DEVELOPMENT OF AN OLIGIDIC DIET FOR IN-VITRO REARING OF TRICHOGRAMMA-GALLOI ZUCCHI AND TRICHOGRAMMA-PRETIOSUM RILEY

The goal of this research was to develop an artificial diet for rearin g Trichogramma galloi and Trichogramma pretiosum, which are important egg parasitoids of several pests in Brazil. The diet was based on diff erent proportions of hemolymph of Helicoverpa tea larvae, chicken egg yolk, powdered milk solutions, bovine fetal serum, and an extract from Heliothis virescens eggs. The ideal volume of diet for rearing IZ: ga lloi was also evaluated. The parasitoids showed different nutritional requirements for their development. The best proportion of diet compon ents for T. galloi was 70% hemolymph, 20% egg yolk, 10% fetal serum, a nd 0.2% streptomycin, and for T. pretiosum it was 70% hemolymph, 20% e gg yolk, 5% fetal serum, 5% egg extract, and 0.2% streptomycin. Egg yo lk was found to be essential for the development of both parasitoids, and the powdered milk solution was not an important component in the d iet. Development was not obtained in diets with hemolymph concentratio ns lower than 40%. A 3- to 4-mu l amount of diet was the ideal volume on which to rear T. galloi with the techniques reported. (C) 1997 Acad emic Press.