ZZ plants, also known as Zamioculcas zamiifolia or aroid palms, are popular for a reason. Not only do these lovely evergreens add glossy texture and deep green color to your indoor garden, but they’re also one of the easiest houseplants to care for and are rich in meaning and symbolism. They tolerate a wide range of soil, light, and moisture conditions and rarely need fertilizer or repotting. Best of all, they’re resistant to most pests and diseases. Read on to learn about how to deal with common ZZ plant pests, diseases, and other problems.
Common ZZ Plant Pests & Diseases – The Essentials
ZZ plants have very few insect or disease problems. The most common problem is brown scale insects on their foliage. These pests can be removed with rubbing alcohol and cotton balls or swabs. ZZ plants may also get aphids, fungus gnats, or mealybugs. These can be treated with insecticidal soap or horticultural oil.
The Most Common ZZ Plant Pests and Diseases
1) Scale Insects
Scale insects are among the most common pests that may attack ZZ plants. These tiny insects are related to aphids and whiteflies, but they look very different. About the size of a pinhead, brown scale affix themselves to ZZ plant leaves and drink the sap.
While they drink, the insects grow a distinctive, scale-like covering that gives them their common name. You’ll usually find them on the underside of leaves. If left too long, scale may cause drooping or yellowing foliage, distorted leaves, foliage dieback, and leaf loss. In these instances, your may need to cut back or prune your ZZ plant.
Scale may also leave honeydew on leaves, a sticky substance leading to sooty mold fungus growth. Though the sooty mold itself doesn’t harm the plants, it can block light to the leaves, interfering with the photosynthesis process.
Treat scale by wiping the bugs away with 70 percent isopropyl alcohol or soapy water, using a soft toothbrush, cotton swabs, or cotton balls. Check and clean every few days to prevent re-infestation.
2) Blight
Though it’s not too common, southern blight may affect ZZ plants. In many cases, blight is caused by excess moisture trapped between leaves. High humidity levels, poor air circulation, and warm temperatures can make blight worse.
Blight may manifest as yellowing lower leaves that turn creamy yellow to brown. Over a few weeks, the lower part of the plant may take on a mushy appearance. In time, the roots and rhizomes may rot.
To treat blight, remove the affected leaves and ensure the soil is cleared of dead foliage and other matter. Every third time you water your ZZ plant, add a tablespoon of hydrogen peroxide to the water. Pour the water directly onto the soil. Ensure plants have proper air circulation and let soil dry between waterings to prevent blight.
3) Aphids
You might have aphids if you notice strange-looking yellow marks or spots on your ZZ plant’s leaves. Check the underside of leaves for these tiny green, brown or black insects. They’re tiny and blend in, so you may have to look very closely to see them.
Like scale, aphids feed on plant leaves, sucking the sap out of the foliage. This leads to distorted leaves, curled foliage, and stunted growth rates.
They may also excrete honeydew that can lead to sooty black mold. Treat aphids by wiping them off with soapy water or insecticide soap.
4) Mealybugs
Mealybugs also feed on your ZZ plant’s sap. These hairy, sticky bugs look like tiny white ovals attached to your plant. They love to feed where leaves attach to the stems and along the veins of leaves. Look for them in your plant’s crevices.
Mealybugs lead to stunted plant growth and lead to wilted, yellowing leaves. They excrete a powdery substance that can attract ants to your ZZ plants.
To treat mealybugs, wipe or spray leaves with soapy water or insecticide soap.
5) Whiteflies
Though its rare, your ZZ plant may experience a whitefly infestation. Whiteflies resemble gnats, but their snowy white wings easily identify them.
The adult whitefly feeds on plant foliage. Leaves may fade, turning a pale yellow or white.
Treat whiteflies with a mixture of 1 tablespoon liquid dish soap to 1 gallon of water. Spray the top and bottom of the ZZ plant’s leaves and let the mixture dry. Spray again every two to three days until the fly population dies off.
6) Mites
ZZ plants prefer dry soil. Unfortunately, dry, dusty soil may attract mites. Sometimes known as spider mites, these arachnids are small and difficult to see. However, they do leave webs around the plant’s leaves and stems.
