What's Eating Your Venus Fly Trap?

Dionaea muscipula

Reviewed by Kiersten Rankel M.S.

Quick Answer

For Venus fly trap, the pest list is unusually short because the snap-traps catch most attackers as food. Fungus gnats are the main worry. They breed in the constantly damp sphagnum and signal anaerobic substrate that rots the rhizome. Spider mites turn up in winter dry indoor heat and feed on leaves the traps can't catch. Aphids occasionally cluster on the spring flower stalk.

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.

Tiny black flies near the soil

›

Tiny pale dots and webs

›

Green clusters on the flower stalk

›

Pests, ranked by impact

Fungus gnats

Damage

Medium

Removal

Easy

What it looks like

Tiny dark flies, 1 to 3 mm long, hovering above the sphagnum and lifting off when you tray-water. Larvae are barely-visible white worms wriggling in the top of the wet peat. Traps catch some adults but never enough to control a real population.

What the damage looks like

Adults are mostly a nuisance, but their numbers are a warning. Venus fly trap needs constantly damp nutrient-poor sphagnum or peat, which is also ideal gnat habitat. Heavy gnat populations mean the substrate is going anaerobic, which rots the rhizome at the soil line and kills the plant from the base up.

How to get rid of them

Option 1

Refresh the sphagnum or peat substrate

Lift the plant out and rinse the rhizome gently in distilled or rainwater. Look for any soft brown rot at the base.

Repot in fresh long-fiber sphagnum or a 1:1 peat and perlite mix. Never use regular potting soil. Fertilizer kills Venus fly trap.

Resume tray-watering with rainwater or distilled water only. Tap water minerals build up in the substrate and kill the plant over months.

Option 2

Yellow sticky traps just above the substrate

Stick yellow cards (Trappify, ~$10) right at the rim of the pot. Adults stick on takeoff and landing. Catches the breeding population while the substrate refresh kills the larvae. Replace every 2 weeks.

Option 3

Mosquito Bits sprinkled on the substrate

Mosquito Bits (Bt-i, ~$15) is a bacteria-based larvicide that targets fungus gnat larvae specifically. Sprinkle a teaspoon on the sphagnum surface. Safe for the plant and won't add minerals or nutrients that would harm a Venus fly trap.

Spider mites

Damage

Medium

Removal

Moderate

What it looks like

Almost invisible without a hand lens. Yellow-green to red-orange specks running along the trap lobes and the flat green leaf bases. Mites are far too small to spring a snap-trap, so the plant's catching mechanism gives no protection here. Most often appear in winter when indoor heating dries the air.

What the damage looks like

Pale tiny pale dots along the trap lobes and leaf bases, with fine webbing strung between the trigger hairs. Heavy feeding bronzes the lobes so they no longer close cleanly. The damage is on the leaves themselves, not the prey, which is what makes spider mites unusual on this plant.

How to get rid of them

Option 1

Shower the leaves with rainwater or distilled water

Move the plant to the sink and spray cool rainwater or distilled water on every trap and leaf base for 30 seconds. Never use tap water. The rinse knocks mites off and they can't reattach quickly. Repeat weekly for 3 weeks. Avoid soap, oil, and neem on Venus fly trap. The leaves are extremely sensitive.

Option 2

Raise humidity above 50%

Run a humidifier near the plant for 50 to 60% relative humidity. Venus fly trap is a wetland plant from coastal Carolina bogs and wants the moisture anyway. Hot dry indoor heating in winter is the climate mites breed fastest in.

Option 3

Move the plant outside for the warm months

Venus fly trap thrives outdoors in zones 7 to 10 and is happier in full sun on a tray of rainwater than on any windowsill. Outdoor predators (real predatory mites, lacewings) usually clear a spider mite population within a few weeks at no cost.

Aphids

Damage

Low

Removal

Easy

What it looks like

Soft pear-shaped insects 1 to 3 mm long, usually pale green, clustering on the tall spring flower stalk and occasionally on new leaf bases. Aphids weigh too little to trip the trigger hairs of a snap-trap, so the plant's catching mechanism doesn't help. The natural prey of Venus fly trap is heavier insects like flies, gnats, ants, and small spiders.

What the damage looks like

Curled or distorted new growth on the flower stalk and the youngest leaf bases. A faint sticky shine where aphids have fed. Mature traps are rarely affected. The flower stalk takes most of the damage, which mainly costs you the bloom that spring.

How to get rid of them

Option 1

Knock them off with a rainwater spray

Aim a firm spray of rainwater or distilled water at the flower stalk and any clusters on leaf bases. Aphids dislodged this way rarely climb back. Never use tap water on Venus fly trap. The minerals build up and damage the plant over time. Repeat every 3 days for 2 weeks.

Option 2

Wipe the flower stalk with a damp cotton swab

For small clusters, run a cotton swab dipped in rainwater along the flower stalk. Crushes the colony directly. Skip soap, oil, and alcohol. Venus fly trap leaves and stalks are extremely sensitive to surfactants and oils that other houseplants tolerate.

Option 3

Cut the flower stalk if the plant is young

Most Venus fly trap growers cut the spring flower stalk anyway. Flowering takes huge energy from a small plant and the trap-growing season is more rewarding. Cutting the stalk also removes the aphid colony in one snip.

Common myth

Feed your Venus fly trap raw hamburger.

Venus fly trap digestion is built for insects and small spiders. Mammal meat rots in the trap before the plant can break it down, turns the lobe black, and the trap dies and falls off. Feed the plant only live or freshly killed insects, or simply let it catch its own prey outdoors.

Stay ahead of all of them

Four habits that keep Venus fly trap pests rare and the plant thriving.

Rainwater or distilled water only

Tap water minerals build up in the sphagnum and kill Venus fly trap over months. Catch rainwater in a bucket or buy distilled by the gallon. This single habit prevents more dead plants than any pest treatment.

Tray-water and refresh the substrate yearly

Keep the pot in a half inch of rainwater at all times during the growing season. Repot in fresh long-fiber sphagnum or peat-perlite each spring. Old substrate goes anaerobic, which is what builds fungus gnat populations and rots the rhizome.

Move the plant outside from spring to fall

Venus fly trap is a coastal Carolina bog plant that wants full sun and outdoor air. Outdoors the plant catches its own prey, real predators handle most pest pressure, and humidity stays naturally high. Indoor cultivation is harder for the plant and the grower.

Skip every soap, oil, and synthetic feed

Insecticidal soap, neem oil, and any fertilizer kill Venus fly trap. The plant evolved in nutrient-poor bog soil and gets nutrients from the insects it catches. If a pest needs treatment, the answer is a water rinse or substrate refresh, never a spray.

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 Dionaea muscipula field reports from Greg's botanical database, cross-referenced with university extension sources and published horticultural research.

15,504+ Greg users growing this plant

USDA hardiness zones 6a–11b

Citations:
NC State Extension
Fungus gnat photo: B. Schoenmakers (CC BY 3.0)
Spider mite photo: Clemson University - USDA Cooperative Extension, Bugwood.org (CC BY 3.0 US)
Aphid photo: Scot Nelson (CC0)