University of California

Biological studies of iceplant scales, Pulvinariella Mesembryanthemi and Pulvinaria delottoi (Homoptera: Coccidae), in California


Jan O. Washburn
Gordon W. Frankie

Authors Affiliations

Jan O. Washburn was a Postdoctoral Research Associate, Department of Entomology, University of California, Berkeley; Gordon W. Frankie was Professor of Entomology, Department of Entomology, University of California, Berkeley.

Publication Information

Hilgardia 53(2):1-27. DOI:10.3733/hilg.v53n02p027. June 1985.

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Two scale species native to southern Africa, Pulvinariella mesembryanthemi and Pulvinaria delottoi (Homoptera: Coccidae), were discovered in California in the vicinity of San Francisco Bay between 1971 and 1973. Laboratory host-range tests indicate that both species are polyphagous on species of Aizoaceae, but in California these scales feed primarily on cultivated and naturalized ornamentals in the genus Carpobrotus. Some succulents in the Crassulaceae are also suitable hosts.

Pulvinariella mesembryanthemi has spread rapidly throughout the coastal regions of the state, and its current geographical range extends from San Diego County in the south to Napa County in the north. The scale is also reported from Yolo and Sacramento counties in the Central Valley. Pulvinaria delottoi is presently restricted to counties surrounding San Francisco and Monterey bays, but it is likely to spread into all areas where P. mesembryanthemi occurs. The rapid spread of these scales has probably resulted from wind dispersal of the first instars.

Pulvinariella mesembryanthemi and P. delottoi are similar morphologically, but they differ in developmental time, selection of feeding sites by crawlers, and sex ratios. The developmental time of P. mesembryanthemi is approximately half that of P. delottoi, and under field conditions north of Monterey County P. mesembryanthemi is bivoltine while P. delottoi is univoltine. In Los Angeles and Orange counties, P. mesembryanthemi has three generations per year, but when reared in warm greenhouse conditions this scale can complete a generation in 11 weeks. First instars of P. mesembryanthemi preferentially settle on young iceplant leaves; P. delottoi tends to settle on more mature leaves. This differential settling results in partial spatial segregation on host plants. Both species reproduce parthenogenetically, though males of P. mesembryanthemi are commonly produced in low numbers. In both laboratory and field populations, sex ratios were always female biased, and matings were never observed. Although males of P. delottoi were produced very infrequently under laboratory conditions, they were never encountered in field populations.

Literature Cited

Auclair J. L. Aphid feeding and nutrition. Ann. Rev. Entomol. 1963. 8:439-90. DOI: 10.1146/annurev.en.08.010163.002255 [CrossRef]

Beardsley J.W., Gonzalez R. H. The biology and ecology of armored scales. Ann. Rev. Entomol. 1975. 20:47-73. DOI: 10.1146/annurev.en.20.010175.000403 [CrossRef]

Bennassay C. Contribution a l’etude de l’influence de quelques facteurs ecologiques sur la limitation des pullulations de cochenilles-dispines. Inst. Nat. Rech. Agr. Ser. A. No. 1961. 3747:165

Blackmore S. Penetration of the host plant tissue by the stylets of the coccid Icerya seychellarum (Coccoidea: Margaroidea) on Aldabra Atoll, Indian Ocean. Atoll Res. Bull. 1981. 254:33-38.

Borchsenius N.S. New genera and species of scale insects of the family Coccidae (Homoptera: Coccoidea). (In Russian). Entomol. Obozr. 1953. 33:281-90.

Brain C. K. The Coccidae of South Africa. V. Bull. Entomol. Res. 1920. 11:41 DOI: 10.1017/S000748530004428X [CrossRef]

Brown C. E. Dispersal of the pine needle scale, Phenacaspis pinifoliae (Fitch). Can. Entomol. 1958. 90:658-90.

Collinge W. E. On the locomotion and length of life of the young of Pulvinaria vitis var. ribesiae. Sign. J. Econ. Biol. 1911. 6:139-42.

Collins L., Scott J. K. Interaction of ants, predators, and the scale insect, Pulvinariella mesembryanthemi, on Carpobrotus edulis, an exotic plant naturalized in Australia. Aust. Entomol. Mag. 1982. 8:73-78.

