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How to identify it
- Adults are tiny whiteflies that look slate blue: within a day of emerging they are coated in a fine wax powder that gives them that color.[1]
- Eggs are laid in spirals on the undersides of leaves. Each female lays two or three spirals in her 10 to 14 days of life.[1]
- The nymphs are black and spiny. The first stage is brown with two glassy filaments curving over its back; later stages are dark brown, then shiny black with stout spines.[1]
- The last nymphal stage (the 'pupa case') is oval, shiny black and edged with a fringe of white wax, about 1 to 1.25 mm long. Adults leave through a T-shaped split at the front end.[1]
Look-alikes
| Look-alike | How to tell them apart |
|---|---|
| Citrus whitefly | Citrus whitefly adults are all white, and their nymphs are hard to see. Citrus blackfly adults are slate blue, its eggs sit in spirals, and its nymphs are black and spiny.[1] |
| Woolly whitefly | Woolly whitefly adults are white, and the females lay their eggs in a circle while surrounded by waxy filaments.[1] |
| Cloudywinged whitefly | Cloudywinged whitefly adults are white with a darkened area at the end of each wing.[1] |
Where it lives
Native to Asia, it reached the Western Hemisphere in Jamaica in 1913. It was eradicated from Key West after a 1934 find, turned up again in Fort Lauderdale in 1976 and has since spread from north-central through south Florida. The European Union regulates Aleurocanthus whiteflies on citrus, and climate modeling suggests its potential range there could move north and to higher elevations by 2050.[1][3][4]
Biology and life cycle
It has more than 300 host plants, including pear, rose and grape, but citrus is by far the best host for large populations.[1][3]
Eggs hatch in 7 to 10 days. The young pass through three spiny nymphal stages and a pupa-like fourth stage, and the full life cycle takes 45 to 133 days depending on temperature.[1]
South Florida has about six generations a year. Whiteflies on citrus depend on new growth and are active mainly while trees are flushing.[1][2]
Damage and signs
Health risk
The sources treat it only as a plant pest; none mentions bites, stings or other risk to people or pets.[1][2][3]
Control
Prevention
Avoid sprays that undercut its natural controls: copper fungicides also inhibit 'friendly fungi', which leads to more whiteflies, and more than one sulfur application a year can harm the parasitic wasps.[1]
Keep them out
Plants for planting and cut flowers or branches are the main pathways for Aleurocanthus whiteflies to enter new regions, and researchers advise against importing untreated host material into areas where the blackfly could establish.[3][4]
Biological control
Two parasitic wasps, Encarsia perplexa and Amitus hesperidum, are its most effective enemies in Florida. Amitus works best on dense populations in cool, humid seasons, while Encarsia, a better searcher, holds blackfly at lower levels. Thanks to them it normally stays at very low numbers and rarely requires treatment.[1][2]
Pesticides
Florida growers seldom spray just for whiteflies; sprays aimed at scale insects also control them, and spray oil is used mainly to wash off sooty mold. Recommendations for dooryard trees differ from those for commercial groves, so use the management guide for your situation.[1]
Common questions
- Why are my citrus leaves black and sticky?
- Honeydew from sap-sucking insects grows black sooty mold. If you find slate-blue whiteflies, spiral egg clusters or spiny black nymphs under the leaves, citrus blackfly is a likely cause.[1]
- Is the citrus blackfly a fly?
- No. Despite the name it is a whitefly; the adult's slate-blue color earned it the name blackfly.[1]
- Should I spray citrus blackfly on my backyard tree?
- Usually not. Parasitic wasps normally keep it at low numbers in Florida, and some sprays, such as copper and repeated sulfur, can make whitefly problems worse by harming its natural enemies.[1][2]
Sources
- University of Florida IFAS Extension (EDIS), “Citrus Blackfly, Aleurocanthus woglumi Ashby (Featured Creatures EENY-042, R. Nguyen, A.B. Hamon and T.R. Fasulo; revised 2010).” journals.flvc.org/edis/article/view/138691 (accessed 2026-11-09)
- University of Florida IFAS Extension (EDIS), “2026-2029 Florida Citrus Production Guide: Soft-Bodied Insects Attacking Foliage and Fruit (CPG vol. 1 ch. 24).” journals.flvc.org/edis/article/view/133504 (accessed 2026-11-09)
- European Food Safety Authority (EFSA Journal), “EFSA Panel on Plant Health. Pest categorisation of Aleurocanthus spp. EFSA Journal 16(10):5436 (2018) (abstract).” doi.org/10.2903/j.efsa.2018.5436 (accessed 2026-11-09)
- Elsevier (Current Opinion in Insect Science), “Lemic D et al. Global change and adaptive biosecurity: managing current and emerging Aleurocanthus woglumi threats to Europe. Current Opinion in Insect Science 62:101164 (2024) (abstract).” doi.org/10.1016/j.cois.2024.101164 (accessed 2026-11-09)
- iNaturalist, “Aleurocanthus woglumi taxon page (order and family).” www.inaturalist.org/taxa/907079 (accessed 2026-11-09)