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How to Identify and Get Rid of Whiteflies on Plants

whiteflies and whitefly eggs on a green leaf
Image Credit:
D. Kucharski, K. Kucharska/Shutterstock
Written By: Christopher Burnett Garden Writer

What are those tiny white bugs on your plants? Noticing little white fly-like insects? You may be dealing with a whitefly infestation. Here are some tips on how to identify, control, and get rid of whiteflies!

What Are Whiteflies?

Whiteflies are soft-bodied, winged insects closely related to aphids and mealybugs. Despite their name, whiteflies are not a type of fly, though they have wings and can fly.

Whiteflies can be as small as 1/12 inch, are somewhat triangular in shape, and are often found in clusters on the undersides of leaves. They are active during the day and scatter when disturbed, making them easier to spot than some nocturnal insect pests.

There are hundreds of species of whiteflies, but most affect only a small number of host plants. However, a few whitefly species affect a more comprehensive range of plants, making them the most problematic in horticulture. These whitefly species include the greenhouse whitefly, banded winged whitefly, giant whitefly, and silverleaf whitefly, among others. Silverleaf whiteflies, which are slightly smaller and more yellow than other whiteflies, are especially common in the southern United States. 

Where Are Whiteflies Found?

In USDA Zone 7 and colder, whiteflies cannot survive winter outdoors, so their presence tends to be limited to indoor plants or greenhouse environments. However, if outdoor plants are bought from an infested greenhouse, whiteflies may become a seasonal outdoor garden pest. (Always inspect plants before bringing them home!) 

In warmer regions, whiteflies can overwinter and reproduce outdoors throughout the year, so that they can be a problem for both indoor and outdoor plants.

You’ll often start to see whiteflies in mid- to late-summer when it gets warm and humid.

Which Plants Are Susceptible to Whiteflies?

Whiteflies can be found on various plants, from ornamental flowers to warm-weather vegetables, including tomatoes, eggplants, peppers, and okra. Some species may attack sweet potatoes, plants from the cabbage family, and citrus trees. Indoors, they will feed on most common houseplants, especially those with soft, smooth leaves.

Identification

How to Identify Whiteflies

Like aphids, whiteflies use their piercing mouthparts to suck up plant juices and, in turn, produce a sticky substance known as honeydew, which, left on its own, can cause fungal diseases—such as sooty mold—to form on leaves.

With heavy whitefly feeding, plants quickly become extremely weak and may be unable to carry out photosynthesis. Leaves wilt and turn pale or yellow, growth is stunted, and eventually, leaves may shrivel and drop off the plant. 

Honeydew is a sign that the whiteflies have been feeding for several days. You might also see ants, which are attracted to the sweet honeydew. 

Where to Find Whiteflies on Plants

Whiteflies tend to prefer to feed on new growth, so check around any newly unfurled leaves first.

Check the undersides of leaves—especially around the veins—for white insects, even if they aren’t immediately visible, and feel leaf surfaces for sticky honeydew. If the whiteflies are feeding, they’ll suddenly all fly off the leaves in a swarm, so it’s very obvious.

You may also find eggs laid on the undersides of leaves. This is the beginning of a new generation! When the eggs hatch, the larvae look like teeny white ovals without legs; they don’t move but immediately start sucking the plant juice. This is why gardeners often miss whiteflies until it’s too late. Adult females can produce up to 400 eggs, which hatch about 1 week to 1 month after laying. They are usually laid in a circular pattern. Eggs are pale yellow when newly laid and brown when about to hatch.

whiteflies laying eggs on the underside of a green leaf
Whiteflies congregate on the undersides of leaves and lay their tiny white eggs in this secure spot. Photo Credit: University of Florida.

Control and Prevention

How to Get Rid of Whiteflies

There are various solutions and traps that you can use to control whiteflies. The biggest tip is to start early! In the mornings and evenings, as you wander the garden or tend to your houseplants, check the back of the leaves for eggs or notice when little bugs fly away as you approach your plants.

  • Always start with blasting whiteflies (as with aphids and many other insect pests) with your watering hose or a spray bottle. This will cause them to scatter, which will dislodge nymphs and eggs to some extent.
  • Consider spraying your plants’ leaves with insecticidal soap, following the directions on the packaging. Be sure to spray the undersides of the leaves too. Follow up two or three times, as necessary. According to M. L. Flint, extension entomologist emeritus at the UC Davis Department of Entomology, “Most less-toxic products such as insecticidal soaps, neem oil, or petroleum-based oils control only those whiteflies that are directly sprayed. Therefore, plants must be thoroughly covered with the spray solution, and repeat applications may be necessary.”
    • Tip: Spray plants in the evening when temperatures are cooler, as midday heat may cause an adverse reaction in your plant. Plus, spraying in the evening allows you to avoid accidentally spraying any pollinators or beneficial insects.
  • According to the National Gardening Association, the following simple homemade mixture should be helpful to control and deter whiteflies: Use a mix of dish soap and water. A good squirt of soap to a gallon of water should work. As mentioned above, only spray in cooler temperatures; late in the day is best. The NGA mixture is a pretty benign combination, and whiteflies are nearly impossible to get rid of, so it’s best to try more preventative tactics first, as mentioned below.
  • If all else fails and your whitefly population is persistent, you can (carefully) use a handheld vacuum every few days to remove them from your plants. This gets rid of both nymphs and adults. Just be sure to avoid emptying your vacuum into a trash can inside your home afterward!