Cornwell P. B. Movements of the vectors of the virus diseases of cacao in Ghana. II. Wind movements and aerial dispersal. Bull. Entomol. Res. 1960. 51:175-200. DOI: 10.1017/S0007485300055048 [CrossRef]

DeLotto G. The soft scale insects of South Africa. South Afr. J. Sci. 1967. 10:793-95.

DeLotto G. The soft scales (Homoptera: Coccidae) of South Africa, IV. J. Entomol. Soc. Afr. 1979. 42:245-56.

Donaldson D. R., Moore W. S., Koehler C. S., Joos J. L. Scales threaten iceplant in Bay area. Cal. Agr. 1978. 32(10):4-7.

Douglas J. W. Note on some British Coccidae (No. 7). Entomol. Mon. Mag. 1887. 24:21-28.

Farmer L. J. The pathology of ice plant used in highway landscaping 1969. p.8. Unpublished report to the California Department of Transportation

Flanders S. E. Observations on host plant induced behavior of scale insects and their endoparasites. Can. Entomol. 1970. 102:913-26. DOI: 10.4039/Ent102913-8 [CrossRef]

Gill R. J. A new species of Pulvinaria Targioni-Tozzetti (Homoptera: Coccidae) attacking ice plant in California. Pan-Pac Ent. 1979. 55:241-50.

Hall W. J. Observations on the Coccidae of Egypt. Technical and Scientific Service Bull. No. 22. 1922. Cairo: Ministry of Agriculture, Government Press. 57p. DOI: 10.5962/bhl.title.19393 [CrossRef]

Heriot A. D. The renewal and replacement of the stylets of sucking insects during each stadium, and the method of penetration. Can. J. Res. 1934. 11:602-12. DOI: 10.1139/cjr34-117 [CrossRef]

Hill M. G. Susceptibility of Scaevola taccada (Gaertn.) Roxb. bushes to attack by the coccid Icerya seychellarum Westwood: the effects of leaf loss. Ecol. Entomol. 1980. 5:345-52.

Hodgson C. J. Some Pulvinaria species (Homoptera: Coccidae) from the Ethiopian region. J. Entomol. Soc. South Afr. 1967. 30:198-211.

Hodgson C. J. Further notes on the genus Pulvinaria Targ. (Homoptera: Coccoidea) from the Ethiopian region. J. Entomol. Soc. South Afr. 1968. 31:141-74.

McClure M. S. Colonization and establishment of the red pine scale, Matsucoccus resinosae (Homoptera: Margarodidae), in a Connecticut plantation. Environ. Entomol. 1976. 5:943-47.

McClure M. S. Competition between exotic species: scale insects on hemlock. Ecology. 1980. 61:1391-401. DOI: 10.2307/1939048 [CrossRef]

McLaren I. W. A comparison of the population growth potential in California red scale, Aonidiella aurantii (Maskell), and yellow scale, A. citrina (Coquillet), on citrus. Aust. J. Zool. 1971. 19:189-204.

Milne W. M. Insecticidal vs. natural control of white wax scale (Gascardia destructor) at Kenthurst, New South Wales, Australia during 1972-1973. J. Aust. Entomol. Soc. 1981. 20:167-70.

Moore W. S., Koehler C. S., Joos J. L., Donaldson D. R., Cassidy D. V., Gill R. J. Ice plant scale insects. Coop. Ext. Leaflet 21084. 1979. University of California. 7p.

Neunschwander P., Paraskakis M. Distribution and population dynamics of Saissetia oleae (Homoptera: Coccidae) within the canopy of the olive tree. Z. Angew. Entomol. 1980. 90:366-78.

Newberry D. McC. Infestation of the coccid, Icerya seychellarum (Westw.), on the mangrove Avicennia marina (Forsk.) Vierh. on Aldabra Atoll with special reference to tree age. Oecologia (Berl.). 1980. 45:325-30.

Nur U. Meiotic parthenogenesis and heterochromatization in a soft scale, Pulvinaria hydrangeae (Coccoidea: Homoptera). Chrom. (Berl.). 1963. 14:123-39.

