Houseplants have become an important element in our modern world. They bring life, beauty, and a touch of nature into our busy lives, enriching our surroundings and nurturing our well-being. Bringing houseplants into our living and working spaces allows us to reconnect with nature on a daily basis. In addition to their aesthetic appeal, houseplants can purify the indoor air, remove airborne toxins, and have a positive effect on our mental health and productivity.
In general, most houseplants are not too difficult to care for. Depending on the specific species, houseplants need a stable environment with suitable temperature, humidity level, soil, and watering schedule. It is crucial that you inspect your houseplants regularly to check for signs of diseases, leaf and root problems, and one very important issue: pests!
Pests are a common concern when it comes to caring for houseplants. They can be detrimental to the health and vitality of our beloved green companions if not addressed promptly. Regular inspection and prompt action are essential to catch pest infestations early on and prevent them from spreading. Let’s take a look at the most common houseplant pests and treatment plans.
Spider Mite
Spider mites are incredibly small pests. They are not easily visible to the naked eye until their population has increased significantly or visible damage is already evident on the plants. Spider mites can vary in color depending on the species and life stage. They may appear green, yellow, red, brown, or even translucent. they produce fine silk webbing that can cover the infested areas. Spider mites feed on plant sap, they deplete the plant's vital fluids, leading to reduced vigor and weakened growth. Plants infested by spider mite often show stunted growth and reduced overall vigor.
Treatment:
- Isolate infested plants.
- Prune and dispose of severely infested leaves.
- Spray the leaves, paying close attention to the undersides where mites often gather. Strong water streams can remove mites and break up the webs. The increased humidity can also make the environment less favorable for spider mites.
- Homemade Remedies: Some home remedies may help control spider mites. Diluted neem oil, a solution of water and dish soap, or a mixture of rubbing alcohol and water can be sprayed on the affected plants.
- Use insecticidal soaps or oils specifically labeled for spider mite control.
- Repeat Treatments: Spider mite infestation may require multiple treatments to completely eliminate the pests.
- Move your plants outdoors for better sunlight and airflow can also help.
Mealybugs
Mealybugs are typically small, measuring about ⅛ to ¼ inch (3-6 mm) in length. They have a soft, oval-shaped body covered in a powdery or cottony white wax that gives them a distinct appearance. This white waxy material serves as a protective coating for both adult females and their eggs. Mealybugs often gather in clusters, especially on plant parts such as stems, leaf joints, and undersides of leaves. They feed by piercing plant tissue and extracting sap, which can weaken the plant and lead to stunted growth, yellowing leaves, and sometimes plant death. Mealybugs excrete a sticky substance called honeydew that creates a favorable environment for the growth of sooty mold fungi. If you notice a white, cottony substance on your houseplants or observe slow-moving, pale insects clustered on the plant, it is likely that you have a mealybug infestation.
Mealybugs is one of the most common pests on houseplants
Photo by Frederic Cerez
Treatment:
- Isolate infested plants.
- Manual Removal: For light infestations, you can manually remove mealybugs by gently wiping them off the plant using a cotton swab or a soft cloth soaked in rubbing alcohol. Mealybugs usually gather at leaf joints and the undersides of leaves.
- Use insecticidal soaps or neem oil extract to spray on the entire, including the undersides of leaves and stem crevices. Repeat the application as needed.
- Introduce natural predators such as ladybugs or predatory beetles to your plants. These beneficial insects feed on mealybugs and can help control their populations. You can purchase them from garden centers or online suppliers.
Aphids
Aphids are small, soft-bodied pear-shaped insects about 1/16– to ⅛-inch long. Aphids vary in color and can be green, black, brown, yellow, or even pink. Aphids feed on the sap of plants by piercing the plant tissues with their mouthparts. They prefer young, tender growth and often cluster on the undersides of leaves or at the tips of stems. As they feed, aphids can cause several types of damage, including stunted growth, distorted leaves, yellowing, and curling of leaves. Like mealybugs, they also excrete honeydew, a sugary substance that can attract ants and promote the growth of sooty mold. If you observe a high presence of ants around your plants, it may indicate the presence of aphids as well.
Treatment
The treatment plant for aphids is similar to the one for mealybugs above. You can also add try another solution: horticultural oil. This oil, like mineral oil or dormant oil, can smother aphids and their eggs. These oils should be applied during the dormant season or when plants are not in direct sunlight to avoid leaf burn.
Fungus gnats
Fungal gnats are one of the most irritating pests because they are very difficult to get rid of. These gnats are between 1/16 to 1/8 inch long, black or greyish, and have translucent wings. Fungal gnats tend to lay smooth ovular eggs that are translucent white. When checking the soil for signs of activity, keep an eye out for the small, white eggs or cocoons in the soil. Fungus gnats are commonly found indoors when potting soil rich in organic matter, such as peat moss, is used for growing plants. Overwatering can contribute to the problem as it creates a favorable environment for fungus gnats to thrive. The larvae typically feed on decaying organic material or fungi present in the soil. Some species of larvae also feed on plant roots, but adult fungus gnats do not feed on houseplants. They are not especially dangerous, but primarily a nuisance to people due to their presence. However, their abundance can be an indicator of an underlying issue with the plant's soil. The soil may be waterlogged or have too much decaying matter.
Treatment
- Check if the soil is waterlogged or has decaying matter. Remove all dead leaves.
- Allow the soil to dry out between waterings to discourage fungus gnat larvae growth.
