Suitability of European Trichogramma Species as Biocontrol Agents against the Tomato Leaf Miner Tuta absoluta

The tomato leaf miner Tuta absoluta, originally from South America, is an invasive species threatening European tomato crops. Since various insecticides have become ineffective in controlling T. absoluta, effective and environmentally friendly alternatives are needed. Biological control, especially by Trichogramma parasitoids, is considered to be an effective means of reducing this pest. Thus, the aim of our study was to identify promising candidates of Trichogramma parasitoids for biological control of T. absoluta in Europe. We assessed the efficiency of nine European Trichogramma species and compared them to Trichogramma achaeae, as this species is already commercially available. Firstly, we verified species identity of the 10 rearing strains using molecular and morphological methods. Then, host acceptance, host preference (T. absoluta vs. rearing host Sitotroga cerealella eggs) and host searching capacity were tested under laboratory conditions. Our results indicated that T. nerudai, T. pintoi and T. cacoeciae achieved a similar level of parasitism on potted tomato plants as T. achaeae. For the next step, these promising strains should be tested under greenhouse conditions.