. Here are some ways to remove caterpillars from your houseplants:

  • Manual Removal: The most straightforward method is to manually remove the caterpillars. Put on some gloves and carefully pick them off your plants. You can then relocate them outside, far away from your houseplants.
  • Insecticidal Soap: Insecticidal soaps are safe for most plants and can effectively kill caterpillars. Spray your plants according to the instructions on the bottle, covering all plant surfaces.
  • Indoor Pesticides: Try insecticides that contain pinosad or a substance called delta or lambda-cyhalothrin, cyfluthrin for one to two weeks to control them.
  • Neem Oil: Neem oil is a natural pesticide that disrupts the life cycle of pests like caterpillars. Mix it with water according to the instructions and spray it on the affected plants.
  • Bacillus thuringiensis (Bt): Bt is a naturally occurring bacterium that’s toxic to many types of caterpillars but harmless to humans, pets, and beneficial insects. It’s available as a spray in most garden centers.
  • Beneficial Insects: Consider introducing beneficial insects into your indoor garden. Insects like ladybugs, lacewings, and certain types of wasps prey on caterpillars and can help keep their population under control.
  • Physical Barriers: If you know where the caterpillars are coming from, you might be able to use physical barriers to keep them away from your plants. For example, you could use sticky bands around the trunks of larger plants.

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Spider Mites

Mites are kin to spiders rather than insects. Because they are so small, you can only spot them if there is damage to your plant. If the infestation is severe, you can see a silky-smooth web. 

Spider mites, both adults and larvae, cause harm to plants by consuming plant sap. The damage is indicated by faded lining on the outer surface of the leaves, and the plant seems faded overall. In the case mites continue to thrive, the plant may wither, and the leaves turn yellow. These insects are more frequently linked with houseplants, in particular, the English Ivy and palm plants in other cases. 

Spider mites can be particularly difficult to control, as they reproduce rapidly and can develop resistance to pesticides. However, there are several steps you can take to combat an infestation:

  • Isolate the Infected Plant: First, if you notice spider mites on one of your plants, isolate it from your other plants to prevent the mites from spreading.
  • Rinse the Plant: Spider mites can often be dislodged by a strong stream of water. Take the plant outside or into a bathtub or sink and thoroughly rinse the plant with water.
  • Increase Humidity: Spider mites thrive in dry conditions, so increasing the humidity around your plants can help deter them. This can be done by misting your plants with water, placing a tray of water near your plants, or using a humidifier.
  • Insecticidal Soap or Horticultural Oil: Insecticidal soaps or horticultural oils, such as neem oil, can be effective against spider mites. Mix the soap or oil with water according to the instructions on the bottle and spray it onto the infested plant, making sure to cover all surfaces.
  • Predatory Mites: If the infestation is severe or the plants are particularly valuable, you might consider introducing predatory mites. These are mites that feed on spider mites and can be purchased online or at some garden centers.
  • Systemic Miticides: For serious infestations, you may need to use a systemic miticide, which is absorbed by the plant and kills the mites when they feed on the plant’s sap. Follow the instructions on the product label for safe and effective use.

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 Fungus gnats

Fungus gnat adults can be 1/8-inch in length and have a fragile appearance. They are frequently fluttering close to the soil under a houseplant. They are slow fliers who are attracted to light.

Although the adult fungus gnats may not consume houseplants, they can be troublesome. If the infestation is severe, they frequently appear in abundance in places such as large windows. Fungus gnats’ pale white larvae may have shiny black head. They may grow to be 14 inches long. The larvae feed on decomposing decaying matter or fungi found in the soil. Larvae of some species will also feed on roots.

Fungus gnat adults are about 1/8-inch in length and have a fragile appearance. They are frequently seen running across the ground or fluttering near it. They are poor flyers who are drawn to light. Although adults do not consume indoor plants, they can be a nuisance to humans. In severe infestations, they are frequently observed in huge numbers on nearby windows.

Fungus gnats are a common pest of houseplants in overwatered plants or in damp, organic-rich soils. Here’s how you can get rid of them:

  • Let the Soil Dry: Fungus gnats love moist soil. Allow the top 1-2 inches of the soil in your pot to dry out between waterings to discourage their reproduction. Avoid overwatering your plants.
  • Yellow Sticky Traps: Fungus gnats are attracted to the color yellow. Use yellow sticky traps to catch the adult gnats.
  • Diatomaceous Earth: This is a natural powder made from tiny fossilized aquatic organisms and can be sprinkled on top of your soil. It’s harmless to humans and pets, but lethal to insects, including fungus gnats.
  • Hydrogen Peroxide Solution: Mix one part 3% hydrogen peroxide with four parts water and water your plants with this solution. This can help kill the larvae in the soil.
  • Beneficial Nematodes or Hypoaspis Miles: These beneficial organisms can be added to your soil to kill fungus gnat larvae. They are naturally occurring and safe for your plants.
  • Insecticidal Soap or Neem Oil: These can be used to spray your plants and kill off any adult gnats. Make sure to cover the soil as well to kill any larvae.
  • Repotting: If all else fails, you might need to consider repotting your plant with fresh, sterile soil. Be sure to clean the roots and the pot thoroughly before repotting.

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Remember to continue to check your plants regularly after treatment to ensure that the pests do not return. If the plant does not improve or the infestation persists, you may need to discard the plant to protect your other plants.Also remember, it’s easier to prevent an infestation than to get rid of one. Monitor your plants regularly for signs of pests, don’t overwater, and make sure your plants are in a well-ventilated area.

Looking for more ways to keep insects and pests away from you treasured plants? Check out this guide about how to use other plants and natural methods as an ecosafe way to prevent unwanted insects.