Age-Old Wisdom meets Modern Tools
How to Identify and Get Rid of Whiteflies
Whiteflies and their small, oval nymphs reside on the undersides of leaves and cause the leaves to become sticky with honeydew.The Ohio State University
Here are tips on how to identify, control, and get rid of whiteflies.
What are Whiteflies?
What are those little white flying bugs on your plants?
Whiteflies, also known as aleyrodidae, are soft-bodied, winged insects closely related to aphids and mealybugs. They can be found in most any region, but they are so tiny that they are usually camouflaged.
They can be as small as 1/12 of an inch, somewhat triangular in shape, and are often found in clusters on the undersides of leaves. They are active during the daytime, so they are easier to spot than some other nocturnal pests. Whiteflies are capable of overwintering and reproducing throughout the year in warmer climates.
One common species of whitefly is the silverleaf whitefly, which is slightly smaller and more yellow than other whiteflies. Silverleaf whiteflies are especially common in southeastern states. All species of whiteflies affect a wide variety of plants.
You’ll often see whiteflies in mid- to late-summer when it gets warm; they are also a common pest in greenhouses.
How to Identify Whiteflies on Plants
Whiteflies suck plant juices and, in turn, produce a sticky substance known as honeydew. Honeydew left on its own can cause fungal diseases to form on leaves.
Due to whitefly feeding, plants will quickly become extremely weak and may be unable to carry out photosynthesis. Leaves will wilt, turn pale or yellow, and growth will be stunted.
Honeydew is a sign that the whiteflies have been feeding for several days. You might also see ants, which are attracted to the honeydew.
Check undersides of leaves around the veins for white insects, even if they aren’t visible, and feel leaf surfaces for 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 will look like teeny white ovals without legs; they don’t move but they immediately start sucking the plant juice. This is why gardeners miss the whiteflies until it’s too late. Adult females can produce up to 400 eggs, which can hatch in between one week and a month. They are usually laid in a circular pattern. Eggs are pale yellow when newly laid and brown when about to hatch.
Photo Credit: University of Florida. Whiteflies congregate on the undersides of leaves and lay their tiny white eggs in this secure spot.
Control and Prevention
How to Get Rid of Whiteflies
To control whiteflies, there are various solutions and traps that you can use. The biggest tip is: start early! In the mornings and evenings, as you wander the garden, 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 (and aphids and many insects) with your watering hose. This will cause them to scatter. Then, spray your leaves with insecticidal soap. Coat them; be sure to spray the undersides of leaves.Only spray plants when temperatures are cooler—such as late in the day, as heat may cause an adverse reaction in your plant. Follow up 2 or 3 times.
- According to the National Gardening Association, this homemade mixture should be helpful to control and deter whiteflies: Use a mixture of dishwashing liquid, such as Palmolive with lemon, and water. A good squirt of soap to a gallon of water should work. As mentioned above, only spray in cooler temperatures; early in the morning or 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, as mentioned below.
- If all else fails and your whitefly population is persistent, you can use a handheld vacuum every few days to remove them from your plants. This gets rid of both nymphs and larvae.
How to Prevent Whiteflies
- Keeping natural predators around will prevent whiteflies from ever exploding in population. Ladybugs, spiders, lacewing larvae, and dragonflies are a few of 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 end up doing is killing the beneficial insects—their natural predators—and the insects which pollinate the garden for a better harvest!
- Mulch early in the season with aluminum reflective mulch, especially when it comes to tomatoes and peppers. The reflective mulch makes it challenging for whiteflies to find their host plants.
- Set out yellow index cards coated with petroleum jelly to monitor whiteflies, especially when it comes to tomatoes, peppers, sweet potatoes, or cabbage crops. A half-and-half mixture of petroleum jelly and dishwashing detergent, spread over small boards painted bright yellow, is sticky enough to catch little whiteflies, too. To whiteflies, the color yellow looks like a mass of new foliage. The bugs are attracted to the cards, get stuck in the jelly, and die.