, Volume 26, Issue 4, pp 445–451 | Cite as

Effect of hosts and parasite density on the egg parasiteTrichogramma pretiosum [Hym.: Trichogrammatidae]

  • Rami Kfir


When females ofTrichogramma pretiosumRiley were confined with host eggs at a density of 2/150 eggs, they produced 12 times more female progeny on eggs of potato tuber moth than on eggs ofHeliothis armigera (Hübner) and 13,6 times more on eggs ofSitotroga cerealella (Olivier) than on eggs ofHeliothis. At a density of 4/150 eggs, the correspondent figures were 13 and 8 times. The percentage emergence fromHeliothis eggs was from 0,29 to 0,14 times as great as from tuber moth orSitotroga. From 15 to 140 times more runts were observed amongTrichogramma fromHeliothis eggs than among those from tuber moth eggs and 8 times more thant among those fromSitotroga eggs. This may explain the low recoveries in South Africa ofT. pretiosum in eggs ofH. armigera collected in cotton fields after mass liberation of the parasite. An increase in parasite density from 1/300 eggs to 16/300 eggs resulted in a decrease from 29 to 14 in the hosts parasitised per female, a decrease in the proportion of female progeny from 72 to 39%, a decrease in the female progeny per female from 18 to 4,8, and an increase in the proportion of runts from 2,4 to 12,4%. It is suggested that in mass culture ofTrichogramma unduly high parasite densities should be avoided in order to reduce the effect of mutual interference and raise the output of female progeny.


Plant Pathology Potato Tuber Parasite Density Mass Culture Parmi 
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Des femelles deTrichogramma pretiosumRiley mises en présence avec les œufs hôtes à une densité de 2/150 œufs, produisirent 12 fois plus de progéniture femelle sur les œufs dePhthorimea operculellaZeller que sur les œufs d'Heliothis armigera (Hübner) et 13,6 fois plus sur les œufs deSitotroga cerealella (Olivier), que sur les œufs d'Heliothis. A une densité de 4/150 œufs, les chiffres, correspondants furent de 13 et 8 fois. Le pourcentage d'émergence des œufs d'Heliothis fut de 0,29 à 0,14 fois aussi élevé que ceux de la teigne de la pomme de terre ou deSitotroga. De 15 à 140 fois plus d'individus nains furent observés chez lesTrichogramma issus des œufs d'Heliothis que chez ceux provenant de la teigne de la pomme de terre et 8 fois plus que parmi ceux élevés sur œufs deSitotroga. Ceci peut expliquer les faibles reprises en Afrique du Sud deT. pretiosum dans les œufs d'H. armigera ramassés dans les champs de coton après une libération massive du parasite. Une augmentation dans la densité des parasites de 1/300 œufs à 16/300 œufs a entrîné une diminution de 29 à 14 chez les hôtes parasités par femelle, une diminution dans la proportion de la progéniture femelle de 72 à 39%, une diminution dans la proportion de la progéniture femelle par femelle de 18 à 4,8, et une augmentation dans la proportion des nains de 2,4 à 12,4%. Il est suggéré que pour l'élevage de masse deTrichogramma des densités exagérément élevées de parasites devraient être évitées, afin de réduire l'effet d'interférence mutuelle et d'accroître la production de progéniture femelle.


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  1. Evans, H. F. — 1976. Mutual interference between predatory anthocorids. —Ecol. Entomol., 1, 283–286.Google Scholar
  2. Flanders, S. E. — 1930. Mass production of egg parasites of the genusTrichogramma. —Hilgardia, 4, 465–501.Google Scholar
  3. — — 1935. Host influence on the prolificacy and size ofTrichogramma. —Pan Pac. Entomol., 11, 175–177.Google Scholar
  4. — — 1945. Mass production ofTrichogramma using eggs of potato tuber worm. —J. Econ. Entomol., 38, 394–395.Google Scholar
  5. Kfir, R. & Rosen, D. — 1981. Biological studies ofMicroterys flavus (Howard) [Hymenoptera: Encyrtidae], a primary parasite of soft scale. —J. Entomol. Soc. Sth. Afr., 43.Google Scholar
  6. Kfir, R., Podoler, H. &Rosen, D. — 1976. The area of discovery and searching strategy of a primary parasite and two hyperparasites. —Ecol. Entomol., 1, 287–295.Google Scholar
  7. Klomp, H. &Teerink, B. J. — 1962. Host selection and number of eggs per oviposition in the egg parasiteTrichogramma embryophagum Htg.Nature, 195, 1020–1021.Google Scholar
  8. — — 1967. The significance of oviposition rates in the egg parasiteTrichogramma embryophagum Htg.Arch. Néerl. Zool., 17, 350–375.Google Scholar
  9. Lewis, W. J., Nordlund, D. A., Gross, H. R., Jr., Perkins, W. D., Knipling, E. F. &Voegelé, J. — 1976. Production and performance ofTrichogramma reared on eggs ofHeliothis zea and other hosts. —Environ. Entomol., 5, 449–452.Google Scholar
  10. Marston, N. &Eartle, L. R. — 1973. Host influence on the bionomics ofTrichogramma minutum. —Ann Entomol. Soc. Am., 66, 1155–1162.Google Scholar
  11. Parker, F. D. &Pinnell, R. E. — 1974. Effectiveness ofTrichogramma spp. in parasitizing eggs ofPieris rapae andTrichoplusia ni in the laboratory. —Environ. Entomol., 3, 935–938.Google Scholar
  12. Parry Jones, E. — 1937. The egg parasites of the cotton boll worm,Heliothis armigera,Hübn. (obsoleta,Fabr.), in southern Rhodesia. —Mazoe Citrus Experimental Station, 6, 35–105.Google Scholar
  13. Salt, G., — 1940. Experimental studies in insect parasitism.Vii. The effect of different hosts on the parasiteTrichogramma evanescens Westw [Hym. Chalcidoidea]. —Proc. R. Entomol. Soc. Lond. (A)., 15, 81–95.Google Scholar
  14. Stinner, R. E. — 1977. Efficacy of inundative releases. —Annu. Rev. Entomol., 22, 515–531.CrossRefGoogle Scholar
  15. Stinner, R. E., Ridgway, R. L., Coppedge, J. R., Morrison, R. K. &Dikerson, W. A. Jr. — 1974a. Parasitism ofHeliothis eggs after field releases ofTrichogramma pretiosum in cotton. —Environ. Entomol., 3, 497–500.Google Scholar
  16. Stinner, R. E., Ridgway, R. L. &Morrison, R. K. — 1974b. Longevity, fecundity, and searching ability ofTrichogramma pretiosum reared by three methods. —Environ. Entomol. 3, 558–560.Google Scholar
  17. Varley, C. G., Gradwell, G. R. & Hassell, M. P. — 1973. Insect Population Ecology. An analytical approach. — Blackwell Sci. Publ., 212 pp.Google Scholar
  18. Viktorov, G. A. — 1968. The influence of the population density upon the sex ratio inTrissolcus grandis Thoms. [Hymenoptera, Scelionidae]. —Zool. Zh., 47, 1035–1039.Google Scholar
  19. Wylie, H. G. — 1965. Some factors that reduce the reproductive rate ofNasonia vitripennis (Walk.) at high adult population densities. —Can. Entomol., 97, 970–977.Google Scholar

Copyright information

© Balthazar Publications 1981

Authors and Affiliations

  • Rami Kfir
    • 1
  1. 1.Plant Protection Research InstitutePretoriaSouth Africa

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