What's Eating Your ZZ Plant?

Zamioculcas zamiifolia

Reviewed by Kiersten Rankel M.S.

Quick Answer

ZZ plants are one of the toughest houseplants, so the pest list is short. Mealybugs are the most insidious, hiding in the junctions where leaflets meet the central rachis. Scale insects cling as oval brown bumps on the smooth thick rachises. Fungus gnats are a warning sign that the soil is too wet for the rhizome.

Stay on top of plant care

Get seasonal reminders for watering and fertilizing, personalized for your plants.

Try Greg Free

What does the damage look like?

Tap the closest match to jump straight to the fix.

White cottony tufts in leaflet joints

›

Oval brown bumps on stems

›

Tiny black flies near the soil

›

Pests, ranked by impact

Mealybugs

Damage

High

Removal

Hard

What it looks like

Soft white insects coated in cottony fluff, 2 to 4 mm long. Tuck into the rachis-leaflet junctions where each pair of leaflets emerges from the central stalk. Slow-moving and easy to miss because the waxy glossy leaflets reflect light away from the colonies hiding in the joints.

What the damage looks like

White cottony specks lined up along the rachis where leaflets attach. A sticky shiny film on leaflets below the cluster. Leaflets yellow and drop one pair at a time. Severe infestations stall the plant and stop new rachises from emerging from the rhizome.

How to get rid of them

Option 1

Cotton swab dipped in 70% isopropyl alcohol

Dab every visible mealybug. The alcohol melts the waxy coating and kills on contact. Pull leaflet pairs gently apart to reach colonies tucked into each rachis-leaflet junction. ZZ plant's thick waxy leaflets handle the alcohol well. Repeat every 3 days for 3 weeks to catch newly hatched eggs.

Option 2

Insecticidal soap spray, weekly for 4 weeks

Spray ready-to-use insecticidal soap (Safer Brand, ~$10) on every rachis and into the leaflet joints at lights-out. Repeat every 7 days for 4 weeks because eggs hatch in protected joint pockets over time. The waxy leaflets shed soap residue easily, so reapplication matters.

Option 3

Isolate the plant from your collection

Move the ZZ plant at least 6 feet from other houseplants. Mealybugs spread by crawling. Wipe nearby pots, the windowsill, and any tools that touched the infested rachises.

Brown soft scale (Coccus hesperidum) clustered on a plant stem

Scale insects

Damage

Medium

Removal

Moderate

What it looks like

Oval brown bumps stuck to the smooth thick rachises and the underside of leaflets, 1 to 3 mm wide. Look like tiny barnacles glued in place. The smooth waxy surface of a ZZ rachis makes them stand out once you know to look.

What the damage looks like

Yellow patches around each bump on the rachis. A sticky shiny film along the stalk and on leaflets below the cluster, sometimes with sooty black mold. Heavy infestations cause leaflet drop and slow the rhizome's ability to push out new growth.

How to get rid of them

Option 1

Scrape and dab with alcohol, weekly for 3 weeks

Scrape every visible bump off the rachis with a fingernail or soft toothbrush. ZZ plant's tough waxy stalks tolerate firm scraping.

Dab any remaining bumps with a cotton swab dipped in 70% isopropyl alcohol to kill the insect under its waxy seal.

Repeat weekly for 3 weeks to catch newly hatched crawlers before they form their own protective shell.

Option 2

Horticultural oil spray, weekly for 3 weeks

Spray horticultural oil (Bonide All Seasons, ~$15) on every rachis and the underside of every leaflet. The oil smothers crawlers and adults. Apply at lights-out every 7 days for 3 weeks. The waxy leaflet surface tolerates the oil without burning.

Fungus gnats

Damage

Medium

Removal

Easy

What it looks like

Tiny dark flies, 1 to 3 mm long, hovering near the soil and flying up when you water. Larvae are barely-visible white worms in the top inch of damp soil. Their presence on a ZZ plant is a red flag, not a minor nuisance.

What the damage looks like

Adults are mostly a nuisance, but on ZZ plant they are a warning. Fungus gnats only thrive in damp soil, the same conditions that rot the rhizome. Rhizome rot is the number one killer of ZZ plants and is usually irreversible by the time the leaflets show damage.

How to get rid of them

Option 1

Stop watering and let the soil dry completely

ZZ plant stores water in its rhizome and tolerates a month or more without watering. Withhold water until the entire pot is bone dry, then wait another week. The dry soil kills larvae, stops adults from laying eggs, and saves the rhizome from rotting. Resume watering only when the rachises start to wrinkle.

Option 2

Yellow sticky traps near the soil

Stick yellow cards (Trappify, ~$10) just above the soil surface. Adults stick on takeoff and landing. Catches the breeding population while the dry-down kills the larvae underneath.

Option 3

Mosquito Bits sprinkled on soil

Mosquito Bits (Bt-i, ~$15) is a bacteria-based larvicide that kills fungus gnat larvae specifically. Sprinkle a tablespoon on the soil surface. The next time you do water (after the full dry-down), the active ingredient will release into the top layer. Safe for the ZZ rhizome and beneficial soil microbes.

Common myth

Drench the soil with hydrogen peroxide.

It kills larvae but it also adds liquid to the exact soil that's already too wet, which is the real reason gnats showed up. On a ZZ plant, the rhizome rots before you finish the treatment cycle. The only fix is letting the pot go bone dry.

Stay ahead of all of them

Three habits keep ZZ plant pests rare, plus the one watering rule that prevents the killer underneath.

Rachis-joint check, every other Sunday

Mealybugs and scale both hide where the leaflets meet the central rachis. A 30-second scan along each stalk every two weeks catches colonies while the ZZ is still pushing them off easily.

Quarantine new houseplants for 2 weeks

Mealybugs and scale travel home from the nursery on the plant you bought. Two weeks of isolation catches anything before it reaches your other houseplants, especially because ZZ pests rarely come from the ZZ itself.

Wipe the leaflets with a damp cloth monthly

ZZ leaflets are smooth, waxy, and hold dust beautifully. The wipe catches dust, early scale crawlers, and the first mealybug colonies before they multiply along the rachis.

Let the pot dry completely between waterings

ZZ plant stores water in its underground rhizome and rots fast in damp soil. Wait until the rachises just start to wrinkle, then water deeply. Dry soil prevents both fungus gnats and the rhizome rot they signal.

Stay on top of plant care

Get seasonal reminders for watering and fertilizing, personalized for your plants.

Try Greg Free

About This Article

Kiersten Rankel M.S.

Botanical Data Lead at Greg · Plant Scientist

About the Author

Kiersten Rankel holds an M.S. in Ecology & Evolutionary Biology from Tulane University. A certified Louisiana Master Naturalist, she has over a decade of experience in science communication, with research spanning corals, cypress trees, marsh grasses, and more. At Greg, she curates species data and verifies care recommendations against botanical research.

See Kiersten Rankel's full background on LinkedIn.

Editorial Process

Pest identification and treatment guidance verified against Zamioculcas zamiifolia field reports from Greg's botanical database, cross-referenced with university extension sources and published horticultural research.

48,211+ Greg users growing this plant

USDA hardiness zones 9b–13b

Citations:
NC State Extension
Missouri Botanical Garden
Mealybug photo: Gianni Del Bufalo (CC BY 2.0)
Scale photo: Whitney Cranshaw, Bugwood.org (CC BY 3.0 US)
Fungus gnat photo: B. Schoenmakers (CC BY 3.0)