Selection of Effective Species or Strains of Trichogramma Egg Parasitoids of Diamondback Moth

Twenty-seven Trichogramma and Trichogrammatoidea species or strains of different origin were tested on diamondback moth (Plutella xylostella (L.)) for host acceptance and host suitability. The experiments were conducted at 27 ± 2oC and 75-90% RH. Depending on their initial parasitization activity, the number of offspring produced and emergence ratio, 18 Trichogramrna species were identified as parasitoids of diamondback moth. Twelve Trichogramma species were compared by host preference experiments. None of the Trichogramma species showed host preference for diamondback moth over i ts laboratory rearing host Corcyra cephalonica Stainton, but differences between the species were found. The parasitization rate of diamondback moth eggs ranged between 0.47 for Trichogramma semblidis and 25.67 for Trichogrammatoidea bactrae. Seven out of twelve Trichogramma and Trichogrammatoidea species (T. bactrae, Trichogramma sp. (France), T. principium, T. pretiosum, T. leptoparameron, T. chilonis, T. confusum, T. ostriniae) showed promise for further investigation into selecting a biological control agent against diamondback moth. Three Trichogramma species were checked in cage experiments. T. pretiosum showed good searching capacity and percentage of parasitism (9.45/34.09%) compared to Trichogramma sp. (France) (2.51 19.26%) and T. leptoparameron (0.125/2.5%).