Skip to main content Accessibility help
×
Home

Defoliation and consequent crop loss in cassava caused by the grasshopper Zonocerus variegatus (L.) (Orthoptera: Pyrgomorphidae) in southern Nigeria

  • W. W. Page (a1), J. R. W. Harris (a1) and A. Youdeowei (a2)

Abstract

Severe defoliation of cassava by Zonocerus variegatus (L.) can occur every year during the dry season in southern Nigeria, but the effect of such defoliation on tuber yield was not known. Experiments simulating different forms of damage and direct observation on damage by Z. variegatus indicated that tuber yield is reduced significantly by defoliation only towards the end of the dry season after natural leaf regeneration has begun, when its effect is to delay regeneration so that damaged plants lag behind those which are undamaged. Continuous defoliation over six weeks at the end of the dry season caused a mean crop loss of 63%, and simulated debarking a mean loss of 49%. Z. variegatus confined in plots until the end of the dry season caused a mean loss of 36%, losses being less than those caused by simulated defoliation because cropping took place sooner after the end of defoliation. Defoliation during the dry season caused no significant crop loss when damage occurred before leaf regeneration at the beginning of the following wet season. Monitoring of natural defoliation by Zonocerus in successive years showed there were considerable differences in amount and timing. It is concluded that crop loss due to Zonocerus damage is significant only occasionally despite defoliation occuring every year.

Copyright

References

Hide All
Bernays, E. A., Chapman, R. F., Leather, E. M., McCaffery, A. R.. & Modder, W. W. D.. (1977). The relationship of Zonocerus variegatus (L.) (Acridoidea: Pyrgomorphidae) with cassava (Manihot esculenta).—Bull. ent. Res. 67, 391404.
Copr, (1974). Control of Zonocerus variegatus (L.) in Nigeria: interim report, January 1972-July 1973.—17 pp. London, Centre for Overseas Pest Research.
Cours, G. (1951). Le manioc à Madagascar.—Mém. Inst. scient. Madagascar (B) 3, 203400.
Doku, E. V. (1965). Breeding for yield in cassava. I. Indices of yield.—Ghana J. Sci. 5, 4259.
Doku, E. V. (1969). Cassava in Ghana.—44 pp. Accra, Ghana Universities Press.
Golding, F. D. (1948). The Acrididae (Orthoptera) of Nigeria.—Trans. R. ent. Soc. Lond. 99, 517587.
Hunt, L. A., Wholey, D. W.. & Cock, J. H.. (1977). Growth physiology of cassava (Manihot esculenta Crant).—Fld Crop Abstr. 30, 7791.
Rvine, F. R. (1969). West African crops.—272 pp. Oxford, Oxford University Press.
Ones, W. (1959). Manioc in Africa.—315 pp. California, Stanford University Press.
Massey, H. S. W.. & Kestelman, H.. (1959). Ancillary mathematics.—990 pp. London, Pitman & Sons.
Phipps, J. (1970). Notes on the biology of grasshoppers (Orthoptera: Acridoidea) in Sierra Leone.—J. Zool. 161, 317349.
Toye, S. A. (1974). Feeding and locomotory activities of Zonocerus variegatus (L.) (Orthoptera, Acridoidea).—Revue zool. afr. 88, 205212.
Vuillaume, M. (1953). Chimiotropisme, préférences alimentaires de Zonocerus variegatus L. (Acrid., Pyrgomorphinae).—Revue Path. vég. Ent. agric. Fr. 32, 161170.

Defoliation and consequent crop loss in cassava caused by the grasshopper Zonocerus variegatus (L.) (Orthoptera: Pyrgomorphidae) in southern Nigeria

  • W. W. Page (a1), J. R. W. Harris (a1) and A. Youdeowei (a2)

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed