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Key factor responsible for fluctuations in rice yellow stemborer populations in deepwater rice ecosystems

Published online by Cambridge University Press:  19 September 2011

Zahirul Islam
Zahirul Islam
Affiliation:
Entomology Division, Bangladesh Rice Research Institute, Gazipur 1701, Bangladesh
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Abstract

A series of life tables (22 generations) for the rice yellow stem borer, Scirpophaga incertulas (Walker), a major pest of rice in Bangladesh, was constructed. In a deepwater rice ecosystem, the S. incertulas population dropped to a low level in the second or third generation (May-June), then reached the annual peak level in the fifth generation during September-October. The population dropped again to the lowest level in the sixth generation (November-February) when the larvae remained in diapause for about 3 months. In general, the population suffered very high mortality (99%). The estimated egg mortality was 49%; about 96% of the hatched larvae failed to penetrate into the rice stem; 39% larvae and 27% pupae died inside the stem. The population suffered very high mortality (96 %) at the early larval stage and the resultant survivorship curve was type III. Key factor analysis revealed that the disappearance of newly hatched larvae before penetration into the rice stem was the key mortality factor responsible for population fluctuations between generations. Disappearance of young larvae and egg mortality were density-dependent, but of a weak type.

Résumé

Une série de budgets vitaux (portant sur 22 générations) ont été construits pour le foreur de la tige de riz, Scirpophaga incertulas (Walker), un important ravageur du riz au Bangladesh. Dans un écosystéme de riz flottant, la population de S. incertulas a chuté à un bas niveau à la 2éme et 3éme génération (Mai-Juin), puis a atteint son pic annuel à la 5éme génération (September-Octobre) pour ensuite génération (Novembre-Fevrier), au moment où les larves entraient en diapause durant 3 mois environ. En général, la population a subi une trés forte mortality (99%). La mortalité au niveau des oeufs était estimee à 49%; environ 96% de larves écloses n'ont pas réussi à pénétrer dans la tige du riz; 39% de larves et 27% de pupes étaient mortes a I'interieur de la tige. La population a subi une trés forte mortalité à un stade larvaire précorce et la courbe de survie qui en a résulté était du type III. L'analyse du facteurolé a révélé que la disparition de larves nouvellement écloses avant leur penetration dans la tige, était principalement responsable des fluctuations des populations observées entre les générations. La disparition de jeunes larves et la mortalite au niveau des oeufs étaient dépendantes de la densité, mais leur cocours était faible.

Keywords

deepwater ricedensity-dependentkey factorlife tableScirpophaga incertulasyellow stemborerriz flottanteffet de la densitéfacteurolébudget vitalScirpophaga incertulasforeur de la tige
Type
Research Articles
Information
International Journal of Tropical Insect Science , Volume 15 , Issue 4-5 , October 1994 , pp. 461 - 468
Copyright
Copyright © ICIPE 1994

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References

REFERENCES

Banerjee, S. N. and Pramanik, L. M. (1967) The lepidopterous stalk borers of rice and their life cycle in the tropics. In The Major Insect Pests of the Rice Plant. John Hopkins Press, Baltimore, USA, pp. 103–124.Google Scholar
Catling, H. D., Islam, Z. and Alam, B. (1983) Egg parasitism of the yellow rice borer, Scirpophaga incertulas (Lep.: Pyralidae), in Bangladesh. Entomophaga 28, 227–239.CrossRefGoogle Scholar
Catling, H. D., Islam, Z. and Pattrasudhi, R. (1984) Seasonal occurrence of the yellow stem borer, Scirpophaga incertulas (Walker), on deepwater rice in Bangladesh and Thailand. Agric, Ecosystem Environ. 12, 47–71.Google Scholar
Catling, H. D., Islam, Z. and Pattrasudhi, R. (1987) Assessing yield losses in deepwater rice due to yellow stem borer, Scirpophaga incertulas (Walker), in Bangladesh and Thailand. Crop Prot. 6, 20–27.Google Scholar
Gu, D., Yin, J. and Pang, X. (1984) Study on the population dynamics of the paddy borer, Scirpophaga incertulas (Walker) in Shixing county and its control strategies. Gaung Dong Agric. Sci. 3, 31–33 (in Chinese English abstract).Google Scholar
Hassell, M. P. (1976) The Dynamics of Competition and Predation. Edward Arnold, London.Google Scholar
Islam, Z. (1990) Influence of Scirpophaga incertulas (Lepidoptera: Pyralidae) on deepwater rice. Bull. Entomol. Res. 80, 301–308.Google Scholar
Islam, Z. (1991) Seasonal history of rice yellow stem borer, Scirpophaga incertulas (Walker) (Pyralidae: Lepidoptera) in Bangladesh. Bangladesh J. Zool. 19(2), 213–221.Google Scholar
Islam, Z. (1992) Mortality of yellow stem borer, Scirpophaga incertulas (Walker), larvae and pupae in deepwater rice stem. Bangladesh J. Zool. 20(2), 367–369.Google Scholar
Islam, Z. and Catling, H. D. (1991) Biology and behaviour of rice yellow stem borer in deepwater rice. J. Plant Prot. Trop. 8, 91–102.Google Scholar
Krebs, C. J. (1978) Ecology: The Experimental Analysis of Distribution and Abundance. Harper and Row, Publishers, New York.Google Scholar
Pathak, M. D. (1968) Ecology of common insect pests of rice. A. R. Entomol. 13, 257–294.CrossRefGoogle Scholar
Rao, C. S., Rao, N. V. and Razvi, S. A. (1983) Parasitism, a key factor in checking rice pest populations. Entomon. 8(1), 97–100.Google Scholar
Rothschild, G. H. L. (1971) The biology and ecology of rice stem borers in Sarawak (Malaysian Borneo). J. Appl. Ecol. 8(2), 287–322.Google Scholar
Southwood, T. R. E. (1978) Ecological Methods: With Particular Reference to the Study of Insect Populations. Chapman and Hall, London.Google Scholar
Suwongwan, P. and Catling, H. D. (1987) Effect of high temperature and low humidity on the survival of eggs and larvae of yellow stem borer, Scirpophaga incertulas (Walker), in deepwater rice. J. Plant Prot. Trop. 4, 115–119.Google Scholar
Varley, G. C., Gradwell, G. R. and Hassell, M. P. (1973) Insect Population Ecology: An Analytical Approach. Blackwell Scientific Publications. Oxford.Google Scholar