Common Name: Citrus blackfly
Scientific Name: Aleurocanthus woglumi Ashby
Description: Adult stages have are slate blue wings with a white band across the center. The head and abdomen are bright red and the antennae and legs are white.
Life Cycle: Mated females lay yellowish-brown eggs in a spiral pattern on the underside of leaves. Tiny “crawlers” with antennae and six short legs hatch from eggs. Their bodies are white to brown and flattened, oval in shape, with red eye- spots and 2 long spines on their backs. Upon settling on the leaf surface, the crawler stage molts to a non-motile second stage (instar) which appears dull black with patches of yellow and spines on the upper body surface. Development continues to a larger, third larval stage and then to an oval, shiny black, spiny pupal stage marked with a fringe of white wax around the margin. Adults emerge from a T-shaped crack on the back of the pupa. Development from egg to adult can occurs in 60 to 120 days, depending on temperature.
Habitat, Food Source(s), Damage: Host plants include all species of citrus, mango, avocado, coffee, pear, plum, pomegranate, guava and ash. Citrus blackfly adults and immatures feed on the underside of host plant leaves. They remove large quantities of sap which is excreted by immature stages as “honeydew”, which then serves as a substrate on which a black-colored sooty mold fungus develops.
Pest Status, Damage: Actually a species of whitefly, but called a “blackfly” because of its body color. It should not be confused with black flies (Diptera: Simuliidae), which are true flies; has been a pest of citrus, dooryard plants and nursery crops in south Texas since the 1950’s; medically harmless.
Heavily infested trees become unsightly because of black-coated leaves and fruit (from sooty mold). Photosynthesis and fruit production are reduced because light can not penetrate the blackened fungus layer to the leaf surface. High numbers flying adults associated with heavily infested host plants can be a nuisance.
Literature: French et al. 1989; Huffman 1996.