Citrus Whitefly
Egg -Almost microscopic, the egg is pale yellow-green.
Crawler -Tiny and pale green, the crawler has six legs, two antennae, and two red eyespots.
Nymph -The flattened nymph is pale green and scalelike.
Host Plants -The citrus whitefly has been reported on 38 genera of evergreen and deciduous plants. Preferred host plants include chinaberry, all varieties of citrus, gardenia, privet, prickly ash, and Japanese persimmon.
Damage -Adult citrus whiteflies damage their host plants directly by ovipositing and feeding. Immature citrus whiteflies suck much sap from the leaves, although no quantitative work has determined exactly how much damage this causes.
The honeydew excreted by the feeding whiteflies provides an excellent medium for the sooty mold fungus Capnodium citri. It coats the leaves and stems of infested plants, shading them from sunlight. The number, size, and quality of citrus fruit are reduced; heavily infested gardenias, black with sooty mold, eventually drop their leaves prematurely.
Life History -Each female citrus whitefly may lay up to 125 eggs, which are partially inserted into the lower leaf surface. In heavy infestations, eggs may be so numerous that leaves are malformed and growth is impaired. The eggs hatch in 6 to 21 days, and tiny, pale-green crawlers move about the plant seeking a place to feed. When they insert their long, threadlike mouthparts into the lower leaf surface, they become immobile. After the first molt, legs and antennae are lost. After two additional molts, the pupae form. The adults finally emerge from T-shaped splits in the pupal skins. There are three broods each year in Alabama and Florida. Summer broods require about 2 months for development; the last brood overwinters in the immature stage.
At least three species of lady beetles are known to feed on citrus whitefly crawlers and nymphs, but they are seldom numerous enough to effect real control. A tiny wasp has recently been introduced into Florida to help control citrus whiteflies.
Insecticides should be applied in late spring before the emergence of first-generation adult whiteflies. The spray should be directed to the undersides of the leaves. For specific chemical controls, see the current state extension service recommendations.