Whitefly identification & organic control
Bemisia tabaci / Trialeurodes vaporariorum
How to identify whitefly
Tiny (1/16 inch) triangular white moths that flutter up in clouds when you brush the plant. Both adults and nymphs feed on the underside of leaves and coat them in sticky honeydew.
Crops attacked by whitefly
Tomato, Pepper, Eggplant, Bean, Cucumber, Kale.
Sap-sucking causes yellow stippling and leaf drop. Honeydew grows sooty mold and blocks photosynthesis. Some whiteflies transmit viruses (TYLCV in tomatoes).
Life cycle
- Egg (5-10 days) — Tiny yellow cones on leaf undersides.
- Nymph (4 instars) — 'crawler' then sessile (2-3 weeks) — The main feeding stage; fixed to the leaf, scale-like.
- Adult (1-2 weeks) — Flies to new leaves, lays eggs, spreads viruses.
Natural, organic whitefly control
- 1. Yellow sticky traps · low effort
Hang at plant height near affected leaves. Catches adults faster than any spray.
When: First sighting
- 2. Handheld vacuum in the morning · medium effort
Adults are sluggish in the cool morning. Vacuum them off leaf undersides; empty into soapy water.
When: Daily during outbreak
- 3. Insecticidal soap on undersides · medium effort
Spray leaf undersides at dusk every 5-7 days for 3 rounds to catch each new hatch.
When: Established infestation
- 4. Release Encarsia formosa (parasitic wasp) · medium effort
Standard greenhouse biocontrol — parasitizes whitefly nymphs. Works outdoors in warm, humid conditions.
When: Heavy infestation
Fastest-fix products
- Yellow sticky traps (10-pack) — Cheapest, fastest way to knock adult populations down. · Amazon
- Handheld cordless vacuum — Non-toxic removal of adults; unmatched for greenhouse and tunnel crops. · Any hardware store
- Safer Brand Insecticidal Soap — Kills nymphs on contact without residual harm. · Garden centers, Amazon
Prevention
- Inspect nursery transplants — whiteflies almost always arrive with new plants.
- Silver reflective mulch confuses adults looking for a landing site.
- Avoid excessive nitrogen; tender growth invites outbreaks.