Trichogramma fuentesi Torre was identified attacking Cactoblastis cactorum (Berg), a serious pest of Opuntia spp. in North America, raising the possibility of using this egg parasitoid as an inundative biological control agent. Studies were conducted to assess the biological parameters of this parasitoid under laboratory conditions. Nutritive quality influence of the rearing supplement on the parasitoid's longevity, mating, and age was evaluated based on the level of parasitism. The presence and type of food source had a positive impact on female longevity, and female parasitoids given a diet composed of pure honey lived the longest; an average of 11 d. Mated females parasitized a greater number of C. cactorum host eggs than did unmated females. Percent parasitism significantly decreased with female age. Two- to 3-day old female parasitoids had the highest level of parasitism. Two-day old host eggs were the optimal host egg age for parasitization by T. fuentesi. In the context of implementing an inundative biological control program against C. cactorum, two-day old mated and honey fed Trichogramma females should be released to increase level of control.