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Persistent populations of males of the African armyworm, Spodoptera exempta (Walker) (Lepidoptera: Noctuidae), in Malawi

Published online by Cambridge University Press:  10 July 2009

G. K. C. Nyirenda
Affiliation:
Makoka Research Station, Private Bag 3, Thondwe, Malawi

Abstract

Regular catches of males of Spodoptera exempta (Walker) were made in 41 pheromone disc traps scattered throughout Malawi in 1978–82. Each trap had a vial, replaced monthly, containing 2 mg of a 13·3:1 mixture of two sex-pheromone components of the female. Over the five-year period, males were caught every month at a majority of sites throughout the country, suggesting that they came from populations resident in Malawi. Sites at which moths were regularly caught had areas with green grass throughout the year which could have sustained larvae within their vicinity. A few sites at which moths were caught only occasionally had very dry immediate surroundings in the dry season, and it is suggested that moths caught at these sites are primarily migrants from either within or outside Malawi. There was no obvious relationship between site elevation, monthly rainfall and monthly moth catches or whether moths were caught persistently or irregularly. The results strongly suggest that some of the moths captured throughout the year in Malawi developed locally while some originate in other countries such as Mozambique.

Type
Original Articles
Copyright
Copyright © Cambridge University Press 1985

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References

Beevor, P. S., Hall, D. R., Lester, R., Poppi, R. G., Read, J. S. & Nesbitt, B. F. (1975). Sex pheromones of the armyworm moth, Spodoptera exempta (Wlk.).—Experientia 31, 2223.CrossRefGoogle ScholarPubMed
Blair, B. W., Rose, D. J. W. & Law, A. B. (1980). Synoptic weather associated with outbreaks of African armyworm, Spodoptera exempta (Wlk.) (Lepidoptera, Noctuidae), in Zimbabwe during 1973 and 1976/77.—Zimbabwe J. agric. Res. 18, 95110.Google Scholar
Brown, E. S., Betts, E. & Rainey, R. C. (1969). Seasonal changes in distribution of the African armyworm, Spodoptera exempta (Wlk.) (Lep., Noctuidae), with special reference to Eastern Africa.—Bull. ent. Res. 58, 661728.CrossRefGoogle Scholar
Faure, J. C. (1943). Phase variation in the armyworm Laphygma exempta (Wlk.).—Sci. Bull. Dep. Agric. For. Un. S. Afr. no. 234, 17 pp.Google Scholar
Hattingh, C. C. (1941). The biology and ecology of the armyworm (Laphygma exempta) and its control in South Africa.—Sci. Bull. Dep. Agric. For. Un. S. Afr. no. 217, 50 pp.Google Scholar
Khasimuddin, S. (1977). The occurrence of an aestivating/diapausing phenomenon in the African armyworm, Spodoptera exempta (Wlk.), (Lepidoptera: Noctuidae).—E. Afr. agric. For. J. 42, 350.CrossRefGoogle Scholar
Marks, R. J. (1976). Field evaluation of gossyplure, the synthetic sex pheromone of Pectinophora gossypiella (Saund.) (Lepidoptera. Gelechiidae) in Malawi.—Bull. ent. Res. 66, 267278.CrossRefGoogle Scholar
Pedgley, D. E. & Rose, D. J. W. (1982). Conference report: International Workshop on the Control of Armyworm and Other Migrant Pests in East Africa, Arusha, July 1982.—Tropical Pest Management 28, 437440.CrossRefGoogle Scholar
Rose, D. J. W. (1979). The significance of low-density populations of the African armyworm Spodoptera exempta (Wlk.).—Phil. Trans. R. Soc. (B) 287, 393402.Google Scholar
Rose, D. J. W. & Law, A. B. (1976). The synoptic weather in relation to an outbreak of the African armyworm, Spodoptera exempta (Wlk.).—J. ent. Soc. sth. Afr. 39, 125130.Google Scholar
Tucker, M. R. & Pedgley, D. E. (1983). Rainfall and outbreaks of the African armyworm, Spodoptera exempta (Wlk.) (Lepidoptera: Noctuidae).—Bull. ent. Res. 73, 195199.CrossRefGoogle Scholar
Whellan, J. A. (1954). The African armyworm and its control.—Rhodesia agric. J. 51, 415427.Google Scholar