International Journal of Tropical Insect Science

, Volume 7, Issue 6, pp 701–705 | Cite as

Natural Microsporidian Infection in Laboratory Colonies of Spodoptera spp

  • Ahlam A. Al Fazairy
Research Article


Nosema sp. naturally occurred in both Spodoptera littoralis (Boisd.) and S. exigua (Hübner) laboratory colonies in Alexandria, Egypt (since November 1984). It was responsible for the dramatic suppression of their laboratory populations. Both young (3-day-old) and old (9-day-old) larvae of S. littoralis were susceptible to Nosema sp. However, the pathogen was more effective against the young larvae, especially at high doses, than the old ones. The estimated LC50 was 4.0 × 107 spores/ml, for 3-day-old larvae. The slope value was low (1.2) as typical of protozoan insect pathogens. Heavily infected 9-day-old larvae tended to die as larvae; while less infected ones either pupate or produce larval-pupal intermediate forms (12–23%). The developmental period of both infected larvae and pupae was increased by 4–6 and 3–5 days, respectively. The number of infected insects that reached the adult stage was decreased as the concentration of Nosema sp. spores was increased. Furthermore, infection was shown to reduce adult longevity and fecundity, and viability of the eggs. Larval faecal pellets harboured large numbers of viable spores. Transovum transmission of infection occurred. Two dipterous species, Culex pipiens and Aedes aegypti, were not susceptible to Nosema sp.

Key Words

Nosema sp Spodoptera littoralis Spodoptera exigua Culex pipiens Aedes aegypti susceptibility tests pathogenic effects 


