Some Experiments in Rearing Trichogramma australicum Girault.
Paitoon Leksawasdi* and Sutham Areekul.**(1975)
* Biology Department Faculty of Science Chiang Mai University.
**Department of Entomology and Plant Pathology, Kasetsart University.
Trichogramma australicum Girault fed effectively on eggs of Corcyra cephalonica (Stainton) but not on Sitotroga cerealella (Oliver) and Callosobruchus maculatus (Fabricius). The rate of production of Corcyra cephalonica was 91.45-102.8 eggs per female on the average when reared on broken milled rice in plastic boxes. Egg laying of this insect was highest in the first day and lasted on the seventh day. The rate of egg production was unaffected by population density of the moth in this experiment.
The maximum rate of parasitism per female on Corcyra cephalonica was 35.90 eggs at the age of 1.5 days old. It was reduced by the increasing age of the host and the parasite fed unsuccessfully when the host attained 4.5 days of age. The survival rate of the parasite in host eggs was not affected by temperatures ranging from 20º-34º C. The life duration was prolonged by low temperature and it ranged 16-18 days at 20º C. It was extended to 36 days with the survival rate exceeded 70% when the parasites at the pupal stage were kept in eggs of host at 10º-11ºC and 95% RH. No significant effect on the survival rate of immature stage of the parasite was observed when reared in eggs of the host under the relative humidity ranging from 32-95% and the temperature at 28ºC. The oviposition rates of the parasite on eggs of the host were high either in the total darkness or under the strong light condition. The adult parasite was attracted most by light with the intensity not less than 30 ft, candles.
