Parasitising Efficiency of the Pupal Parasitoid, Tetrastichus howardi (Olliff) (Hymenoptera: Eulophidae) on Chilo partellus (Swinhoe) at Different Exposure Periods

Pupae of Chilo partellus  (Swinhoe) were exposed to one-day-old mated females of Tetrastichus howard (OlIifO) for different periods to determine optimum period of exposure for laboratory production. The percentage parasitism varied significantly from 20 to 80 with different exposure periods. The number of parasitoids obtained per pupa (138.0) and females (71 %) were significantly higher when pupae were exposure for 12 hours and it decreased significantly on increasing exposure period. Though the per cent parasitism was vlry low when the pupae were exposed for 12 hours, the number of parasitoids obtained/ 100 pupae was highest (2760). However, considering progeny production and per cent females obtained, 12 hours exposure period is most suitable for avoiding superparasitism in the lahoratory production of the parasitoid.