Nur U. Diploid arrhenotoky and automictic thelytoky in soft scale insects (Lecaniidae: Coccoidea: Homoptera). Chrom. (Berl.). 1972. 39:381-401. DOI: 10.1007/BF00326174 [CrossRef]

Nur U., Blackman R. L., Hewitt G. M., Ashburner M. Evolution of unusual chromosome systems in scale insects (Coccoidea: Homoptera). Insect Cytogenetics, Symposia of the Royal Entomol. 1980. Oxford: Blackwell Scientific Publications. p. 97-117. Soc. of London 10, eds

Oda T. Studies on the dispersion of the mulberry scale Pseudaulacaspis pentagona. (In Japanese, English summary) Jap. J. Ecol. 1963. 13:41-46.

Pesson P. Description du male de Pulvinaria mesembryanthemi Vallot et observations biologiques sur cette espece. (Hemiptera: Coccidae). Ann. Soc. Entomol. France. 1941. 110:71-77.

Pinnock D. E., Brand R. J., Milstead J. E. The field persistence of Bacillus thuringiensis spores. J. of Invert. Path. 1971. 18:405-11.

Podder H. I., Bar-Zacay R., Rosen D. Population dynamics of the Mediterranean black scale, Sassetia oleae (Olivier), on citrus in Israel. 1. A partial life table. J. Entomol. Soc. South Afr. 1979. 42:257-66.

Quayle H. J. Locomotion of certain young scale insects. J. Econ. Entomol. 1911. 4:301-06.

Quayle H. J. Dispersion of scale insects by the wind. J. Econ. Entomol. 1916. 9:486-92.

Quintana F. J. Pulvinaria mesembryanthemi (Vallot), (Homoptera: Sternorrhyncha) nueva cochinilla para la fauna Argentina y sus zooparasitos. LaPlata Univ. Nac., Facultad de Agron. Rev. 1956. 32(1):75-110.

Schultz P. B. Delayed hatching of Japanese wax scale, Ceroplastes ceriferus (Homoptera: Coccidae) in locations strongly affected by marine winds. J. N.Y. Entomol. Soc. 1980. 88:70-71.

Southwood T. R. E. Migration of terrestrial arthropods in relation to habitat. Biol. Rev. 1962. 37:171-214. DOI: 10.1111/j.1469-185X.1962.tb01609.x [CrossRef]

Stephens G. R., Aylor D. E. Aerial dispersal of red pine scale, Matsucoccus resinosae (Homoptera: Margarodidae). Environ. Entomol. 1978. 7:556-63.

Stoetzel M. B., Davidson J. A. Life history variations of the obscure scale on pin oak and white oak in Maryland. Ann. Entomol. Soc. Am. 1973. 66:308-11.

Tassan R. L., Hagen K. S., Cassidy D. V. Imported natural enemies established against ice plant scales in California. Cal. Agr. 1983. 36(9-10):16-17.

Vallot J. N. Nouvelle especes de Cochenilles 1829. pp.30-33. Acad. des Sci., Arts et Belles Lettres de Dijon, Compt. Rend. (1828-1829):

Washburn J. O., Frankie G. W. Dispersal of a scale insect, Pulvinariella mesembryanthemi (Homoptera: Coccoidea), on iceplant in California. Environ. Entomol. 1981. 10:724-27.

Washburn J. O., Washburn L. Active aerial dispersal of minute wingless arthropods: exploitation of boundary layer velocity gradients. Science. 1984. 223:1088-89. DOI: 10.1126/science.223.4640.1088 [CrossRef]

Webb J., Moran V. C. The influence of the host plant on the population dynamics of Acizzia russellae (Homoptera: Psyllidae). Ecol. Entomol. 1978. 3:313-21.

Willard J. R. Dispersal of California red scale (Aonidiella aurantii (Maskell)) (Homoptera: Diaspididae) in relation to weather variables. J. Aus. Entomol. Soc. 1976. 15:395-404.

Washburn J, Frankie G. 1985. Biological studies of iceplant scales, Pulvinariella Mesembryanthemi and Pulvinaria delottoi (Homoptera: Coccidae), in California. Hilgardia 53(2):1-27. DOI:10.3733/hilg.v53n02p027
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