In South Florida, whiteflies are found year-round in outdoor gardens. Citrus, squash, poinsettia, potato, cucumber, grape, tomato and hibiscus are commonly infested. The whitefly (Trialeurodes vaporariorum) is a sap-sucking insect that is often found in thick crowds on the undersides of leaves. When infested plants are disturbed, great clouds of the winged adults fly into the air. Both nymphs and adults damage plants by sucking the juices from new growth causing stunted growth, leaf yellowing and reduced yields. Plants become weak and susceptible to disease. Like aphids, whiteflies secrete honeydew, so leaves maybe sticky or covered with a black sooty mold. They are also responsible for transmitting several plant viruses.
Adults (1/16 inch long) are moth-like insects with powdery white wings and short antenna. They are easily recognized and often found near the tops of plants or on stem ends. Wingless nymphs are flattened, oval and almost scale-like in appearance. After the first crawler stage, they settle down and attach themselves to the underside of leaves and begin feeding.
Young nymphs overwinter on the leaves of host plants. In late spring adult females deposit 200-400 eggs in circular clusters on the undersides of upper leaves. The eggs hatch in 5-10 days and become nymphs, which resemble small mealybugs, move a short distance from the egg before flattening themselves against the leaf to feed. The remaining nymphal stages (2nd, 3rd and 4th) do not move. A non-feeding pupal stage follows and within a week, young adults emerge to repeat the cycle. There are many generations per year. Whiteflies develop from egg to adult in approximately 25 days at room temperature. Adults may live for one to two months.
All of the immature stages are easily overlooked. They are usually pale, almost translucent, and blend with the color of the leaf to which they are attached. Superficially they are similar to several scale insects.
Whitefly Natural Solutions
These small sucking insects have developed resistance to many synthetic pesticides making chemical control difficult. Here’s how to get rid of whitefly using natural methods and predators. These methods work best when populations are just getting started and still low.
Yellow sticky traps are helpful for monitoring and suppressing adult populations.
If found, use a hose on plants with a strong stream of water and reduce pest numbers.
Natural predators of this pest include ladybugs and lacewing larvae, which feed on their eggs and the whitefly parasite which destroys nymphs and pupae. For best results, make releases when pest levels are low to medium.
Insecticidal soap, neem oil and botanical insecticides can be used to “knock down” heavily infested areas.
When natural methods don’t work, pesticides sprays can be used. The key to using these product is to directly spray the target pest. This would be the under and upper surfaces of the leaves where they congregate. Two applications 3 to 5 days apart should give control the situation. Hugh Turner Pest Control technicians will evaluate the environment and provide a specified treatment for you precise situation.
The pesticide application will also help get rid of ants. Ants feed on the honeydew that whitefly produce and will protect these pests from their natural enemies.
Whitefly Identification and Treatment