The objective of this research was to evaluate the performance of Trichogramma pretiosum Riley and Trichogramma exiguum Pinto & Planter on different densities of Plutella xylostella eggs (L.). For both species, groups were made with one, two and four females of Trichogramma, and each group was confined in glass tubes with 15, 30, 45 and 60 eggs of P. xylostella for 24 hours. Cycle duration (adult egg) of T. pretiosum and T. exiguum was around nine days. The highest parasitism rate of T. pretiosum and T. exiguum were reached when it used 15 eggs four females-1 and 15 eggs two females-1, respectively. The viability of parasitism for T. pretiosum and T. exiguum was not affected by the combinations of parasitoids and eggs for both species. The sex ratio was one for T. pretiosum and it varied from 0.6 to 0.8 to T. exiguum. The number of emerged individuals per egg was one. The greatest deformation rate of descendants for both species were observed in tubes containing four female 15 eggs-1 with 33.9 for T. pretiosum and 17.5 for T. exiguum, respectively. The most indicated combination for T. pretiosum and T. exiguum, was one female for 15 eggs-1 and two famales 15 eggs-1, respectively.
diamondback moth; biological control; eggs parasitoid; parasitism rate
