Mealybugs, scale, spider mites, bacterial leaf spot, root rot, and anthracnose can all affect monstera plants. In my experience, various methods can address these issues, including insecticides, horticultural oil, and repotting. However, Monstera pests and diseases are best prevented with an optimal growing environment and suitable pest control solutions. In this guide, we’ll cover the most common types of Monstera plant pests, bugs, and diseases and essential tips to eliminate them.
A common indoor plant pest, mealybugs have white, oval-shaped, waxy bodies and a tail at one end. They also lay white clusters of eggs that you can find in the grooves and crevices of your plant.
As mealybugs feed on plant sap, they stunt growth and cause yellowing or brown spots on your monstera plant. Eventually, they can kill a plant.
To address mealybugs, isolate infected plants. Using a cotton swab, either use an insecticidal houseplant soap to wash away and kill the pests or remove and dispose of them (and their eggs) by hand.
Spider mites are tiny and difficult to see with the naked eye. Usually, the first sign of spider mites that you’ll notice is the whispy webs they create to navigate between different parts of your monstera plant while they feast on the plant’s chlorophyll. As they drain leaves of chlorophyll, you’ll start to notice small white spots or stippling on the foliage.
You can wash off mites using water or insecticidal soap formulated for houseplants. When dealing with spider mites, pay careful attention to the underside of the plant’s leaves.
Soft scale are a common pest problem with houseplants, including monstera plants. Scale insects can vary in color, but they are primarily brown or beige, and they look like tiny bumps on the foliage and stems of plants. Symptoms of scale include yellowing foliage and stems in addition to stunted growth and drooping monstera leaves.
Heavily infested plants should be discarded or, at the very least, carefully quarantined from other plants in your home. Use a horticultural oil or spray formulated for use on houseplants. You can also remove and kill insects using a cotton swab and alcohol.
Aphids feed on the new growth of monstera plants because the older foliage can be too tough for their teeth to sink into. These small, pear-shaped insects can be green, white, yellow, black, brown, or red in color. They eat plant sap and produce large amounts of a waste product called honeydew. This leads to sooty mold infestations on leaves.
Aphids can be addressed by simply washing them off the plant with water, insecticide for houseplants, or insecticidal soap. They can also be mitigated by introducing a natural predator, the ladybug, into your plants.
Whiteflies look like what you’d imagine; they’re little gnat-sized flies that are all white in color. They feed on the sap of houseplants, stunting growth and producing honeydew that can put your plant at risk of mold and fungal infections.
You can remove whiteflies from plants using lots of different methods such as vacuuming them off the plant, washing them off with water, using sticky traps, applying insecticidal soap, or with neem oil.
These tiny flies commonly infest and lay their eggs in potting soil and other types of potting media where plants grow. While they mainly feed on the organic matter in the soil, they can also eat plant roots, which can damage and weaken the plant.
To eradicate fungus gnats, you can try using sticky traps, but these don’t always completely solve the problem. It’s best to remove your plant from its pot and gently wash its roots before repotting in fresh a potting medium.
The term “leafminers” refers to several different plant pests, such as certain moth larvae, that burrow into plants and feed within their foliage, leaving behind tunnel injuries that scar the plant. These can look like trails, splotches, or blotches on the leaves.
The best solution for ridding a plant of leafminers is to use an insecticidal spray that has been specifically formulated to address leafminers. This spray will permeate the surface of your plant’s leaves where the pests are located.
Bacterial Leaf Spot
Bacterial leaf spot is a disease that produces similarly sized, yellow-rimmed, dark-brown spots on leaves that usually ooze a sticky substance. The bacteria spread through water and moisture on a monstera’s leaves.
Lowering humidity, increasing airflow, not grouping separate plants closely together, and refraining from misting the leaves can prevent the bacteria from spreading throughout the plant. You can also use sterile pruning shears to remove infected leaves from the plant.
Anthracnose is a fungal disease that commonly affects monstera plants living in an overly moist environment. Additionally, dead plant matter can increase the risk of developing anthracnose.
Infected plants develop yellowing Monstera leaves along the edges. This eventually progresses, turning into a tan or dark-brown color. Symptoms eventually spread inward, killing whole leaves and causing large sores or lesions on the stems.
Anthracnose is best prevented by managing the humidity level around plants, refraining from misting leaves, keeping plants free from decaying plant matter, and avoiding wounding the foliage.
Root and Stem Rot
Root and stem rot are bacterial infections that occur in monstera plants with too much moisture in and around their potting soil.
The condition is common in overly watered plants, containers that do not drain well, and plants whose potting mix holds too much moisture.
Signs of root and stem rot include significant wilting, soft or mushy stems, and brown or black roots in color with a mushy texture. You might also notice a foul smell coming from your plant’s soil.
When addressed early enough that the bacteria hasn’t spread to the plant’s stem, root rot can sometimes be managed by uprooting the plant, removing the diseased roots, washing the roots, and then repotting your monstera plant in a well-draining container.
Pesticide and Insecticide Options and Solutions
Horticultural oils (via Amazon) are usually vegetable or petroleum-based and diluted before spraying on a plant’s surface to control insects like spider mites and mealybugs.
Insecticidal soap is made using fatty acids and/or potassium salts. It’s designed to be plant-safe but lethal to houseplant pests.
Plant pesticides, often made with neem oil, are designed to kill certain pests and diseases like fungal infections.
Many variations of sticky traps (via Amazon), or flypaper, are available. These usually attract insects with a sweet scent and trap them when they land on or crawl over the sticky surface.
Regular dish soap can prove an effective pest remedy for houseplants – whether you’re washing your plant’s leaves to remove insects or making a fly trap with a dish of soapy water. Just be careful not to spill soap onto the plant’s soil.
How to Use Pesticides and Insecticides
A wide range of pesticide and insecticide products designed for houseplants are available on the market. For safety and effectiveness when using these, it’s essential to always read the use instructions and precautions on each product before using them.
These products are usually best applied to houseplants using a small misting bottle. Lay down a protected tarp and spray your plants in a location where chemicals can be easily cleaned up and will not wind up falling on other surfaces of your home.
Always wash your hands after use, store these chemicals safely according to their instructions, and never use them near an open flame or food.
Protective gloves will shield your skin from the monstera’s sap, which can cause irritation and a rash.
Managing Pests and Diseases in Monstera Plants
The best way to prevent pests and diseases in your monstera plant is to take proper care of it. A healthy plant has natural defenses to protect it and an environment that is not conducive to pests or diseases. Provide your Monstera plant with a well-draining container, appropriate Monstera soil mix, suitable light exposure, and occasional fertilizer, and avoid overwatering.
Additionally, keep new houseplants in quarantine away from your healthy plants until you are certain they are free of pests and diseases. Pruning and cutting back old Monstera growth can also make your plant more robust and ensure you position your monstera plants in a suitable location in the home.
A Healthy, Happy Monstera
With the right care, your monstera plants will thrive indoors, providing you with decades of enjoyment as you watch them grow and mature into fully fenestrated plants.
For more on the famed Monstera plant and to learn more about how to grow and care for these plants at home, please see our guide to the best Monstera varieties to grow at home.