Whiteflies are tenacious, destructive pests that cause extensive damage to many types of plants, from tomatoes and sweet potatoes to roses and houseplants. Closely related to aphids and mealybugs, they get their name from the waxy, white powder that covers them. Whiteflies reproduce rapidly, especially during warm weather, and become extremely difficult to control once populations build. With warm conditions — outdoors or indoors — whiteflies reproduce year-round. Both adult whiteflies and immature nymphs damage plants.
Adult whiteflies have yellow-white, wedge-shaped bodies and white wings. About 1/10 inch long, they resemble small, white moths. The waxy powder on their wings and bodies is very similar to that of mealybugs. Depending on the species, wingless whitefly nymphs vary in color from translucent yellow-white to black.
Signs or Damage of Whiteflies
Whiteflies congregate in large numbers on the undersides of leaves. They damage plants by piercing the tissue and sucking out vital plant sap. Like aphids and mealybugs, whiteflies excrete a sticky, sweet substance known as "honeydew," which often attracts nuisance ants and develops black sooty mold. Damaged leaves turn yellow or silvery and become dry or drop from plants. Vegetables and fruits become deformed or fail to develop. Heavily infested plants eventually die.
How to Control Whiteflies
Effective whitefly control starts at the earliest possible sign of the pest. If you've had whitefly problems in the past, don't wait. Be proactive to prevent repeats. GardenTech brand offers highly effective options to kill whiteflies and protect plants:
- Sevin Insect Killer Ready to Use2 simplifies targeted spot treatments of individual plants or small garden areas. Adjust the sprayer nozzle to get your desired spray width and kill whiteflies on contact. Spray to cover all plant surfaces thoroughly. Give special attention to the undersides of leaves.
- Sevin Insect Killer Concentrate provides an economical alternative for large-scale preventive and active whitefly treatment. Use with a pump-style sprayer that allows you to adjust your spray and easily reach the undersides of plant leaves. Treat to cover all plant surfaces thoroughly, including leaves close to the ground. This product kills by contact and protects against whiteflies for up to three months.
Whitefly Control Tip: Whitefly infestations take over houseplants and spread quickly. Remove and destroy heavily infested leaves. To treat houseplants, take them outside and spray all plant parts thoroughly, especially the undersides of leaves. Allow the spray to dry completely before bringing houseplants back inside.
Always read product labels thoroughly and follow instructions, including guidelines for listed plants and pests, application frequency and pre-harvest intervals (PHI) for edible crops.
GardenTech is a registered trademark of Gulfstream Home and Garden, Inc.
Sevin is a registered trademark of Tessenderlo Kerley, Inc.
"Trialeurodes vaporariorum" by Erin Finkle is licensed under CC BY 2.0 "Whiteflies and their pupae on a leaf" by Scot Nelson licensed under CC BY 2.0 (public domain)