Silverleaf Whitefly

Several species of whiteflies may infest eggplants, but silverleaf whitefly is the primary one. Whiteflies are found mostly on the undersides of leaves. They fly readily when plants are disturbed.

The tiny, elongated eggs hatch into a first larval stage that has legs and antennae and is mobile. Both legs and antennae are lost after the first molt and subsequent stages remain fixed to the leaf surface. Adults are tiny (0.06 inch, 1.5 mm long), yellowish insects with white wings. Silverleaf whiteflies hold their wings somewhat vertically tilted, or rooflike, over the body; the wings do not meet over the back but have a small space separating them.

Whiteflies damage eggplants by sucking enormous quantities of sap and covering plants with sticky honeydew. Black sooty mold grows over the honeydew, lowering the photosynthetic capacity of the plant and making the fruit unattractive. Currently, no virus problems associated with whiteflies have been reported on eggplant.

Whitefly populations are not consistent from year to year, so monitoring is important in detecting and preventing the development of populations in any given year. In addition, an integrated pest management program for whiteflies includes following good cultural practices, such as host-free periods, and using pesticides only when necessary.

Silverleaf whitefly is an introduced pest that has escaped its natural enemies. Some indigenous native parasites and predators do attack it, but do not keep it below damaging numbers.

Adult silverleaf whiteflies are repelled by silver- or aluminum-colored mulches. Place reflective polyethylene mulches on planting beds before transplanting to significantly reduce rate of colonization by whiteflies and delay the buildup of damaging numbers of early season whiteflies by 4 to 6 weeks. The mulches lose their effectiveness when more than 60% of the surface is covered by foliage, or if dust or soil cover the reflective surface.

Cultural control as well as sprays of insecticidal soaps and certain oil sprays are acceptable for use on organically certified produce.

Routinely check field margins for whiteflies; these areas are usually infested first. Be especially alert for rapid population build up when nearby host crops are in decline. During these critical periods, check eggplant fields twice weekly. Sticky traps may be useful in detecting initial whitefly migrations into fields. If populations are high, consider a treatment. Insecticidal soaps and oils are not as effective as the other materials and require frequent application and good coverage.