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How to identify it
- The female's cover is 1.5 to 2.5 mm long, mussel-shaped and slightly domed, white to gray, with a yellowish-brown cap (the shed skins) at the narrow end.[1]
- Male covers are snow white, long and parallel-sided, with three strongly raised ridges running their length.[1]
- It usually sits on twigs, branches and trunks, and only occasionally on leaves and fruit; in citrus it generally lives on the smaller limbs.[1][2]
- Like other armored scales, its cover can be lifted off the body, and it produces no honeydew.[2]
Look-alikes
| Look-alike | How to tell them apart |
|---|---|
| Fern scale (Pinnaspis aspidistrae) | Very hard to tell apart in the field because cover color is not a reliable difference. In Florida citrus, fern scale tends to form small round colonies of males on leaves and fruit, with a single female off to one side.[1][2] |
| Citrus snow scale (Unaspis citri) | Its numerous white male nymphs cannot be told apart from lesser snow scale males; look at the females instead. Citrus snow scale females are larger, oyster-shaped and purple with a ridge down the middle.[2] |
Where it lives
Probably native to the Oriental region, lesser snow scale now occurs throughout tropical and subtropical regions and lives only in greenhouses in temperate countries. U.S. records include Alabama, Florida, Georgia, Hawaii, Louisiana, Mississippi and Texas, and it is widespread in Florida and Hawaii.[1]
Biology and life cycle
Both males and females occur, and there are several generations a year. Each female lays her eggs under her cover and dies once she has finished.[1]
Crawlers hatch and move off to find feeding sites on stems and leaves; males settle near the females. In Cuba, males took about 23 days and females about 45 days to develop.[1]
It is highly polyphagous, recorded from more than 170 plant genera in 27 families. Palms, plants in the lily family and orchids are favored, and hosts include citrus, hibiscus, coconut, mango, banana, cassava, agave, aloe and camellia.[1]
It often travels on plant material: in California it is commonly intercepted on coconut husks in quarantine and on ti and ginger plants shipped from Hawaii.[1]
Damage and signs
Health risk
The sources treat it only as a plant pest; none mentions bites or any risk to people or pets.[1][2]
Control
Prevention
Scale outbreaks usually follow weather that disrupts natural enemies, moving the pest to places without them, or repeated broad-spectrum insecticide sprays while natural enemies are active; avoiding those sprays helps keep scales down.[2]
Inspect leaves, bark and fruit of host plants for white to gray, mussel-shaped covers with a yellowish-brown cap at the narrow end.[1]
Biological control
In Florida citrus, lady beetles, parasitic wasps and fungal diseases normally keep scale insects in check, so scales are not treated as key pests. Many Aphytis and Encarsia wasps and Chilocorus lady beetles attack lesser snow scale.[2][1]
When to call a professional
Because lesser snow scale and fern scale look so alike, a sure identification needs a slide-mounted adult female examined under a microscope.[1]
Common questions
- What is the white crust on my citrus twigs?
- White, ridged male covers in large numbers on twigs and limbs are often snow scales. Lesser snow scale generally lives on the smaller limbs of citrus, while citrus snow scale, with purple, oyster-shaped females, tends to infest the trunk and scaffold limbs.[2]
- Can lesser snow scale kill a plant?
- Heavy infestations can cause wilting, leaf drop and dieback of stems or even the entire plant.[1]
- Does lesser snow scale make honeydew?
- No. It is an armored scale, and armored scales produce no honeydew, unlike soft scales.[2]
Sources
- Naturalis Biodiversity Center (Diaspididae of the World, with USDA scale insect data), “Diaspididae of the World 2.0: Pinnaspis strachani.” diaspididae.linnaeus.naturalis.nl/linnaeus_ng/app/views/species/taxon.php?id=113122 (accessed 2026-11-09)
- University of Florida IFAS Extension (EDIS), “2026-2029 Florida Citrus Production Guide: Soft-Bodied Insects Attacking Foliage and Fruit (CG004).” journals.flvc.org/edis/article/view/133504 (accessed 2026-11-09)
- University of Florida IFAS Extension (EDIS), “Mango Pests and Beneficial Insects (ENY-413/IG073, 2017).” journals.flvc.org/edis/article/view/138135 (accessed 2026-11-09)
- iNaturalist, “Pinnaspis strachani taxon page (order and family).” www.inaturalist.org/taxa/330230 (accessed 2026-11-09)