Hostname: page-component-78c5997874-v9fdk Total loading time: 0 Render date: 2024-11-14T17:28:58.059Z Has data issue: false hasContentIssue false

A preliminary study on the pathogenicity of two isolates of nucleopolyhedroviruses infecting African bollworm, Helicoverpa armigera (Lepidoptera: Noctuidae)

Published online by Cambridge University Press:  28 February 2007

J.G. Ogembo*
Affiliation:
Laboratory of Biodynamics of Insect–virus Interactions, Graduate School of Bioagricultural Sciences, Nagoya University, 464-8601, Chikusa, Nagoya, Japan
E.C. Kunjeku
Affiliation:
Department of Biological Sciences, University of Zimbabwe, PO Box MP 167, Mt Pleasant, Harare, Zimbabwe:
S. Sithanantham
Affiliation:
International Centre of Insect Physiology and Ecology (ICIPE), PO Box 30 772, Nairobi, 00100, Kenya
Get access

Abstract

Two isolates of nucleopolyhedroviruses (NPVs) from Kenya and South Africa were compared to Gemstar® (a commercial NPV) for their pathogenicity against the first four larval instars of Helicoverpa armigera (Hübner). The larvae were fed on droplets with the three virus products in concentrations of 0 (control), 6×102, 6×103, 6×104 and 6×105 occlusion bodies/μl. The bioassays showed that the median lethal dose (LD50) values of 23 and 631 occlusion bodies for the first and second instars, respectively, were comparable to those of Gemstar®. The LD50 values for the third and fourth instars were 3981 and 39,810 for the Kenyan isolate and 1288 and 25,119 for the South African isolate. There was a linear relationship between the log LD50, the larval age and the lethal time (LT50), which appeared to be dose dependent. This correlation constitutes a useful index for estimating susceptibility of larval populations. The LT50 increased from 2.8 to 11.9 days and 2.8 to 6.8 days, respectively, for the Kenyan and South African isolates, suggesting a slight increase of resistance with age within infected larvae.

Type
Short Communication
Copyright
Copyright © ICIPE 2005

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

Allen, G. E. and Ignoffo, C. M. (1969) The nuclear polyhedrosis virus of Heliothis: Quantitative in vivo estimates of virulence. Journal of Invertebrate Pathology, 13, 378381.CrossRefGoogle Scholar
Baya, J. M. (2000) Survey and evaluation of nuclear polyhedrosis virus (NPV) for the control of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) on selected vegetable crops in Kenya. MSc thesis, Kenyatta University, KenyaGoogle Scholar
Biever, K. D. and Hostetter, D. L. (1971) Activity of the nuclear polyhedrosis virus of the cabbage looper evaluated at programmed temperature regimes. Journal of Invertebrate Pathology, 18, 8184.CrossRefGoogle Scholar
Colvin, J., Cooter, J. R. and Patel, S. (1994) Laboratory mating behaviour and compatibility of Helicoverpa armigera (Lepidoptera: Noctuidae) originating from different geographical regions. Journal of Economic Entomology, 87, 15021506.CrossRefGoogle Scholar
Evans, H. F. (1981) Quantitative assessment of the relationships between dosage and response of the nuclear polyhedrosis virus of Mamestra brassicae. Journal of Invertebrate Pathology, 37, 101109.CrossRefGoogle Scholar
Finney, D. J. (1978) Statistical Method in Biological Assay.Academic Press, New York.Google Scholar
Gettig, R. R. and McCarthy, W. (1982) Genotypic variation among wild isolates of Helicoverpa spp. nuclear polyhedrosis viruses from different geographical regions. Virology, 117, 245252.CrossRefGoogle Scholar
Gould, F., Anderson, A., Jones, A., Sumerford, D., Hechel, D. G., Lopez, J., Micinski, S., Leornard, R. and Laster, M. (1997) Initial frequency alleles for resistance to Bacillus thuringiensis toxin in field population of Heliothis virescens. Proceedings of the National Academy of Sciences, USA, 94, 35193523.CrossRefGoogle ScholarPubMed
Hardwick, D. F. (1965) The corn earworm complex. Memoirs of the Entomological Society of Canada, 40, 1247.Google Scholar
Hughes, P. R. and Wood, H. A. (1981) A synchronous per ora technique for the bioassay of insect viruses. Journal of Insect Pathology, 37, 3134.Google Scholar
Hughes, P. R., van Beek, N. A. M. and Wood, H. A. (1986) A modified droplet-feeding method for rapid assay of Bacillus thuringiensis and baculoviruses in noctuid larvae. Journal of Invertebrate Pathology, 48, 187192.CrossRefGoogle Scholar
Hunter-Fujita, R. F., Entwistle, P. F., Evans, F. H. and Crook, N. E. (1998) Insect Viruses and Pest Management 620 Chichester, UK WileyGoogle Scholar
Kibata, G. N., Mohamed, D. and Sithanantham, S. (2003). Pesticide resistance monitoring and management of Helicoverpa armigera (Hbn.) in eastern and southern Africa: Status and future needs, pp. 7879.. In Integrated Pest and Vector Management (IPVM) in the Tropics: Perspectives and Future Strategies (Abstracts). Proceedings of the 15th Biennial Congress of the African Association of Insect Scientists (AAIS), Nairobi, Kenya, 9–13 June 2003. (Edited by Bahana, J., BalA. B., A. B.,, Dakouo, D. and Omwega, C. O.). ICIPE Science Press, Nairobi.Google Scholar
Moore, S. D., Bouwer, G. and Pittway, T. M. (2004) Evaluation of Helicoverpa armigera nucleopolyhedrovirus (HearNPV) for control of Helicoverpa armigera (Lepidoptera: Noctuidae) on citrus in South Africa. Biocontrol Science and Technology, 14, 239250.CrossRefGoogle Scholar
Ridout, M. S., Fenlon, J. S. and Hughes, P. R. (1993) A generalized One-Hit Model for bioassays of insect viruses. Biometrics, 49, 11361141.CrossRefGoogle Scholar
Rovesti, L., Crook, N. E. and Winstanley, D. (2000) Biological and biochemical relationships between the NPV of Mamestra brassicae and Heliothis armigera. Journal of Invertebrate Pathology, 75, 28.CrossRefGoogle Scholar
Shorey, H. H. and Hale, R. L. (1965) Mass rearing of larvae of nine noctuid species on a simple artificial medium. Journal of Economic Entomology, 58, 522524.CrossRefGoogle Scholar
Smits, P. H. and Vlak, J. M. (1988) Biological activity of Spodoptera exigua nuclear polyhedrosis virus against S. exigua larvae. Journal of Invertebrate Pathology, 51, 107114.CrossRefGoogle Scholar
Teakle, R. E., Jensen, J. M. and Giles, J. G. (1985) Susceptibility of Heliothis armigera to commercial nuclear polyhedrosis virus. Journal of Invertebrate Pathology, 46, 166173.CrossRefGoogle Scholar
Whitlock, V. H. (1977) Effect of larval maturation on mortality induced by nuclear polyhedrosis virus and granulosis virus infections of Heliothis armigera. Journal of Invertebrate Pathology, 30, 8086.CrossRefGoogle Scholar
Zalucki, M. P., Danglish, G., Firempong, S. and Twine, P. (1986) The biology and ecology of Heliothis armigera (Hübner) and H. punctigera Wallengren (Lepidoptera: Noctuidae) in Australia: What do we know?. Australian Journal of Zoology, 34, 779814.CrossRefGoogle Scholar