(Cockerell, 1893)
Diagnosis
Scale cover of adult female in life subcircular to elongate oval, 2.0-3.0 mm long, moderately convex, with well-defined curved ridges across the secretionary cover, which often has parallel sides; cover blackish but with a purplish-brown or bluish grey tinge; exuviae terminal or subapical, brownish black, the first instar exuviae often forming a crater in the centre of the more convex second instar exuviae PSBOWL.jpg . Ventral scale well developed (Miller et al., 1984). Scale cover of male similar to that of female but smaller (1 mm long), with brown or black, terminal or subapical exuviae (Dekle, 1976) PSBOWL.jpg .
Body of slide-mounted adult female pyriform to elongate oval initially, later becoming parallel sided and 2-4x as long as wide; remaining membranous except front of head, which may become sclerotized with maturity; front of head rounded, without any protruberance PSBOWS.jpg . Pygidium base broad but apex acute, subtended by an angle of less than 90°; however, the width of the pygidium is highly variable (Miller et al., 1984). Lateral margins of pygidium rather concave and sclerotized; with three pairs (possibly four) of short, wide lobes; paraphyses present lateral to, as well as between, third lobes; plates present only in interlobular spaces; fewer than 12 dorsal submarginal macroducts present on each side of pygidium PSBOWP1.jpg .
Host range
Pseudischnaspis bowreyi has been recorded from hosts belonging to 10 plant families (Borchsenius, 1966). The species is polyphagous but shows a slight preference for orchids, bromeliads and Agave. Hosts include species of: Agave, Aloe, Annona, Aspidosperma, Bromeliaceae, Camellia, Carya, Castela, Cattleya, Ceiba, Citrus, Coccoloba, Copernicia, Dracaena, Epidendrum, Eucalyptus, Euphorbia, Ficus, Hedera, Hibiscus, Hylocereus, Jacaranda, Jasminum, Mangifera, Maytenus, Myrica, Musa, Nerium, Olea europaea, Oncidium, Orchidaceae, Nolina, Passiflora edulis, Persea americana, Phoenix, Prunus, Psidium, Pyrus, Rollinia, Rosa, Salix spp., Spondias, Theobroma, Tillandsia, Vismia, Vitis, Yucca and Ziziphus.
Affected plant stages: vegetative growing, flowering and fruiting stages
Affected plant parts: on bark and leaves
Biology and ecology
The biology and ecology of P. bowreyi have not been studied. Crawlers are the primary dispersal stage and move to new areas of the plant or are dispersed by wind or animal contact. Mortality due to abiotic factors is high in this stage. Dispersal of sessile adults and eggs occurs through human transport of infested plant material.
Economic impact
Dekle, 1976, mentioned that P. bowreyi is not an economic pest in Florida; however, its host range suggests that, if introduced to countries where no suitable natural enemies occur, this species could be damaging to economically important plants.
Detection and inspection methods
Examine leaves and bark of the host-plants listed above, for subcircular to elongate oval, moderately convex scale covers, with well-defined curved ridges across the secretionary cover, which often has parallel sides; cover blackish but with a purplish-brown or bluish grey tinge; exuviae terminal or subapical, brownish black.
Natural enemies
The natural enemies of P. bowreyi have not been studied.
Distribution
See Pseudischnaspis bowreyi distribution.
Microscopic examination of slide-mounted adult females is required for authoritative identification to species.
Some species of Acutaspis have a pygidium rather similar to Pseudischnaspis bowreyi, but in P. bowreyi the body is elongate (more than twice as long as wide) PSBOWS.jpg, whereas the body in Acutaspis spp. is broadly pyriform to heart-shaped (less than twice as long as wide ) ACPERS.jpg.
Newly matured adult females of P. bowreyi are indistinguishable from some species of Melanaspis; this is discussed in detail by Miller et al., 1984. The elongation of the body with maturity makes Pseudischnaspis distinct from Melanaspis.
