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How to identify it
- The female's cover is 1 to 2 mm across (under 1/16 inch), round to oval, flat to slightly domed, and translucent light tan or grayish-brown.[1]
- At one end sits a slightly darker, yellow-brown cast skin with a stripe down its middle.[1]
- Male covers are elongate, about 1 mm long and tan to light brown, often with a greenish stripe on the cast skin.[1]
- Lift the cover of a female and the body underneath is purple; like other armored scales it produces no honeydew.[1][2]
- The scales tend to be thickest along leaf midribs and in the small pits of the fruit rind.[1]
Look-alikes
| Look-alike | How to tell them apart |
|---|---|
| Other Parlatoria scales (such as P. cinerea) | Chaff scale often shares citrus trees with P. cinerea, and other Parlatoria species can be mistaken for it; separating them takes a slide-mounted adult female under a microscope.[1] |
| Glover's scale | Glover's scale is another important armored scale of Florida citrus, but its cover is long and narrow, 2.5 to 3.5 mm, and brown, unlike chaff scale's small, round to oval, grayish-tan cover.[2][3][1] |
Where it lives
Its origin is uncertain; it now occurs throughout the tropics and subtropics, especially where citrus is grown, and only in greenhouses in colder countries. In the United States it is a citrus pest in Florida and the Gulf Coast states, has records from 18 states and the District of Columbia, living under glass in colder areas, and in California is limited to a small area of San Diego County.[1][2]
Biology and life cycle
Citrus is its favorite host, but it has been recorded on plants in 72 genera, including camellia, boxwood, aucuba, bottlebrush, elaeagnus, euonymus, ficus, jasmine, laurel, mahonia, myrtle, oleander, osmanthus, photinia, yucca, anthurium and Cymbidium orchids.[1]
It lives mainly on leaves but also on bark, twigs and fruit. On citrus it attacks branches and trunks first, then spreads to leaves and fruit.[1]
It strongly prefers shade, which makes citrus trees over 10 years old especially prone to attack, and most of the scales on fruit are in the inner, shady part of the canopy.[1]
Males and females mate, and there are three or four generations a year in California and the southeastern United States.[1]
Crawlers spread on wind and animals, and people move the scale on infested plants.[1]
Damage and signs
- Heavy infestations distort and shrivel shoots and make leaves yellow, wilt and fall, which lowers yield and can even kill the plant.[1]
- Oranges develop green spots in the rind under colonies of the scale.[1]
- Together with P. cinerea, heavy infestations have caused gumming, flaking and cracking of citrus bark that killed branches and sometimes whole trees.[1]
Health risk
The sources treat it only as a plant pest; none mentions bites or other risk to people or pets.[1][2]
Control
Prevention
Scale outbreaks most often follow repeated broad-spectrum insecticide sprays that kill natural enemies; if spraying caused the problem, switching to selective products lets the enemies recover. Check new plants, since the scale spreads on infested nursery stock.[2][1]
Traps and physical control
Look over leaves, branches and fruit in the shady inner canopy, especially leaf midribs and pits in the rind. Dead scales from earlier generations stay on the plant for months, so confirm the scales are alive before deciding to treat.[1][2]
Biological control
Parasitic wasps such as Aphytis melinus (introduced to California), Aphytis hispanicus (present in Texas) and Encarsia citrina attack chaff scale, along with lady beetles. Florida's citrus guide relies on these natural enemies as the backbone of scale management.[1][2]
Pesticides
Florida's citrus guide treats scales as occasional pests: sprays are reserved for cases where natural enemies have failed, timed for the crawler stage, and its tables list products by active ingredient.[2]
Common questions
- What are the gray flakes on the bark and fruit of my old orange tree?
- Small, flat, round to oval grayish-tan scales on shaded branches, leaves and fruit, thickest along leaf midribs and in pits of the rind, are typical of chaff scale, which favors older, shady citrus trees.[1]
- Why does my orange have green spots?
- Colonies of chaff scale cause green spotting of orange rind directly under the scales.[1]
- Does chaff scale cause sticky leaves and sooty mold?
- No. It is an armored scale, and armored scales produce no honeydew.[2]
Sources
- Naturalis Biodiversity Center (Diaspididae of the World, with USDA scale insect data), “Parlatoria pergandii (species account).” diaspididae.linnaeus.naturalis.nl/linnaeus_ng/app/views/species/taxon.php?id=113116 (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)
- Naturalis Biodiversity Center (Diaspididae of the World, with USDA scale insect data), “Lepidosaphes gloverii (species account).” diaspididae.linnaeus.naturalis.nl/linnaeus_ng/app/views/species/taxon.php?id=113092 (accessed 2026-11-09)
- iNaturalist, “Parlatoria pergandii taxon page (order and family).” www.inaturalist.org/taxa/117734 (accessed 2026-11-09)