L’infection des colonies laboratoires des deux espéces, Spodoptera littoralis (Boisd.) et Spodoptera exigua (Hübner) par le protozoaire Nosema sp. se produisit naturellement à Alexandrie, en Egypte (depuis Novembre 1984). Ce protozoaire fût responsable de la suppression dramatique de leurs populations au laboratoire. Les jeunes larves de 3 jours, ainsi que celles agées de 9 jours de S. littoralis furent sensibles à l’action pathogène de leur propre Nosema sp. (qui en fût isolé). En tous cas, le pathogène fût beaucoup plus efficace contre les jeunes larves, specialement aux doses elevées, que contre les larves plus agées. La valeur estimée de LC50 pour les larves de 3 jours fût de 4.0 × 107 spores/ml. La valeur de l’inclinaison (Slope) fût basse (1.2), comme typique des protozoaires pathogĕnes d’insectes. Les larves âgées de 9 jours sévèrement infectées, ont tendance a mourir sous forme larvaire, tandis que les moins atteintes ou bien se transforment en pupae, ou bien produisent des formes intermédiaires de larve pupae (12–23%). La période de développement des larves et des pupaes infectées augmenta de 4–6 jours, respectivement. Le nombre des insectes infectés que atteignirent le stage adulte diminua, pendant que la concentration des spores de Nosema sp, augmenta. Aussi, on remarqua que l’infection diminuait la longévité, la fécondité, ainsi que la viabilité des oeufs. Les boulettes de déchets larvaire abritaient de grands nombres de spores, vivantes. La transmission transovarienne de l’infection se présente. Deux espèces de diptères, Culex pipiens et Aedes aegypti ne furent point sensibles au protozoaire Nosema sp.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Al Fazairy A. A. (1983) Microorganisms associated with insect pests of stored products. Ph.D. thesis, Budapest.Google Scholar
  2. Anthony D. W., Lotzkar M. D. and Avery S. W. (1978) Fecundity and longevity of Anopheles albimanus exposed at each larval instar to spores of Nosema algerae. Mosquito News 38, 116–121.Google Scholar
  3. Burges H. D., Canning E. U. and Hurst J. A. (1971) Morphology, development, and pathogenicity of Nosema oryzaephili in Oryzaephitus surinamensis and its host range among granivorous insects. J. invert. Path. 17, 419–432.CrossRefGoogle Scholar
  4. Fisher F. M. and Sanborn R. C. (1964) Nosema as a source of juvenile hormone in parasitized insects. Bioi. Bull. 126, 235–252.CrossRefGoogle Scholar
  5. Gaugler R. R. and Brooks W. M. (1975) Sublethal effects of infection by Nosema heliothidis in the corn earworm, Heliothis zea. J. invert. Path. 26, 57–63.CrossRefGoogle Scholar
  6. Henry J. E. (1981) Natural and applied control of insects by protozoa. Rev. Ent. 26, 49–73.CrossRefGoogle Scholar
  7. Kellen W. R. and Lindegren J. E. (1971) Modes of transmission of Nosema plodiae Kellen and Lindegren, a pathogen of Plodia interpunctella (Hübner). J. stored Prod. Res. 7, 31–34.CrossRefGoogle Scholar
  8. Kellen W. R. and Lindegren J. E. (1974) Comparative virulence of Nosema plodiae and Nosema heterosporum in the Indian meal moth, Plodia interpunctella. J. invert. Path. 23, 242–245.CrossRefGoogle Scholar
  9. Listov M. V. (1977) Microsporidiosis and coccidiosis— protozoan diseases of Tribolium flour beetles Coleoptera, Tenebrionidae. Rev. appl. Ent. 65, 433.Google Scholar
  10. Litchfield J. T. and Wilcoxon F. (1949) A simplified method of evaluating dose-effect experiments. J. Pharmac. exp. Ther. 96, 99–113.Google Scholar
  11. McLaughlin R. E. (1971) Use of protozoans for microbial control of insects. In Microbiol Control of Insects and Mites (Edited by Burges H. D. and Hussey N. W.), pp. 151–172. Academic Press, New York.Google Scholar
  12. Milner R. J. (1972) Nosema whitei, a microsporidian pathogen of some species of Tribolium. III. Effect on T. castaneum J. invert. Path. 19, 248–255.CrossRefGoogle Scholar
  13. Milner R. J. (1972b) Nosema whitei, a microsporidian pathogen of some species of Tribolium. I. Morphology, life cycle, and generation time. J. invert. Path. 19, 231–238.CrossRefGoogle Scholar
  14. Milner R. J. (1973) Nosema whitei, a microsporidian pathogen of some species of Tribolium, IV. The effect of temperature, humidity and larval age on pathogenicity for T castaneoum. Entomophaga 18, 305–315.CrossRefGoogle Scholar
  15. Nordin G. L. and Maddox J. V. (1974) Microsporida of the fall webworm, Hyphantria cunea. I. Identification, distribution, and comparison of Nosema sp. with similar Nosema spp. from other Lepidoptera. J. invert. Path. 24, 1–13.CrossRefGoogle Scholar
  16. Rabindra R. J., Balasubramanian M. and Jayaraj S. (1981) The effects of Farïnocystis tribolii on the growth and development of the flour beetle Tribolium castaneum. J. invert. Path. 38, 345–351.CrossRefGoogle Scholar
  17. Steinhaus E. A. and Marsh G. M. (1962) Report of diagnosis of diseased insects 1951–1961. Hilgardia 33, 349–490.CrossRefGoogle Scholar
  18. Tanabe A. M. and Tamashiro M. (1967) The biology and pathogenicity of a microsporidian (Nosema trichoplusia sp. n.) of the cabbage looper, Trichoplusiae sp. n.) of the cabbage looper, Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae). J. invert. Path, 9, 188–195.CrossRefGoogle Scholar
  19. Thomson H. M. (1958) The effect of a microsporidian parasite on the development, reproduction, and mortality of the spruce budworm, Choristoneura fumiferana (Clem.). Can. J. Zool. 36, 499–511.CrossRefGoogle Scholar
  20. Undeen A. H. and Alger N. E. (1975) The effect of the microsporidian, Nosema algerae on Anopheles stephensi. J. invert. Path. 25, 19–24.CrossRefGoogle Scholar
  21. Veber J. and Jasic J. (1961) Microsporidia as a factor in reducing fecundity in insects. J. Insect Path. 3, 103–111.Google Scholar
  22. Weiser J. (1963) Sporozoan infections. In Insect PathologyAn Advanced Treatise (Edited by Steinhaus E. A.), Vol. 2, pp. 291–334. Academic Press, New York.CrossRefGoogle Scholar
  23. Wilson G. G. (1977) The effects of feeding microsporidian (Nosema fumiferanae) spores to naturally infected spruce budworm (Choristoneura fumiferana). Can. J. Zool. 55, 249–250.CrossRefGoogle Scholar
  24. Windels M. B., Chiang H. C. and Furgala B. (1976) Effects of Nosema pyrausta on pupa and adult stages of the European corn borer, Ostrinia nubilalis. J. invert. Path. 27, 239–242.CrossRefGoogle Scholar
  25. Zimmack H. L. and Brindley T. A. (1957) The effect of the protozoan parasite Perezia pyraustae Paillot on the European corn borer. J. econ. Ent. 50, 637–640.CrossRefGoogle Scholar

Copyright information

© ICIPE 1986

Authors and Affiliations

  • Ahlam A. Al Fazairy
    • 1
  1. 1.Division of Entomology, Department of Plant Protection, Faculty of AgricultureUniversity of AlexandriaAlexandriaEgypt

Personalised recommendations