Use a stream of lukewarm water to knock mites off of plants, then follow up by wiping leaves with a soft cloth. If the mites persist, you may try insecticidal soap or horticultural oil, or use a pesticide that contains pyrethrin or permethrin.
7) Fungus Gnats
Fungus gnats can enter your home in the soil ZZ plants grow in from the greenhouse. They often infest soil mixes and containers, where they feed on decaying organic matter.
While the adult flies can’t do much damage to your ZZ plant, they are annoying, as they multiply quickly and like to buzz around the home. In large numbers, though, the larvae can damage plant roots.
Treat fungus gnats by controlling moisture and organic matter in the soil. You can trap adult flies on small, yellow sticky traps that sit in plant containers. Placing chunks of raw potato on the plant’s soil attracts the larvae; remove, dispose of, and replace the potato chunks every few days to reduce larvae populations.
Pesticide and Insecticide Solutions
Horticultural Oil & Canola Oil
If you’re experiencing an infestation of pests with soft bodies (like mealybugs, aphids, or mites) oils offer a solution. Since these insects breathe through small holes on their bodies, the oil coats the insects and suffocates them.
Some oils alter the breeding and egg-laying cycle, too. Oils may be petroleum-based or plant-based, such as canola or neem.
Insecticidal Soap
Insecticidal soaps contain high levels of potassium salts. They kill soft-bodied insects by suffocating them, just like oils.
These soaps can also be used to get rid of honeydew and sooty mold. Dishwashing liquid and water can also be used.
Pesticides
If other, non-synthetic methods aren’t working, pesticides may offer a solution. Just keep in mind that pesticides can cause damage to pets and humans if they’re not used properly.
Sticky Traps
Sticky traps can offer a natural solution for fungus gnats and whiteflies. These small bits of sticky paper are yellow, which attracts flying insects, then traps them.
This type of pest control is easy to use. Simply place the stickers on spikes and place in the ZZ plant’s soil.
How to Use Pesticides & Insecticides for ZZ Plants
As with any houseplant, pest control should start with the least invasive method. For instance, start by spraying leaves with warm water, wiping with alcohol, or treating with horticultural oil, rather than jumping right into applying a synthetic pesticide.
No matter which method or product you choose, be sure to follow the directions carefully. That means knowing when and how to apply treatments; for instance, some treatments may work best at certain temperatures, some may require dry conditions, and others may require moist soil. Read precautions carefully before starting.
Remember, some treatments won’t work right away. Give the treatment time to work before reapplying. However, depending on breeding and egg-laying cycles, some treatments may need to be repeated until the infestation is under control.
Wear gloves when handling your ZZ plant and the pot. The plant’s sap contains calcium oxalate crystals, which can cause skin and eye irritation.
Managing Pests & Diseases
The best way to control pests and diseases is by creating optimal growing conditions for your ZZ plant. That means choosing the right soil mix: well-draining soil that’s never waterlogged. The proper watering schedule is vital, too, as ZZ plants can’t thrive if they’re overwatered. Additionally, you’ll want to be extra cautious with recently propagated ZZ plants. With due care and attention, ZZ plants can live for years.
The right amount of light helps keep ZZ plants solid and resistant to pests and diseases. Indirect or low-light conditions are best for ZZ plants. Finally, feed your ZZ plant twice a year, using diluted, balanced fertilizer during spring and summer.
Wrapping Up
ZZ plants aren’t susceptible to pests and diseases and tend to have very few problems. Their low-maintenance nature is one reason why Z. zamifolia is such as popular houseplant. With the right growing conditions, your ZZ plant will remain healthy and resilient.
If you’re looking for your next ZZ plant, see our in-depth guide to the best plant shops delivering ZZ plants nationwide.
Linsay is an American copywriter based in the Pacific Northwest with a background in academic writing and research. Linsay holds Master's degree in both Anthropology and Library and Information Sciences and has written for numerous national and international publications including USA Today, SFGATE, Hunker, and The Bump across an array of topics in the gardening, green living, and travel sectors. When she's not writing, you'll usually find Linsay reading, kayaking, sailing, snowboarding, or working in her garden.
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