Hostname: page-component-7479d7b7d-fwgfc Total loading time: 0 Render date: 2024-07-11T09:27:39.508Z Has data issue: false hasContentIssue false

Laboratory and field evaluation of cocoa progenies for resistance to mealybug vectors (Hemiptera: Pseudococcidae) of swollen shoot virus

Published online by Cambridge University Press:  10 July 2009

S. Firempong
Affiliation:
Cocoa Research Institute of Ghana, P.O. Box 8, Akim Tafo, Ghana

Abstract

Resistance of cocoa to Planococcoides njalensis (Laing) was assessed in the laboratory in Ghana by rearing the mealybug from birth until death on seven cocoa progenies, and determining survivorship, duration of reproduction, gross reproductive rate and live weight. Field evaluation was by sampling both P. njalensis and Planococcus citri (Risso) on the tree trunks and in terminal buds. Progenies 85D/176A × M7/537 and T12/116 × T62/977 were judged the most resistant using the parameters determined in the laboratory. The resistance factor is attributed to antibiosis. The mealybug populations in the field did not show any significant differences among the progenies, but the trend followed the laboratory results. It is suggested that the laboratory method reported here is adequate in assessing resistance, has the advantage of being faster than the field technique and can be used in combination with existing methods for assessing cocoa progenies for resistance to the virus disease.

Type
Original Articles
Copyright
Copyright © Cambridge University Press 1984

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bigger, M. (1975). Susceptibility of two cocoa progenies to attack by insect species. I.—Proportion of trees infested.—Exp. Agric. 11, 187192.CrossRefGoogle Scholar
Bigger, M. (1976). Mealybug studies.—Rep. Cocoa Res. Inst., Ghana 197374, 101118.Google Scholar
Bigger, M. (1981). The relative abundance of the mealybug vectors (Hemiptera: Coccidae and Pseudococcidae) of cocoa swollen shoot disease in Ghana.—Bull. ent. Res. 71, 435448.CrossRefGoogle Scholar
Campbell, C. A. M. (1975). The distribution of mealybug vectors of CSSV within trees.— pp. 6771in Kumar, R. (Ed.). Proceedings of the 4th Conference of West African Cocoa Entomologists,Zoology Department, University of Ghana,Legon, Ghana,9th–13th December, 1974202 pp. Legon, Ghana, Zool. Dep., Univ. Ghana.Google Scholar
Cornwell, P. B. (1958). Movements of the vectors of virus diseases of cacao in Ghana. I.—Canopy movement in and between trees.—Bull. ent. Res. 49, 613629.CrossRefGoogle Scholar
Cotterell, G. S. (1943). Entomology. Swollen-shoot virus.—Rep. cent. Cocoa Res. Stn, Tafo 193842, 5154.Google Scholar
Entwistle, P. F. (1958). Mealybugs in relation to cocoa in Ghana. I.—Their structure and life history.—Ghana Fmr 2, 1215.Google Scholar
Entwistle, P. F. (1972). Pests of cocoa.—779 pp. London, Longman.Google Scholar
Firempong, S. (1981). A method of rearing the mealybug Planococcoides njalensis on cocoa seedlings.—Rev. Theobroma 11, 229232.Google Scholar
Firempong, S. (1982). The performance of Planococcoides njalensis (Homoptera: Pseudococcidae) on some cocoa cultivars.—pp. 100101in Tests of agrochemicals and cultivars, 3.—Ann. appl. Biol. 100 (suppl.), 112 pp.Google Scholar
Kennedy, G. G. (1976). Host plant resistance and the spread of plant viruses.—Environ. Entomol. 5, 827832.CrossRefGoogle Scholar
Legg, J. T. & Lockwood, G. (1975). Cocoa swollen shoot disease.—Rep. Cocoa Res. Inst., Ghana 197273, 45.Google Scholar
Legg, J. T. & Lockwood, G. (1981). Resistance of cocoa to swollen-shoot virus in Ghana. I. Field trials.—Ann. appl. Biol. 97, 7589.CrossRefGoogle Scholar
Leston, D. (1970). Entomology of the cocoa farm.—A. Rev. Ent. 15, 273294.CrossRefGoogle Scholar
Magnin, J. (1953). Développement et mode de reproduction de Pseudococcus njalensis Laing.—Agron. trop., Nogent 8, 292299.Google Scholar
Owusu, G. K. (in press). The cocoa swollen shoot virus problem in Ghana.—in Plumb, R. T. & Thresh, J. M. (Eds.). Plant virus epidemiology.—Oxford, Blackwell.Google Scholar
Roivainen, O. H. (1969). Mealybug studies.—Rep. Cocoa Res. Inst., Ghana 196768, 4344.Google Scholar
Roivainen, O. (1976). Transmission of cocoa viruses by mealybugs (Homoptera: Pseudococcidae).—J. scient. agric. Soc. Finland 48, 203304.Google Scholar
Strickland, A. H. (1951). The entomology of swollen shoot of cacao. II.—The bionomics and ecology of the species involved.—Bull. ent. Res. 42, 65103.CrossRefGoogle Scholar
Thresh, J. M. (1958). The spread of virus disease in cacao.—Tech. Bull. W. Afr. Cocoa Res. Inst. no. 5, 36 pp.Google Scholar