Feeding of the adult parasite of Trichogramma evanescens Westwood on a honey solution containing 500 μg of Bacillus thuringiensis var. galleriae HD-129 for 4–5 days had no effect on their longevity, productivity or their capability to parasitize the host eggs of Spodoptera littoralis (Boisdüvalle) or Anagasta kuehniella Zeller. After spraying the freshly laid host eggs with B. thuringiensis at the same concentration, a significant decrease was observed in the percentage of parasitism. No deleterious effects were observed in the development of the immature stages of the parasite and the percentage of its emergence, as affected by B. thuringiensis, when applied to the host eggs before or after parasitism.