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Epizootiological observations on a nuclear polyhedrosis of the African armyworm Spodoptera exempta (Walk.)

Published online by Cambridge University Press:  19 September 2011

M. O. Odindo
M. O. Odindo
Affiliation:
Department of Entomology, University of Nairobi, P.O. Box 30197, Nairobi, Kenya
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Abstract

Field observations were carried out on a natural outbreak of a nuclear polyhedrosis virus of the armyworm Spodoptera exempta. Records were kept in four study sites with varying larval density, vegetation cover, and climatic conditions. Biotic factors influencing disease outbreaks were also noted. Initial mortality was recorded 11 days after larval outbreak, and the highest mortality occurred 10 days later. The epizootic was highest in sites of high larval density, wide fluctuations of daily temperatures (range 16.2°C), and high relative humidity. Rainfall was recorded in all disease outbreak sites. An acridid Acrotylus patruelis fed on larval cadavers in the field. Polyhedral inclusion bodies recovered from the gut of A. patruelis caused disease when fed to third instar S. exempta larvae in the laboratory. Predation on larvae by the pied crow Corvus albus in some observation sites reduced larval numbers, and may have prevented NPV from rising to epizootic levels in such areas. In sites of high polyhedrosis incidence, the disease led to larval population collapse in 3 weeks following disease outbreak.

Keywords

Spodoptera exemptanuclear polyhedrosis virusepizooticAcrotylus patruelislarval densitytemperature fluctuationsrainfallCorvus albuspredator
Type
Research Article
Information
International Journal of Tropical Insect Science , Volume 4 , Issue 3 , September 1983 , pp. 291 - 298
Copyright
Copyright © ICIPE 1983

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References

REFERENCES

Ayuzawa, C. and Sato, T. (1961) On the induction of polyhedrosis in the silkworm Bombyx mori L. by the exposure to low temperature with different relative humidities. Jaust-Kenkyu 37, 96–99.Google Scholar
Bergoin, M. (1966) Passage des corps d'inclusion de virus d'une polyedrie nucléaire dans le tube digestif d'un orthoptère d'etriti vore, Acheta domesticus L. Entomophaga 11, 253–259.CrossRefGoogle Scholar
Bird, F. T. and Elgee, D. E. (1957) A virus disease and introduced parasites as factors controlling European spruce sawfly Diptrion hercyniae Htg. in central New Brunswick. Can. Ent. 89, 37–78.CrossRefGoogle Scholar
Brown, E. S. (1966) New evidence on the migration of moths of the African armyworm Spodoptera exempta (Walk.) (Lep., Noctuidae). Bull. ent. Res. 56, 67–84.CrossRefGoogle Scholar
Brown, E. S. (1970) Control of the African armyworm Spodoptera exempta (Walk.), an appreciation of the problem. E. Afric. Agric. For. J. 35, 237–245.CrossRefGoogle Scholar
Brown, E. S. and Swaine, G. (1965) Virus disease of the African armyworm Spodoptera exempta (Walk.). Bull. ent. Res. 56, 95–116.CrossRefGoogle Scholar
David, W. A. L. (1967) In Insect Pathology and Microbrial Control (Ed. by P. A., Van der Laan), pp. 174–178. North-Holland Publ. Co., Amsterdam.Google Scholar
Entwistle, P. F., Adams, P. H. W. and Evans, H. F. (1977a) Epizootiology of a nuclear polyhedrosis virus in European spruce sawfly Gilpinia hercyniae: the status of birds as dispersal agents during the larval period. J. Invertebr. Pathol. 29, 354–360.CrossRefGoogle Scholar
Entwistle, P. F., Adams, P. H. W. and Evans, H. F. (1977b) Epizootiology of a nuclear polyhedrosis virus in European spruce sawfly Gilpinia hercyniae: birds as dispersal agents of the virus during winter. J. Invertebr. Pathol. 30, 15–19.CrossRefGoogle Scholar
Entwistle, P. F., Adams, P. H. W. and Evans, H. F. (1978) Epizootiology of a nuclear polyhedrosis virus in European spruce sawfly Gilpinia hercyniae: the rate of passage of infective virus through the gut of birds during cage tests. J. Invertebr. Pathol. 31, 307–312.CrossRefGoogle ScholarPubMed
Graham, J. F. (1961) Outbreaks of the armyworm. In Outbreaks and New Records, Vol. 9, pp. 181–184. FAO Plant Prot. Bull. 9, 181–184.Google Scholar
Jack, R. W. (1930) The armyworm. Rhodesia agric J. 27, 912–924.Google Scholar
Jaques, R. P. (1962) Stress and nuclear polyhedrosis in a crowded population of Trichoplusia ni (Hubner) J. Insect. Pathol. 4, 1–22.Google Scholar
Jaques, R. P. (1972) The inactivation of foliar deposits of viruses of Trichoplusia ni (Lepidoptera, Noctuidae) and Pieris rapae (Lepidoptera, Pieridae) and tests on protectant additives. Can Ent. 104, 1985–1994.CrossRefGoogle Scholar
Magnoler, A. (1968) A field test for the control of Lymantria dispar with nuclear polyhydrosis virus. Ann. Sac. Ent. Fr. (N.S.) 4, 227–232.Google Scholar
Odindo, M. O. (1977) Comparative studies on the histopathology and symptomatology of a nuclear polyhydrosis of Spodoptera exempta (Walk.) (Noctuidae, Lepidoptera). E. Afr. Agric For. J. 42, 287–295.CrossRefGoogle Scholar
Odindo, M. O. (1981a) Dosage–mortality and time–mortality responses of the armyworm Spodoptera exempta (Walk.) to a nuclear polyhedrosis virus J. Invertebr. Pathol. 38, 251–255.CrossRefGoogle Scholar
Odindo, M. O. (1981b) Time—mortality response in Spodoptera exempta (Walk.) infected with heat-treated nuclear polyhydrosis virus. Insect Sci. Application 1, 225–230.Google Scholar
Stairs, G. R. (1968) Numerical ecology of inclusion type of insect viruses. Proc. N. cent. Brch. Am. Ass. econ. Ent. 23, 39–45.Google Scholar
Smirnoff, W. A. (1967) Influence of temperature on the development of a virus disease of Neodiprion swainei (Hymenoptera, Tenthredinidae). Can. Ent. 99, 244–249.CrossRefGoogle Scholar
Swaine, F. (1966) Generation to generation passage of the nuclear polyhedral virus of Spodoptera exempta (Walk.). Nature, Lond. 210, 1053–1054.CrossRefGoogle Scholar
Tanada, Y. (1961) The epizootiology of virus diseases in field populations of the armyworm Pseudaletia unipuncta (Haworth). J. Insect Path. 3, 310–323.Google Scholar
Vago, C., Fosset, J. and Bergoin, M. (1966) Dissemination des virus de polyedries par les ephippigères prédateurs d'insectes. Entomophaga 11, 177–182.CrossRefGoogle Scholar
Wallis, R. C. (1957) Incidence of polyhedrosis of gypsymoth larvae and the influence of relative humidity. J. econ. Ent. 50, 580–583.CrossRefGoogle Scholar