Hostname: page-component-7479d7b7d-q6k6v Total loading time: 0 Render date: 2024-07-09T00:00:25.107Z Has data issue: false hasContentIssue false

Feeding by Distantiella theobroma (Dist.) (Heteroptera, Miridae) on Cocoa. I.—The effects of water stress in the plant

Published online by Cambridge University Press:  10 July 2009

D. G. Gibbs
Affiliation:
International Capsid Research Team, Cocoa Research Institute, New Tafo, Ghana
A. D. Pickett
Affiliation:
International Capsid Research Team, Cocoa Research Institute, New Tafo, Ghana

Extract

Data were obtained on survival and development of larvae of Distantiella theobroma (Dist.) on cocoa seedlings maintained under three water régimes, high (HW), intermediate (IW) and low (LW). Recorda were taken of plant growth and damage by feeding. The water régimes of some plants were reversed in the latter part to the experiment.

Larvae soon completed development on HW plants, but on LW plants a large number died, possibly because they were unable to take up fluid fast enough to offset loss by evaporation. There was intermediate mortality on IW plants.

Larvae took longer to develop on IW than on HW plants, probably because they imbibed nutrients at a reduced rate.

More larvae survived on LW plants that were regenerating after increase in water status than on plants that had received abundant water continuously. They fed mainly on the old wood and very little on the soft regenerative shoots, so were apparently favoured by some change in the peripheral tissues of the main stem.

On HW plants, nearly all feeding took place on woody or partially hardened tissue; newly flushing tissue was not fed on if it was growing normally. On IW plants, the expansion of new terminal leaves was often slow, and these tissues were then attacked by young larvae. This happened much more on LW plants, where the apical region was killed by persistent feeding. On all plants larvae older than second instar fed only on hard tissues.

Later effects of feeding were splitting of the wood where lesions had been made and sometimes the development of fungal infecdtions. The most severe infections occurred when the upper part of the old stem died back on LW plants that were regenerating after increase in water status.

Type
Research Paper
Copyright
Copyright © Cambridge University Press 1966

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

Bursell, E. (1964). Environmental aspects: humidity. In Rockstein, M.Ed. The physiology of Insecta. Vol. I pp. 323361. New York & London, Academic Pr.Google Scholar
Carter, W. (1962). Insects in relation to plant disease.—705 pp. New York & London, Interscience Publishers.Google Scholar
Cotterell, G. S. (1928). Minor pests of cacao.—Bull. Dep. Agric. Gold Cst no. 13 pp. 100106.Google Scholar
Cotterell, G. S. (1943). Sahlbergella and related capsids.—Rep. cent. Cocoa Res. Sta., Tafo, 1938–42 pp. 4651.Google Scholar
Crowdy, S. H. (1947). Observations on the pathogenicity of Calonectria rigidiuscula (Berk. & Br.) Sacc. on Theobroma cacao L.—Ann. appl. Biol. 34 pp. 4559.CrossRefGoogle ScholarPubMed
Fennah, R. G. (1955). The epidemiology of cacao-thrips on cacao in Trinidad.—Rep. Cacao Res. 1954 pp. 726.Google Scholar
Fennah, R. G. (1959). Nutritional factors associated with the development of mealybugs on cacao.—Rep. Cacao Res. 1957–58 pp. 1828.Google Scholar
Fennah, R. G. (1963). Nutritional factors associated with seasonal population increase of cacao thrips, Selenothrips rubrocinctus (Giard) (Thysanoptera), on cashew, Anacardium occidentale.—Bull. ent. Res. 53 pp. 681713.CrossRefGoogle Scholar
Fennah, R. G. (1965). The influence of environmental stress on the cacao tree in predetermining the feeding sites of cacao thrips, Selenothrips rubrocinctus (Giard), on leaves and pods.—Bull. ent. Res. 56 pp. 333349.CrossRefGoogle Scholar
Goodchild, A. J. P. (1952). A study of the digestive system of the West African cacao capsid bugs (Hemiptera, Miridae).—Proc. zool. Soc. Lond. 122 pp. 543572.Google Scholar
Taylor, D. J. (1955). Capsid studies: population studies.—Rep. W. Afr. Cocoa. Res. Inst. 1954–55. pp. 6163.Google Scholar
Taylor, D. J. (1957). Capsid studies: light trapping.—Rep. W. Afr. Cocoa. Res. Inst. 1955–56 pp. 5455.Google Scholar
Williams, G. (1953). Field observations on the cacao mirids, Sahlbergella singularis Hagl. and Distantiella theobroma (Dist.), in the Gold Coast. Part I. Mirid damage.—Bull. ent. Res. 44 pp. 101119.CrossRefGoogle Scholar
Williams, G. (1954). Field observations on the cacao mirids, Sahlbergella singularis Hagl. and Distantiella theobroma (Dist.), in the Gold Coast Part III. Population fluctuations.—Bull. ent. Res. 45 pp. 723744.CrossRefGoogle Scholar