Fecundity, development period, percent emergence, longevity, sex ratio and hind tibia lenght of Trichogramma brassicae Bezd. (Hym.: Trichogrammatidae) were evaluated in five consecutive rearing generations on the eggs of Sitotroga cerealella Oliv. (Lep.: Gelechiidae) & Plodia interpunctella Hub. (Lep.: Pyralidae) in 24±1?C, 60±5% RH and 14:10(L:D). The means figures for the mentioned characters (for wasps reared on the eggs of S. cerealella and P. interpunctella) were obtained as fallows: fecundity: 34.55 and 21.65 eggs per female, development period: 11.60 and 11.41 days, percent of emergence: 93.52 and 77.01, longevity: 3.04 and 2.44 days, the sex ratio: 64.55 and 60.01 and the hind tibia lenght: 158.08 and 146.45 microns. The means of fecoundity, longevity, sex ratio and hind tibia lenght of wasps reared on either host indicated significant differences, increasing until 3rd generation then decreasing in the next generations, while the means for development period and percent of emergence exhibited no significant difference in any five rearing generations. Also strong positive correlations among the hind tibia length, fecundity, and longevity of the wasps reared on either host were observed. According to the obtained results non continual rearing of this wasp on one host is suggested in its mass production.
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