Development of Trichogramma australicum Girault in eggs of Helicoverpa armigera and in artificial diet
Dahlan, A.N.; Gordh, G.
Australian Journal of Entomology 37(3): 254-264
ISSN/ISBN: 1326-6756 DOI: 10.1111/j.1440-6055.1998.tb01580.x
Development of Trichogramma australicum in eggs of Helicoverpa armigera and in artificial diet was compared. Females required significantly more time to insert their ovipositors into artificial eggs than into host eggs. The number of eggs deposited by a female wasp in artificial diet was significantly higher than in H. armigera eggs. Duration of egg, larval and prepupal stages was longer in artificial diet than in host eggs, but the pupal stage was shorter in artificial diet. Immatures and adults of T. australicum reared in artificial diet were significantly larger than those reared in host eggs. Compared with controls, mortality of immature T. australicum was not significantly different in host eggs, but was significantly different in artificial diet. A higher number of abnormal wasps emerged from artificial diet, whereas no abnormal wasps emerged from host eggs. Differences in the amount of diet or ooplasm consumption, varying chemical constituents and physical properties of artificial diet and host eggs may have contributed to the observed differences in development of T. australicum.