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Whiteflies on Trees: Signs, Damage, and How to Protect Your Property

Submitted by Elisa Edelstein

If you have ever walked under a tree and felt a sticky mist on your skin, or found your patio furniture, car, or deck is coated in a shiny film that turns black over time, whiteflies may be the cause. These tiny insects are easy to overlook until the mess they leave behind becomes impossible to ignore. They can weaken your trees and turn the space beneath them into a sticky, grimy annoyance if they go unchecked. With the help of an arborist, whiteflies can be managed. 

What are whiteflies?

Despite the name, whiteflies are not a part of the fly family. They are little, sap-sucking insects that are more closely related to aphids, scales, and mealybugs. Adults are around 1/16 of an inch long and are known for their powdery, white wings. They gather in bunches on the undersides of leaves, and if you brush against an infested branch, you will frequently see a small cloud of whiteflies scatter.

Whiteflies reproduce quite quickly, and a single female can lay dozens of eggs. In warm climates or weather, several generations can overlap in a single season. The quick turnover can create a more serious condition in a matter of weeks.

Signs of a whitefly infestation

Whiteflies are small, but the evidence they leave is not. 

Watch for these warning signs:

  • Small clusters of tiny white insects on the undersides of leaves
  • A cloud of small white insects when foliage is disturbed
  • Leaves turning yellow, wilting, or premature leaf drop
  • A sticky and shiny coating on leaves, branches, or below the tree
  • Sooty, black patches on leaves and nearby surfaces like chairs or a deck
  • A large number of ants going up and down the trunk

When many of these signs show up at once, they generally indicate a whitefly infestation and warrant a call to your arborist for a professional opinion. 

How whiteflies damage your trees

Whiteflies feed by drawing out sap from leaves. They puncture the leaf and use their needle-like mouths to suck the sap. While a few whiteflies may not be detrimental, many can cause nutrient and moisture deficiencies, visibly stressing a tree and causing leaves to turn yellow, curl, and drop early. They may also slow growth and lead to overall decline.

A weak tree becomes vulnerable to other conditions. Chronic feeding leaves it more susceptible to drought stress, various insects, and diseases. Established shade trees rarely die from whiteflies alone, but dense hedges and ornamentals can decline rapidly under heavy, continuous pressure.

How whiteflies affect your property

The most frustrating part of a whitefly problem often has nothing to do with the tree itself. As whiteflies feed, they excrete a sugary waste called honeydew. It rains down onto whatever is below, and leaves a sticky residue on outdoor furniture, cars, patios, walkways, and pool decks.

That honeydew then becomes a breeding ground for black sooty mold, a fungus that grows on the sugary film. Sooty mold coats leaves and surfaces in a dark, grimy layer that is rather difficult to clean and obstructs the sunlight your tree's leaves need to stay healthy. The sweet honeydew also attracts other insects such as ants and wasps. 

Common whitefly types and vulnerable trees

Several whitefly species affect landscape trees and shrubs, including:

  • The ficus whitefly (Singhiella simplex)

  • Giant whitefly (Aleurodicus dugesii)

  • Citrus whitefly (Dialeurodes citri)

  • Rugose spiraling whitefly (Aleurodicus rugioperculatus)

Commonly affected plants include ficus, citrus, gumbo limbo, black olive, palms, and a wide range of broadleaf ornamentals and shrubs.

Whiteflies thrive in warm, mild conditions, so infestations tend to be most severe across the South, the Gulf Coast, and California. Warm spells can extend their activity in other regions as well, which makes seasonal monitoring worthwhile no matter where you live.

How to control and prevent whiteflies

For heavy or recurring infestations, targeted treatments applied at the right stage of the whitefly life cycle make the biggest difference. Keep trees pruned and well cared for. ISA Certified Arborists can identify the species, gauge the severity, and recommend a tree-safe plan that protects your trees, your property, and the beneficial insects you want to keep around.

Contact us today to schedule a consultation with an expert arborist.

FAQs

  • Whiteflies are tiny, sap-sucking insects that gather on the undersides of leaves, where they feed on trees and shrubs. Though named for their powdery white wings, they are more closely related to aphids and scale than to true flies. They reproduce quickly, produce sticky honeydew, and can weaken a tree over time if left untreated.

     

  • Whiteflies damage trees by piercing leaves and drawing out sap, which robs the tree of nutrients and moisture. Signs include yellowing leaves, premature leaf drop, and stunted growth. The insects also excrete honeydew that fuels black sooty mold, blocking the sunlight the leaves need. Over time, a heavy infestation weakens the tree and leaves it vulnerable to other pests and disease.

     

  • The sticky substance whiteflies leave behind is honeydew, a sugary waste product they excrete as they feed. Honeydew coats leaves, branches, and anything beneath the tree, including cars, patios, and furniture. It also encourages black sooty mold and draws ants and wasps. Rinsing surfaces helps, but treating the whitefly infestation is the only lasting fix.

     

  • Getting rid of whiteflies on your trees usually takes a combination of methods. Spraying leaves with water dislodges adults, while horticultural oils and insecticidal soaps target eggs and nymphs on leaf undersides. Encouraging natural predators such as lady beetles and lacewings also helps. For heavy or recurring infestations, ISA Certified Arborists can recommend a targeted, tree-safe treatment plan.

     

  • Whiteflies are not harmful to people or pets, since they do not bite, sting, or spread disease to humans. Their real impact is on trees and property. Large swarms can be a nuisance, and the honeydew and sooty mold they create leave sticky, black residue on outdoor surfaces. The main concern is your trees' health.

     

  • Trees most vulnerable to whiteflies include ficus, citrus, gumbo limbo, black olive, and many broadleaf ornamentals, along with palms and various shrubs. Whiteflies thrive in warm, mild climates, so infestations are most common across the South, Gulf Coast, and California. Stressed or over-fertilized trees attract them more readily, so consistent, professional tree care is an effective defense.