Whiteflies

Recognize the signs

Adults and nymphs

White winged adults lift off when leaves move. Flat, oval immature stages remain on the underside; their presence helps distinguish an infestation from a passing insect.

Damage

Honeydew, sooty coating and yellowing can accompany heavy feeding. These signs also have other causes.

Differences that change the decision

A similar-looking organism can need a different response. Compare the evidence and what it changes.

Compare every column. On a narrow screen, scroll the table sideways.

What else could it be?

Mealybugs and scales

Wax-covered bodies or attached covers can resemble whitefly immatures; check for white flying adults and examine several stages.

Compare scale & mealybugs ↗

Tiny flies from wet potting mix

Fungus gnats usually arise from soil and are dark, mosquito-like flies rather than white leaf colonies.

Compare small flies ↗

Inspect the right places

1. Check both leaf ages

   Turn over younger and older leaves on affected plants and nearby purchases. Record adults, immature stages and sticky deposits separately.

2. Use traps as a signal

   Yellow sticky cards can reveal flying adults, but catches alone do not measure all nymphs on a plant or prove species. Keep records tied to the same location.

Choose a proportionate response

For pesticides, the local product label determines the allowed pest, site, precautions and timing. Check safety and regional guidance.

1. Isolate and reduce early infestations

   Separate an affected movable plant. Remove a limited number of heavily infested leaves or wash sturdy foliage, then inspect remaining undersides.

2. Protect biological control

   Reduce dust and ants and retain predators. Commercial parasitoids need the correct whitefly, temperature and greenhouse setting; buying insects is not an automatic outdoor cure.

3. Escalate selectively

   For continuing damage, ask for a locally suitable, plant-labelled option. Contact sprays require access to the feeding sites and can injure sensitive foliage; follow plant, heat and harvest restrictions.

Avoid these mistakes

• Do not judge success only by adult clouds; hidden nymphs can remain.
• Do not use broad insecticide sprays by default; killing natural enemies can worsen the problem.
• Do not identify parasitised nymphs by darkness alone: some healthy species are dark.

Check whether it is working

Prevent a return

• Examine plant undersides before purchase and before bringing outdoor plants indoors.
• Keep plants healthy without excess fertilisation and preserve beneficial insects.

Common questions