How to Prevent Whiteflies

  • Your first line of defense should be inspecting all plants for pests before you bring them home and keeping any new additions away from the rest of your plants for a period of time. This will allow you to identify and curtail any existing pest or disease issues.
  • Keeping natural predators around will prevent whiteflies from ever exploding in population. For this reason, avoid using insecticides. Ladybugs, spiders, green lacewing larvae, and dragonflies are a few of the many beneficial insects that can control a whitefly population. Hummingbirds are another natural predator. Try creating a habitat that will attract dragonflies and damselflies (which also helpfully eat mosquitoes) or beautiful hummingbirds.
  • When it comes to whiteflies, avoid chemical insecticides; they’re usually resistant, and all you’ll do is kill the beneficial insects—whiteflies’ natural predators—and the insects that pollinate the garden for a better harvest.
  • Mulch early in the season with aluminum reflective mulch, especially around tomatoes and peppers. The reflective mulch makes it challenging for whiteflies to find their preferred host plants.
  • Set out yellow index cards coated with petroleum jelly to monitor whiteflies, especially for tomatoes, peppers, sweet potatoes, or cabbage crops. A half-and-half mixture of petroleum jelly and dish soap, spread over small boards painted bright yellow, is sticky enough to catch little whiteflies too. To whiteflies, the yellow color looks like a mass of new foliage. The bugs are attracted to the cards, get stuck in the jelly, and die.

Garden Pests

About The Author

Christopher Burnett

Christopher Burnett

Garden Writer

Having grown up in rural New Hampshire, Chris has a great appreciation for all things outdoors, especially when it comes to native flora and fauna.Chris is an avid gardener, maintaining a small vegeta...

Read more from Christopher Burnett

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Comments

<a title="View user profile." href="/author/editors">The Editors</a> Sat, 09/07/2013 - 14:33

Yellowing leaves is often an indicator of early blight on your tomatoes. Avoiding getting leaves wet when watering.  Make sure the tomatoes have plenty of air circulation. For the most effective control, especially during rainy periods, apply a fungicide, taking care to get good coverage on the upper and lower leaf surfaces, especially on older leaves.

 <span>Cheryl Haselwood</span> Mon, 08/26/2013 - 21:45
Will the spray work on the lawn too?
<a title="View user profile." href="/author/editors">The Editors</a> Tue, 08/27/2013 - 15:52

Yes, insecticidal soaps can be used on lawns. Natural predators such as lady beetles are also a good idea.

 <span>Becky Dressing</span> Tue, 08/20/2013 - 18:29
I have whiteflies on my hostas. I also have quite a few praying mantis in my garden. Can I get rid of the flies safely and not hurt the praying mantis?
<a title="View user profile." href="/author/editors">The Editors</a> Wed, 08/21/2013 - 15:34

The solutions proposed above are pretty consistently recommended:

Spray with insecticidal soap. Follow up twice or three times.

Introduce ladybugs and spiders to help control whitefly population.

Set whitefly traps.

Or try this: 2 parts rubbing alcohol, 5 parts water, and 1 tablespoon liquid soap. Spray the mixture on the foliage of garden plants that are susceptible to these pests.

The mantis will probably be fine. Do not apply these treatments directly on it.

 <span>Cici</span> Mon, 07/22/2013 - 22:49
My condo parking lot is infested with whiteflies. They leave nasty black residue all over my car. This needs to be scrubbed off by hand, does not come off in the carwash that I go to. What can I use on my car to keep them off?
<span>Sofia Frank</span> Sun, 10/27/2013 - 22:42
I have the same problem as CiCi , my assigned parking at condominimum is under atree infewsted with whitefly,when my car stands there overnight its full of sticky residue and brown spots,i complained several times to the board, to no avail, they said they treated the tree. i am afraid the paint will evenually be ruined, they dont care its been 2 years. anybody knowws where do I complaine ? I am very frastrated , my car has to be detailed every time. Should I complain to the board of condominimums ? Will that help ?
<a title="View user profile." href="/author/editors">The Editors</a> Thu, 07/25/2013 - 14:13
It sounds like a case of the rugose spiraling whitefly. While we have no recommendations for how to keep droppings from sticking to your car, we can offer a solution to make clean-up a little easier. Try scrubbing the spots with a cotton rag dipped in either baby oil or vegetable oil. Rinse your car after.
<span>William Caldwell</span> Wed, 06/12/2013 - 13:31
Will the whitefly population eventually dissipate later in the spring or early summer season?
<a title="View user profile." href="/author/editors">The Editors</a> Mon, 06/17/2013 - 14:55
With whiteflies, it all depends on where you live. They love warm weather and will breed more rapidly at the peak of summer. In parts of California and the South, they breed all year, moving from one host to another as plants are harvested or dry up. Only cold weather kills them off. Therefore, it's often best to plant early in the spring to get the plants to full maturity before white fly populations grow. They are sluggish in cold temperatures.