Greenhouse Whitefly

Trialeurodes vaporariorum

1. Identification

• Common name: Greenhouse whitefly
• Scientific name: Trialeurodes vaporariorum Westwood
• Order: Hemiptera
• Family: Aleyrodidae

2. Pest description

• Adults: small winged insects (1–1.5 mm), pale-yellow body and white wings covered with powdery wax; slow, short flight.
• Nymphs: flattened, oval, translucent; they adhere firmly to the underside of the leaves.
• Pupa (4th instar): oval structure, thicker and opaque, with slightly raised margins.
• Eggs: oval, initially whitish, darkening as they develop.

3. Main hosts

• Vegetable crops: tomato, cucumber, courgette, pepper, bean, aubergine.
• Ornamentals: poinsettia, gerbera, chrysanthemum, fuchsia.
• Other crops: strawberry, tobacco.
• Highly polyphagous species, with dozens of relevant hosts in the greenhouse.

4. Symptoms and damage

• Yellowing and weakening of the leaves due to sap sucking.
• Abundant production of honeydew, favouring the development of sooty mould.
• Reduction of photosynthesis and plant vigour.
• Indirect damage: virus transmission, although less efficient than Bemisia tabaci.
• In greenhouses, it can cause significant yield losses.

5. Biological cycle

• Rapid cycle in a protected environment: 20–30 days, depending on temperature.
• Eggs laid on the underside of the leaves.
• Nymphal development with 4 fixed instars.
• Adults live 2–4 weeks, with high reproductive capacity.
• Multiple generations per year; in the greenhouse, a continuous cycle throughout the year.

6. Monitoring

• Direct observation of the underside of the leaves for nymphs and pupae.
• Blue and yellow sticky traps for detection and counting of adults.
• Frequent monitoring in greenhouses, especially during warm periods.
• Assessment of the presence of honeydew and sooty mould.
• Visual control of stress symptoms and plant decline.

7. Management measures

• Cultural: elimination of crop residues; use of insect-proof nets; adequate ventilation; avoiding excess nitrogen fertilisation; removal of heavily infested leaves.
• Biological: release of beneficials such as Encarsia formosa, Eretmocerus eremicus, Amblyseius swirskii, A. montdorensis; conservation of natural predators.
• Integrated protection: intensive monitoring; use of sticky traps; rotation of modes of action to prevent resistance; judicious application of authorised insecticides, targeted at the underside of the leaves.

Bibliographic references

• EPPO Global Database – Trialeurodes vaporariorum.
• CABI Invasive Species Compendium – Trialeurodes vaporariorum.
• Byrne, D. N. et al. (1990). Biology and ecology of whiteflies.
• Stansly, P. A. et al. (2005). Biological control of whiteflies in greenhouse crops.
• van Lenteren, J. C. et al. (2018). Integrated pest management in protected crops.