In my experience, peace lily plants (Spathiphyllum) can be affected by root rot due to overwatering or a viral mosaic disease on the leaves. Common pests include thrips, mealybugs, aphids, and spider mites. Fungus gnats are also common due to the high demand for water from this plant. Knowing what to look for is key with the Peace Lily because these plants may not show any obvious signs of infection or infestation until serious damage occurs. Tackle peace lily pest and disease problems head-on with this popular houseplant.
Common Peace Lily Pests and Diseases
Peace Lily plants are susceptible to only a few diseases, unlike some houseplants. This means you just need to watch for serious signs of damage to know if something’s infecting your plant. For pests, the problems are a little more widespread.
Many pests that frequent indoor Peace Lily plants are easy to overlook due to their small size or habit of hiding. Pest control methods include wiping down the leaves once a month will remove dust and help you check for pests and early signs of disease. Treatment is much easier when pests are caught early rather than after they spread to all of the leaves.
The main disease affecting Peace Lily plants is root rot. It can be caused by a number of different fungal or bacterial infections, but you don’t need to identify the specific cause to treat it.
Root rot sets in when the Peace Lily is kept too wet. They do require steady watering but don’t want to be watered daily and need to dry out between water applications. Many people make the mistake of giving them water too often and won’t let the soil at the very bottom of the pot get dry.
Root rot causes symptoms like failure to grow, loss of random leaves throughout the plant, and yellowing in the new leaves. When you lift the plant from the pot, you may see black or brown roots that are mushy to the touch. Only trimming off the rotten roots and letting the soil dry out can treat the problem. You’ll also need to consider repotting your peace lily in fresh soil.
This is a relatively uncommon viral infection that can spread between Peace Lily plants and other affected species. Once a plant becomes infected, new leaves may show a mottled pattern of light color over the usual dark green shade.
Many leaves may grow out with no sign of infection at all. It’s impossible to treat a plant with this virus. If you don’t have any other houseplants, you may choose to just keep the Peace Lily and let it grow. If you have other plants, it’s best to destroy the plant before it can spread the virus to the rest of them.
Some of the smallest pests that attack Peace Lily plants are common aphids. They’re found in landscapes and gardens worldwide, so it’s easy for them to get inside and settle on your houseplants. They’re tiny and look like white, red, or gray dots moving around on a leaf’s underside.
The only way to honestly tell if you’re dealing with aphids or another small pest is to check one of them with a magnifying glass. Aphids have two tiny protrusions from their rear end that look almost like large antennae.
They’re all treated similarly, with a combination of physical removal and pesticide treatment offering the best pest control for most houseplant owners.
Mealybugs are fuzzy or almost fluffy looking. They’re small insects that move around the stems and leave cotton-looking masses on them. You may find sticky deposits of honeydew, a clear substance expelled by the insects.
This honeydew can trigger the growth of black deposits known as sooty mold. Aphids can also cause honeydew and sooty mold issues, so check for the fuzzy appearance of the mealybugs to determine which pest is the problem.
One of the hardest insects to notice is the scale. As its name suggests, these insects resemble a scale like you’d find on a snake’s back. They may seem like just a brown or black spot on the leaf, but they’re actually an insect sucking sap right out of the leaf. The scale’s shape and appearance are designed to help it go without detection and to make it hard to remove. Looking for new dark spots that weren’t there in the weeks before is the key to catching scale when they move in.
Tiny mites crawling all over your Peace Lily aren’t likely to be spotted by the eye alone. It’s the cobweb-type webbing that they leave over the surface of the soil and hanging between stems. You may catch a few of the tiny mites and think they’re baby spiders, but they’re actually mites that can weaken the health of the plant. Don’t wait until leaves are yellowing or dropping to determine if you’re dealing with this pest or not. Treat early and often if you think you might be dealing with spider mites.
