The Hidden Dangers of Whiteflies in and Around Your Home

Whiteflies are not dangerous to people: they do not bite, sting or carry human diseases. Their hidden dangers are to everything else around your home, from the houseplants on your windowsill and the tomatoes in your garden to your car, patio and pool, and to your family when people reach for the wrong product to get rid of them.

Because whiteflies hide on the undersides of leaves, these problems often build for weeks before anyone notices. Here is what whiteflies can really do in and around a South Florida home, and how to keep each risk small.

Are Whiteflies Harmful to Humans?

No. Whiteflies are small sap-feeding insects, related to aphids and scales rather than true flies, and they feed only on plants. University of Minnesota Extension describes the whiteflies that infest houseplants as harmless to people and other property, and the University of Florida’s whitefly FAQ notes that the white waxy material some species produce is not harmful to plants or animals.

That does not mean they are harmless to a household. The dangers are indirect:

Danger 1: Viruses in Your Vegetable Garden

This is the most serious and least known risk. The silverleaf whitefly, also called the sweetpotato whitefly, spreads tomato yellow leaf curl virus (TYLCV), a very common disease of tomato plants, and the virus is spread only by infected whiteflies, according to UF/IFAS Extension. Extension agents call it “the mosquito of the plant world.”

How it spreads:

• An adult whitefly picks up the virus after feeding on an infected plant for at least 5 to 10 minutes.
• About 10 hours later, it can pass the virus to healthy plants, and it can carry it for 10 to 12 days.
• The virus does not spread through seed, touch, soil or tomato stakes, but infected transplants and wind-blown whiteflies can move it between gardens.

Infected plants have small, crumpled leaves that curl upward and turn yellow at the edges. Plants infected young may stop growing and never set fruit.

Protecting a Home Vegetable Garden

• Choose tomato varieties tolerant of TYLCV.
• Inspect transplants for whiteflies under the leaves before you buy or plant them.
• Use silver reflective mulch to deter whiteflies, and keep weeds down.
• Check plants at least twice a week for adults and nymphs.
• Bag infected plants before cutting them out, seal the bag and put it in the trash, not the compost.

Not every whitefly carries viruses. The University of Florida notes that the ficus, rugose spiraling and Bondar’s nesting whiteflies, the main landscape pests, have not been linked to any known plant viruses.

Danger 2: Whiteflies Indoors on Houseplants

Indoor whitefly problems almost always start with a plant. The greenhouse whitefly has more than 250 host plants, including poinsettia, begonia, hibiscus, lantana and tomato, according to Colorado State University Extension. Indoors there is no cold season, so infestations can continue all year.

They multiply quickly. A female greenhouse whitefly can lay 400 eggs over up to two months, eggs hatch in five to seven days, and a generation takes three to four weeks in good conditions. University of Minnesota Extension notes that infested houseplants yellow and drop leaves and lose vigor, though they are usually not killed.

Keeping Whiteflies Off Your Houseplants

• Quarantine new plants. Inspect them, brush the leaves to flush out adults and keep them apart for 1 to 2 weeks.
• Use yellow sticky cards. Adults are strongly drawn to yellow, so cards near plants help you spot them early.
• Check leaf undersides with a hand lens for eggs and flat nymphs.
• Use insecticidal soap carefully. It must contact the insects, so coat leaf undersides and repeat every 7 to 10 days, early or late in the day to avoid leaf scorch. Follow the label.
• Discard badly infested plants rather than letting them seed the rest of your collection.

Danger 3: Honeydew on Cars, Patios and Pools

Every whitefly feeding on a tree above your driveway is dripping honeydew, a sticky, sugary waste. The University of Florida’s whitefly FAQ warns that honeydew can damage the finish on cars and other painted objects if it is not washed off, and black sooty mold grows wherever it collects.

The rugose spiraling whitefly is especially messy. The Florida Department of Agriculture and Consumer Services reports that its honeydew, wax and dead adults fall on cars, patios and furniture and can clog pool filters. For the black coating on plants, see why your hedge is turning black.

Limiting the Mess Around Your Home

• Park away from infested trees during an outbreak, especially black olive and gumbo limbo over driveways.
• Rinse cars and outdoor furniture with water and a mild car-wash soap as soon as you notice sticky spots, before sooty mold sets in.
• Clean pool skimmers and filters more often while trees overhead are infested.
• Cover patio cushions or store them when not in use.

These steps only manage the symptoms. The honeydew keeps falling until the whiteflies in the canopy are under control, so cleanup works best alongside treatment of the infested plants.

Danger 4: Stinging Ants and Wasps Drawn to Honeydew

Honeydew is food for other insects. FDACS notes that rugose spiraling whitefly honeydew attracts stinging ants and honeydew wasps. That turns a hedge you trim or a tree you prune into a place where you can get stung. If you see ants trailing up a trunk, check the leaves above for sucking insects. Our ant pest library helps you identify which ants you are dealing with.

Danger 5: The Wrong Treatment Around Your Family

The most real danger to people comes from well-meant DIY treatment: spraying a garden insecticide in a kitchen full of herbs, using a product not labeled for vegetables, or drenching a hedge where children and pets play. Repeated broad sprays also kill the beneficial insects that hold whiteflies in check, so the problem returns. Our article on common mistakes in whitefly treatments explains what goes wrong.

Danger 6: The Slow Loss of Your Landscape

Outside, whiteflies drain ficus hedges, palms and shade trees. The University of Florida notes they do not typically kill large, healthy trees, shrubs and palms, but young, newly planted or stressed plants are more at risk, and leaf loss in a privacy hedge happens only after several months of infestation. By the time you notice, the problem is well established.

How to Protect Your Home From Whiteflies

1. Inspect new plants, indoors and out, before bringing them home.
2. Check the undersides of hedge, palm and garden leaves every couple of weeks.
3. Wash honeydew off cars and outdoor furniture promptly.
4. Keep plants watered and fertilized so they tolerate feeding better.
5. Treat only when whiteflies are confirmed, and only with products labeled for that use.

For hedges, palms and trees around your home, Toro’s whitefly control service starts with a free inspection, including the undersides of the leaves, to identify the species and how heavy the infestation is, followed by a clear plan and quote before any work begins. If you also want indoor pests covered year-round, see our residential pest control services. You can learn more about the insects themselves in our whitefly pest library.

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Frequently Asked Questions

Educational content. This article is for general information about pests in South Florida and is not medical, legal or professional advice. If you have a bite, sting or allergic reaction, contact your doctor; in an emergency, call 911. Pest problems vary from home to home, so a licensed professional should inspect before treatment. When using any pesticide, always read and follow the product label.

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