The oak-silkworm egg Antheraea pernyi (Lepidoptera: Anthelidae) as a mass rearing host for parasitoids of the genus Trichogramma (Hymenoptera: Trichogrammatidae)

The acceptance of 40 different strains of 24 Trichogramma (Hymenoptera: Trichogrammatidae) species for oak-silkworm host eggs, Antheraea pernyi Guerin-Meneville (Lepidoptera: Anthelidae) was tested in laboratory experiments. The oak-silkworm, which is commercially used in China to mass produce Trichogramma dendrolimi Matsumura on a large scale, was accepted for egg laying by 10 out of the 24 species tested but only 3 species (four strains of T. dendrolimi, three strains of T. chilonis Ishii and one strain of T. cacoeciae Marchal) successfully completed development to adult emergence. The number of adults emerged per host egg averaged 83.2, 37.0, 42.3, 53.0 for four different strains of T. dendrolimi; 42.5, 10.0 for two strains of T. chilonis; 24.5 and 0 for two strains of T. cacoeciae. Seven other Trichogramma species developed in A. pernyi eggs, but no adult emergence occurred and no emergence holes on the chorion were found. The number of Trichogramma larvae, pupae, and adults together per host egg averaged 81.7 and 67.4 for two strains of T. embryophagum Hartig; 39.0 for T. japonicum Ashmead; 35.0, 16.7, 19.0, 0 for four strains of T. evanescens Westwood; 18.7, 0, 0, 0 for four strains of T. brassicae Bezdenko; 11.5 for T. piceum Dyurich; 76.4 and 23.0 for two unidentified strains collected in apple and vine orchards in Germany, respectively. The following 14 Trichogramma species did not parasitize any A. pernyi eggs: T. atopovirilia Oatman & Platner, T. bourarachae Pintureau & Babault, T. buesi Voegél, T. funiculatum Carver, T. ivelae Pang & Chen, T. meyeri Sorokina, T. minutum Riley, T. nerudai Pintureau, T. nubilale Ertle & Davis, T. ostriniae Pang & Chen, T. principium Sugonjaev & Sorokina, T. pretiosum Riley and two further unidentified strains that originated from France and Switzerland. The results confirmed that A. pernyi is a suitable host for rearing T. dendrolimi and T. chilonis and that the two species T. cacoeciae and T. embryophagum, under optimal conditions, might be possible candidates for rearing.