Pseudischnaspis acephala Ferris (flat-headed scale) is very similar to P. bowreyi but differs in having the front of the head usually distinctly flattened, a total of 8-13 perivulvar pores, and a distance between the posterior edge of the anal opening and the base of the median lobes of 59-123 µm. In contrast, P. bowreyi has a rounded front margin PSBOWS.jpg , a total of 13-31 perivulvar pores, and a distance between the posterior edge of the anal opening and the base of the median lobes of 91-143 µm PSBOWP1.jpg . Pseudischnaspis acephala is a relatively polyphagous species that has been recorded from Mexico, Panama, Colombia and Peru on leaf undersides and fruits of species of Anacardium, Chamaedorea, Citrus spp., Cocos nucifera, Coffea, Mangifera indica, Narcissus and Persea (Miller et al., 1984). The scale cover is very similar to that of P. bowreyi in life. Taxonomic illustrations of both species are provided by Miller et al., 1984. The presence or absence of notches on the median lobes is highly variable in P. acephala (Miller et al., 1984).
Comments
Pseudischnaspis bowreyi originated in the Neotropics, and is still confined to the Western Hemisphere. It has not been recorded from Europe, Asia, Africa, Australia, or from the Pacific Islands. Hodgson and Hilburn, 1991, remark that the species does not appear to be established in Bermuda.
Western Hemisphere
Argentina: frequent (Claps et al., 2001a)
Catamarca: present, no further details (Claps et al., 2001a)
Chaco: present, no further details (Claps et al., 2001a)
Jujuy: present, no further details (Claps et al., 2001a)
La Rioja: present, no further details (Claps et al., 2001a)
Santa Fe: present, no further details (Claps et al., 2001a)
Santiago del Estero: present, no further details (Claps et al., 2001a)
Tucumán: present, no further details (Claps et al., 2001a)
Barbados: present, no further details (Miller et al., 1984; Bennett and Alam, 1985)
Belize: present, no further details (Miller et al., 1984)
Bolivia: present, no further details (Nakahara, 1982)
Brazil
Bahia: present, no further details (Claps et al., 2001a)
Pará: present, no further details (Claps et al., 2001a)
Paraíba: present, no further details (Claps et al., 2001a)
Pernambuco: present, no further details (Claps et al., 2001a)
Rio de Janeiro: present, no further details (Claps et al., 2001a)
Rio Grande do Sul: present, no further details (Claps et al., 2001a)
Santa Caterina: present, no further details (Claps et al., 2001a)
Sao Paulo: present, no further details (Claps et al., 2001a)
Chile
Tarapacá: present, no further details (Claps et al., 2001a)
Colombia: present, no further details (Miller et al., 1984; Kondo, 2001)
Cuba: present, no further details (Miller et al., 1984)
Dominican Republic: present, no further details (Nakahara, 1982)
Ecuador: present, no further details (Miller et al., 1984)
Greater Antilles: present, no further details (Kondo, 2001)
Guatemala: present, no further details (Miller et al., 1984)
Honduras: present, no further details (Miller et al., 1984)
Jamaica: present, no further details (Miller et al., 1984; Kondo, 2001)
Mexico: present, no further details (Miller et al., 1984; Miller, 1996; Kondo, 2001)
Nicaragua: present, no further details (Miller et al., 1984)
Panama: present, no further details (Miller et al., 1984)
Peru: present, no further details (Miller et al., 1984)
Puerto Rico: present, no further details (Miller et al., 1984)
St Croix: present, no further details (Miller et al., 1984)
St Thomas: present, no further details (Miller et al., 1984)
Trinidad: present, no further details (Miller et al., 1984; Kondo, 2001)
USA
Florida: present (Miller et al., 1984)
Missouri: under glass (Miller et al., 1984)
New York: present (Miller et al., 1984)
Venezuela: present, no further details (Miller et al., 1984)