Saissetia

Deplanche, 1859

soft scales, black scales

Saissetia is a of (: ) containing at least four described . The genus includes economically important pests, notably Saissetia oleae (black ) and Saissetia coffeae (hemispherical scale), which attack citrus, olive, coffee, and numerous ornamental plants. Saissetia species are phloem-feeding insects that produce , facilitating associations and growth. Several species have been globally through trade in infested nursery plants.

Saissetia coffeae from CSIRO by Unknown authorUnknown author. Used under a Public domain license.

Cycad Aulacaspis scale - 33708393355 by Plant pests and diseases. Used under a CC0 license.

Cycad Aulacaspis scale - 30555605666 by Plant pests and diseases. Used under a CC0 license.

Pronunciation

How to pronounce Saissetia: //ˌsaɪˈsiːʃiə//

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Identification

females of Saissetia are characterized by a convex, dome-shaped or hemispherical body with a smooth or slightly wrinkled surface. The body is often dark to black in mature specimens. A diagnostic feature is the presence of stigmatic arranged in groups, with the number and arrangement varying among . Saissetia oleae typically exhibits a characteristic H-shaped ridge on the dorsal surface. Saissetia coffeae is distinguished by its more uniformly rounded, hemispherical shape and -brown to dark brown coloration. The can be separated from similar genera such as Coccus and Parasaissetia by the structure of the stigmatic cleft and the arrangement of pregenital and setae. A key to Chinese Saissetia species has been published based on adult female .

Images

Habitat

Saissetia occur on the woody stems and leaves of plants. They are found in subtropical and tropical agroecosystems, including citrus groves, olive orchards, coffee plantations, and ornamental nurseries. In Florida, Saissetia oleae has been recorded on citrus, cultivated olive, avocado, and landscape plants. Saissetia miranda has been documented on fig trees (Ficus carica) in northern Mexico and as a new record on hemp in Florida. The has also been recorded from Lithocarpus uvariifolius in Yunnan, China.

Distribution

The has a distribution through human-mediated . Saissetia oleae, originally from South Africa, is now present worldwide including Europe, Asia, Africa, Australasia, North America, Central America, the Caribbean, and South America. Saissetia coffeae has a broad tropical and subtropical distribution. Saissetia miranda occurs in the Americas including Mexico and the United States (Florida). Saissetia neglecta has been recorded from Africa.

Seasonality

In Mediterranean climates, Saissetia oleae typically has one per year, with peak in spring. In warmer regions, multiple overlapping generations may occur. On Corfu, Greece, periods indicate S. oleae availability from spring through autumn: Metaphycus helvolus April–July and November–December; M. lounsburyi flies April–August; and Scutellista cyanea flies August–October.

Diet

Phloem sap. Saissetia feed by inserting into vascular tissue and extracting sap, depriving the plant of nutrients and photosynthates.

Host Associations

Olea europaea - primary of Saissetia oleae
Citrus - major of Saissetia oleae
Coffea - of Saissetia coffeae
Ficus carica - of Saissetia miranda
Persea americana - of Saissetia oleae in Florida
Lithocarpus uvariifolius - of Saissetia puerensis
Cannabis sativa - new record for Saissetia miranda in Florida

Life Cycle

Saissetia exhibit with females. are laid under the female's body and protected by the waxy . First- () disperse to find feeding sites. Development proceeds through four instars in females; males develop through four nymphal instars followed by a prepupal and pupal stage. The duration varies with temperature and . For Saissetia oleae reared at 23°C, development times differ based on host substrate: 19.4 days on potato sprouts versus 15.1 days on Nerium oleander for associated Metaphycus helvolus, indicating host-mediated effects on development.

Behavior

females are , remaining permanently attached to plants after settling. First- are the primary stage. Saissetia excrete , which attracts tending that protect from and transport crawlers to new feeding sites. This with ants reduces effectiveness.

Ecological Role

As phloem-feeding , Saissetia act as stressors and through their feeding wounds. Their production supports growth, reducing . The serves as for diverse complexes (, , , ), contributing to complexity. In some systems, Saissetia are regulated by agents, with rates reaching 54.9–72.9% in Mexican fig orchards.

Human Relevance

Saissetia are significant agricultural and horticultural pests. Saissetia oleae (black ) is a major pest of citrus and olives globally, causing yield losses through direct feeding and . Saissetia coffeae (hemispherical scale) damages coffee, guava, and citrus. Saissetia miranda (Mexican black scale) has emerged as a pest of fig and a new concern for hemp in Florida. Management relies on using such as Metaphycus helvolus, M. lounsburyi, and M. anneckei; exclusion to improve parasitoid access; and insecticidal treatments when biological control fails.

Similar Taxa

CoccusBoth are with convex body shape; Saissetia distinguished by stigmatic arrangement and presence of H-shaped ridge in S. oleae
ParasaissetiaClosely related formerly confused with Saissetia; separated by morphological details of stigmatic cleft and
CeroplastesBoth produce waxy coverings; Ceroplastes has more elaborate waxen ornamentation and different body shape
ProtopulvinariaSimilar hemispherical shape; distinguished by internal and setal characteristics

More Details

Parasitoid Complex

Saissetia diverse . Saissetia oleae on Corfu is attacked by Metaphycus helvolus, M. lounsburyi, M. affinis stanleyi, Scutellista cyanea, and Moranila californica. Saissetia miranda on figs in Mexico supports Scutellista caerulea, Metaphycus anneckei, Cheiloneurus sp., Baryscapus sp., and Signiphora bifasciata. The UCR collection contains numerous specimens reared from Saissetia, including Gahaniella saissetiae and Taftia saissetiae, indicating historical importance in research.

Taxonomic History

The was established by Deplanche in 1859. -level relies primarily on female , with males and immatures poorly known for several species. A new species, Saissetia puerensis, was described from China in 2018, bringing the total to at least five described species.