Thrips aren’t much bigger than mealybugs, but they tend to be easier to see than spider mites or aphids. They’ll jump around when disturbed like a tiny cricket or grasshopper might. You’ll notice little specks of damage on the leaves where thrips have been biting. Mature leaves may pucker up or twist due to the damage. Once the feeding covers an entire leaf, it may lose color and start browning.
Fungus gnats don’t threaten the health of the plant in most cases, but they’re annoying to have flying around your home. Letting the top of the soil dry out more between water applications is usually all you need to do to solve the problem.
Pesticide and Insecticide Options and Solutions
For most of the pests that affect Peace Lily plants, you can choose between storebought products and homemade solutions. All of the pests listed above are susceptible to being removed by hand. That’s the most organic and natural way to control insects, but it will require a daily commitment until the pests are under control. If you can’t spot the insects to remove them or aren’t even sure what pest you’re dealing with, trying a pesticide treatment may work better.
Horticultural Oil & Canola Oil
Canola oil from the grocery store is an inexpensive and homemade remedy for most insects. It’ll smother small insects like thrips, aphids, and more when applied on a daily basis. For a more targeted approach, try a horticultural oil from a garden supply store. These thin oils won’t block light transmission but work well on insects.
Some horticultural oils can be used to disrupt the breeding and egg-laying cycle. Such oils may be petroleum-based or plant-based, such as canola and neem.
The opposite approach is to use soap to cause the insects to flee due to the foam that soaks in the joints of their exoskeletons. Dish soap mixed with some warm water will work, but insecticidal soap is less likely to risk damage to the Peace Lily itself. It’s also slightly more effective on most insects that threaten this plant. Soaps work best on aphids, mealybugs, and mites. It won’t help much with scale.
Insecticidal soap offers a way to clean powdery mildew, sooty mold, and honeydew from plant foliage. You can use dish soap, too, but it doesn’t work quite as well.
Pesticides are the best solution for scale or extensive infestations of any other pests. Ensure the product is listed as safe for houseplant and indoor use and approved for use on Peace Lily plants. Peace Lily plants can be damaged by strong pesticides, but there are many organic products, in particular, that won’t risk damage to the leaves.
Generally, it’s best to try non-synthetic methods of pest control — like handpicking, water sprays, oils, and soaps — first. That’s because pesticides can damage plants, pets, and even humans if they’re mis- or overused.
But if non-synthetic methods aren’t working, there are multiple classes of pesticides, including carbamates, organophosphate, and pyrethroids.
Sticky traps help control fungus gnats in particular, but they can help with spider mites as well. Try placing yellow sticky cards around the base of the plant to stop crawling insects from moving from stem to stem.
Most come with spikes so that you can place the sticky trap in the soil next to your Anthurium.
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How to Use Pesticides & Insecticides for Peace Lily Plants
Spraying the Peace Lily plant with a pesticide or insecticide takes a little effort due to the number of stems and leaves packed into one area. Separate the foliage into quarters and focus on soaking or spraying it one section at a time. Apply at the intervals listed on the product to ensure pests can’t just return when there’s a break in treatment.
Also, it’s worth noting that peace lily plants are considered toxic to both humans and pets so it’s prudent to wear gloves when handling these plants.
Managing Pests & Diseases
Keeping Peace Lily plants in environments where humidity is high enough will prevent many pest problems. Don’t overwater, even if the plant seems to struggle to keep enough moisture to prevent drooping. Make sure you position your peace lily plant in a location that provides sufficient light exposure as well (recently propagated and variegated Peace Lily plants can be particularly susceptible to light).
Switch to a better Peace Lily soil mix that holds some moisture so wilting isn’t so dramatic and fertilize and prune periodically in spring and summer. Healthy plants are less likely to attract pests, so focus on good care rather than constant pesticide use.
The Final Word
A Peace Lily can provide many years of beauty with minimal pest and disease issues. Act quickly if you do suspect a problem to avoid damaged and lost leaves. For more, see our ultimate guide to Peace Lily plant care at home and how big and how fast peace lily plants grow under optimal environmental conditions.