- Avoid overwatering and ensure proper drainage in your plant pots.
- Use sticky traps or yellow sticky cards to capture adult fungus gnats and monitor their population.
- If necessary, apply an insecticide specifically labeled for fungus gnat control. Follow the instructions on the product carefully.
Scale Insects
Scale insects are divided into two primary groups: armored scales and soft scales. Armored scales have a protective waxy covering that can be scraped off to expose the insect beneath. On the contrary, soft scales have a waxy covering that is an integral part of their structure. Adult scales are small, immobile insects without visible legs. They may resemble flat, fish-like scales adhering to plant surfaces, while others appear as colored waxy masses. Scales can range in size from 1/16 to 1/2 inch in diameter. The immature forms of scales are mobile and feed by sucking plant sap. Similar to mealybugs, soft scales excrete honeydew that can lead to the growth of black sooty mold on foliage and stems. Scales feed by piercing the plant tissue and extracting sap, depriving the plant of essential nutrients. As scales feed, they weaken the plant and can cause symptoms such as stunted growth, yellowing leaves, leaf drop, and an overall decline in plant health.
Treatment
Treatment for scale insects is similar to the one for mealybugs and aphids above. In addition to neem oil extract, you can also try canola oil.
Whiteflies
Whiteflies are extremely small insects, measuring approximately 1/10 to 1/16 inch in length. They have white, powdery wings. the immature stage of whiteflies is scale-like. When disturbed, whiteflies will flutter around for a brief period before settling again on the plant. Whiteflies feed by piercing plant tissues and extracting sap, similar to other sap-sucking pests. They primarily target the undersides of leaves, where they cluster in large numbers. As they feed, they also excrete sticky honeydew that facilitates the growth of sooty mold fungi. The damage caused by whiteflies includes yellowing and wilting of leaves, stunted growth, and overall weakening of the plant.
Treatment
- Physical Removal: Gently shaking or using a jet of water to dislodge whiteflies from the plant can help reduce their numbers.
- Insecticidal Soap or Oil: Applying insecticidal soap or horticultural oil to the affected plants can suffocate and kill whiteflies. Repeat applications may be necessary.
- Biological Control: Introducing natural predators, such as ladybugs, can help control whitefly populations.
- Yellow Sticky Traps: Placing yellow sticky traps near infested plants can help monitor and capture adult whiteflies.
- Insecticide imidacloprid: Applying imidacloprid granules to the soil can provide systemic control of whiteflies.
Caterpillars
Caterpillars are the larval stage of butterflies and moths. They are well-known pests in gardens and can also be a problem for houseplants, especially if planted outdoors. Caterpillars vary in size, shape, and color depending on the species. They typically have soft bodies with distinct body segments and are often covered in fine hairs, spikes, or bumps. Caterpillars are voracious eaters and primarily feed on plant foliage. After hatching from eggs, they continuously eat and grow until they reach their full size. They have strong jaws that can produce significant damage to plants. They can cause holes in leaves and can eat a huge part of the foliage in your plants, making it difficult for your plants to photosynthesize.
Treatment
- Hand-pick, remove, and destroy any caterpillars and eggs that you find. Carefully check both the upper and lower surfaces of leaves and stems.
- Natural Predators: Encourage natural predators such as birds, spiders, or beneficial insects like ladybugs or lacewings to control caterpillar populations.
- Biological Insecticides: Bacillus thuringiensis (Bt) is a commonly used biological insecticide that specifically targets caterpillars.
- Sprays your plants with neem oil extract can provide some control against caterpillars.
Snails and slugs
Snails and slugs are nightmares for outdoor gardeners. These pests are mostly found outdoors, but they can also enter indoor spaces through open doors or windows. They have soft bodies and no legs with a slimy texture and move by gliding on a muscular foot. Snails typically have a coiled shell on their back, while slugs lack a visible shell. Snails and slugs feed on plant leaves, stems, and other soft plant parts. They leave behind irregular holes or chewed edges on the foliage, which can affect the overall appearance and health of the plants.
Treatment
- Handpick: Check your plants during the evening or early morning when snails and slugs are most active. Handpick them off the plants and dispose of them in a sealed container or relocate them away from your garden.
- Barriers: Create physical barriers around your plants to prevent snails and slugs from reaching them. This can be done by placing copper tape or abrasive materials like eggshells or pebbles around the plants. These substances create an unpleasant sensation for the pests and deter them from climbing up.
- Beer traps: Set up beer traps by burying shallow containers or lids in the soil near the plants. Fill the containers with beer, which attracts snails and slugs. They will crawl into the containers and drown. Empty and refill the traps regularly.
- Deter slugs and snails from your garden with herbs and plants that they dislike: rosemary, mint, fennel, thyme, sage or lavender.
- Natural predators: Invite natural predators such as birds, frogs, ducks and hedgehogs to your garden.
Last Note
In conclusion, controlling pests in houseplants requires a proactive approach and consistent monitoring.
- Regularly inspect your houseplants for signs of pest infestations, such as damage to leaves, the presence of insects, or unusual discoloration. Catching pests early can prevent them from spreading and causing further damage.
- Maintain good plant hygiene by removing dead leaves, debris, and fallen plant material. This reduces hiding places and eliminates potential food sources for pests.
- Create a healthy environment for your houseplants by providing proper lighting, watering, and appropriate potting soil. Healthy plants are more resistant to pests and can better withstand infestations.
