Whiteflies and tomato viruses in greenhouses: protect clean transplants and contain spread
Reviewed: · SeedMatchGroup
Some whitefly species can transmit specific tomato viruses: for example, the silverleaf/sweetpotato whitefly (Bemisia tabaci) transmits tomato yellow leaf curl virus (TYLCV), and the greenhouse whitefly (Trialeurodes vaporariorum) transmits tomato infectious chlorosis virus (TICV). Not every whitefly carries every virus. The most practical defence is to start with clean transplants, inspect incoming plants, keep tools and areas clean, use suitable screens where practical, monitor whiteflies and symptoms weekly, handle suspect plants according to local guidance and involve your extension service early.
Identification aid, not a diagnosis. Virus symptoms can resemble nutrient, chemical or environmental problems; only laboratory testing can confirm a virus. Contact your local extension or plant-health service.
Which whiteflies transmit which tomato viruses?
Whiteflies feed on plant sap, and some species can carry plant viruses from infected to healthy plants. The relationship is specific: a given virus is transmitted by particular whitefly species.
Examples documented by UC IPM include tomato yellow leaf curl virus (TYLCV), transmitted by Bemisia tabaci, and tomato infectious chlorosis virus (TICV), transmitted by the greenhouse whitefly. A related virus, tomato chlorosis virus (ToCV), is transmitted by several whitefly species. Which species and viruses matter depends on your region.
Why are clean transplants so important?
Infected or infested transplants can bring both the vector and the virus into a new crop. Plants infected early usually suffer most. Buying from reliable propagators, inspecting each delivery and keeping young plants protected reduce the chance of introducing problems at the start of the crop.
What does a greenhouse IPM checklist include?
- Inspect incoming plants, including leaf undersides, before they enter production; hold suspect batches separately.
- Clean tools, benches, trolleys and propagation areas, and control weeds and volunteer plants in and around the greenhouse that can host whiteflies or viruses.
- Use suitable insect screens on vents and doors where practical, and check that screening does not reduce ventilation below what the crop needs.
- Monitor whiteflies with yellow sticky cards and leaf checks, and record counts weekly by zone.
- Watch for virus-like symptoms and handle suspect plants according to local guidance, which may include removal in closed bags.
- Consider break periods between crops and clean-up of crop residues where your local advice recommends it.
- Ask your extension service about locally relevant whitefly species, viruses, resistant varieties and biological control options.
What about insecticides and biological control?
Use only products registered for tomatoes in your country and growing system, and follow the exact label; whiteflies can develop resistance, so local advice matters. Biological control is used in many greenhouses. Ask your extension service or a licensed professional which options apply. This guide does not recommend products or rates, and no programme guarantees eradication.
Weekly scouting sheet: whiteflies and virus-like symptoms
Use the same sticky-card positions each week and record counts per card and per zone.
| What to check | Where | Notes / count |
|---|---|---|
| ☐ Adult whiteflies on yellow sticky cards | ||
| ☐ Adults, eggs or nymphs on leaf undersides | ||
| ☐ Incoming transplant batch inspected (supplier, date) | ||
| ☐ Yellowing, curling or stunting on young growth | ||
| ☐ Interveinal yellowing or chlorosis on older leaves | ||
| ☐ Weeds or volunteer plants near doors and vents |
Greenhouse environment observation checklist
- Record temperature and relative humidity at canopy height, morning and evening.
- Note condensation on roof, walls or leaves, and how long leaves stay wet.
- Check that fans and vents run as set and air moves through dense canopy areas.
- Record irrigation start/end times and whether foliage or floors stay wet into the evening.
- Note cold spots, drips from structures and areas with poor drainage.
- Write down any change in heating, screens or ventilation settings this week.
Frequently asked questions
Do all whiteflies transmit tomato viruses?
No. Transmission is specific: particular whitefly species transmit particular viruses. For example, Bemisia tabaci transmits TYLCV and the greenhouse whitefly transmits TICV.
Can I tell a virus from symptoms alone?
Not reliably. Virus symptoms can look like nutrient, chemical or environmental problems. Laboratory testing through a local plant-health service is needed to confirm a virus.
Can whiteflies and viruses be eradicated from a greenhouse?
Eradication cannot be promised. Clean transplants, screening, sanitation, monitoring and local expert advice help reduce introduction and contain spread.
Should screens be installed on every greenhouse?
Screens can help keep whiteflies out where practical, but they also reduce airflow. Ventilation and climate needs should be checked before choosing a screen.
Related SeedMatch planning tools
- Greenhouse climate control systems
- Greenhouse sensors and automation
- Greenhouse climate calculator
- Drip irrigation planning
Optional: if you are scoping climate, screening or irrigation upgrades for a commercial project, our team reviews requests before approaching independent suppliers.
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