Inhibition of the spoilage yeastPichia occidentalisin a wheat germ diet for mass rearing ofDrosophila suzukii

Abstract

AbstractA wheat germ diet was initiated for the mass rearing ofDrosophila suzukii(Matsumura) (Diptera: Drosophilidae) and subsequent production of its parasitoidTrichopria drosophilaePerkins (Hymenoptera: Diapriidae). However, the main problem of the diet was the microbial contamination affecting the batches of good pupae production. Therefore, the concentration of four antimicrobials was optimized through the Taguchi orthogonal array for the inhibition of microbial contamination, identified asPichia occidentalis(Kurtzman et al.) Kurtzman et al. The optimized Taguchi‐selected‐antimicrobials concentrations were 1.33 g l−1of potassium sorbate, 1.33 g l−1of propyl paraben, 1.33 g l−1of sodium propionate, and 0.16 g l−1of triclosan. When the antimicrobials were added to the diet, colony‐forming units ofP. occidentaliswere inhibited by two orders of magnitude. Such inhibition means that theD. suzukiifemales produced 61.1 and 79.3% more pupae and adults, respectively, than the diet with no antimicrobials. These results increase the potential of the wheat germ diet as an artificial diet for mass rearing ofD. suzukiiandT. drosophilae.