BROWN SOFT SCALE
Coccus hesperidum L. -- Coccidae
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Kennett et al (1999) report that this soft scale is the most most cosmopolitan of the coccids attacking citrus in the world. However, it is usually not a major pest of citrus, but can show population outbreaks when natural enemy activity is curtailed by chemical treatments for other pests. Beingolea (1969) remarked that while the rarity of C. hesperidum in Peruvian citrus orchards was due to the parasitoids Metaphycus luteolus Timberlake and Coccophagus quaestor Girault, its potential to become a severe pest became evident following the use of synthetic pesticides. In South Africa C. hesperidum is attacked by more than 25 species of chalcidoids (Prinsloo 1984).
There has been realtively little attention paid to biological control of th is scale, largely because it is usually only a minor pest. The earliest efforts were made during the the early 1900's when several species of parasitoids were introduced into Western Australia (Wilson 1960). Although results were rarely reported, it seems that the scale there is kept under substantial control by both native and imported parasitoids. During the 1950's brown soft scale became a pest in Texas, and various parasitoids were introduec in 1954-1960's, but none of the five species released were established (Dean 1955, Hart et al. 1969). Dean (1955) attributed the failure of resident natural enemies to provide control to the activity of ants, but later studies showed that the drift of pesticides from adjoining crops was the principal cause (Hart et al. 1969) (also see Coquillett 1893, G. Compere1902, 1904; H. Compere 1926, 1929, 1931, 1937; Quayle 1911, 1938, Miller et al. 1936, Rivnay 1944, 1968; Bartlett & Ewert 1951, Clausen 1956, Dean & Bailey 1966, Bartlett & Ball 1966).
REFERENCES: [Additional references may be found at: MELVYL Library ]
Bartlett, B. R. & J. C. Ball. 1966. The evolution of host suitability in a polyphagous parasite with special reference to the role of parasite egg encapsulation. Ann. Ent. Soc. Amer. 9: 42-5.
Bartlett, B. R. & W. H. Ewart. 1951. Effect of parathion on parasites of Coccus hesperidum. J. Econ. Ent. 44: 344-47.
Beingolea, O. 1969. Biological control of citrus pests in Peru. Proc. 1st Intern. Citrus Symp., Riverside, Calif. 2: 827-38.
Clausen, C. P. 1956. Biological control of insect pests in the continental United States. U. S. Dept. Agric. Tech. Bull. 1139. 151 p.
Compere, G. 1902. Entomologists' report. Introduction of parasites. West. Austral. Dept. Agric. J. 6: 237-40.
Compere, G. 1904. Black scale parasite Scutellista cyanea). West Austral. Dept. Agric. J. 10: 94.
Compere, H. 1926. Descriptions of new coccid-inhabiting chalcidoid parasites (Hymenoptera). Calif. Univ. Pub. Ent. 4: 1-32.
Compere, H. 1929. Description of a new species of Coccophagus recently introduced into California. Calif. Univ. Publ. Ent. 5: 1-4.
Compere, H. 1931. A discussion of the parasites of Saissetia oleae (Bern) collected in Eritrea. Calif. Univ. Publ. Ent. 5: 247-55.
Coquillet, D. W. 1893. Report on some of the beneficial and injurious insects of California. U. S. Dept. Agric. Div. Ent. Bull. 30: 9-33.
Dean, H. A. 1955. Factors affecting biological control of scale insects on Texas citrus. J. Econ. Ent. 48: 444-47.
Dean, H. A. & J. C. Bailey. 1960. Introduction of beneficial insects for the control of citrus scale insects and mites. Rio Grande Val. Hort. Soc. J. 14: 40-6.
Hart, W. G., S. Ingle & M. Garza. 1969. Current status of brown soft scale in citrus groves of the Lower Rio Grande Valley. Ann. Ent. Soc. Amer. 62: 855-58.
Kennett, C. E., J. A. McMurtry & J. W. Beardsley. 1999. Biological control in subtropical and tropical crops. In: Bellows, T. S. & T. W. Fisher (eds.), Handbook of Biological Control: Principles and Applications. Academic Press, San Diego, New York. 1046 p
Miller, D., A. F. Clark & L. J. Dumbleton. 1936. Biological control of noxious insects and weeds in New Zealand. New Zeal. J. Sci. Technol. 18: 579-93.
Prinsloo, G. L. 1984. An illustrated guide to the parasitic wasps associated with citrus pests in the Republic of South Africa. Sci. Bull. Dept. Agric. Republic of South Africa No. 402. 119 p.
Quayle, H. J. 1911. The black scale. Calif. Agric. Expt. Sta. Bull. 223: 149-201.
Quayle, H. J. 1938. Insects of Citrus and Other Subtropical Fruits. Comstock Publ. Co., Ithaca, New York. 583 p.
Rivnay, E. 1944. The economic status of Coccus hesperidum L. and its parasites in Palestine. Bull. Soc. Fouad Ier Ent. 27: 57-77.
Rivnay, E. 1968. Biological control of pests in Israel (a review 1905-1965). Israel J. Ent. 3: 1-156.
Wilson, F. 1960. A review of the biological control of insects and weeds in Australia and Australian New Guinea. Tech. Commun. No. 1, CIBC. Commonw. Agric. Bur., Farnham Royal, Slough, England. 102 p.