Experimental Testing of Host Range of the Parasitoid Wasp Trichogramma dendrolimi Under Laboratory Conditions.

Trichogramma is an important genus of egg parasitoids, applied against agricultural and forest lepidopteran pests. Known species differ in host specificity, which affects both their efficiency in field and suitability for mass rearing. In 2022, a novel strain of T. dendrolimi was recovered from eggs of the Siberian silk moth Dendrolimus sibiricus in Eastern Siberia. Freshly laid eggs of lepidopteran insects belonging to 17 species were exposed to adult T. dendrolimi. Besides the original host, successful reproduction was observed in the eggs of 13 species belonging to the families of Sphingidae (3 species), Noctuidae (2 species), Pyralidae (1 species), Crambidae (1 species), Erebidae (3 species), Gelechiidae (1 species), Geometridae (2 species), Nolidae (1 species), and Lasiocampidae (3 species). The maximum parasitoid yield of 33 adults per egg was observed in D. sibiricus, followed by Dendrolimus pini (32 adults/egg), Macrothylacia rubi (27 adults/egg), Manduca sexta (26 adults/egg), Orgyia antiqua (4 adults/egg), Pseudoips prasinana (3 adults/egg), Mamestra brassicae, Angerona prunaria, and Chrysorithrum flavomaculata (2 adults/egg), as well as Hydraecia micacea, Ostrinia nubilalis, Galleria mellonella, and Sitotroga cerealella (1 adult/egg). Thirty generations were successfully reproduced in the laboratory using D. sibiricus, M. sexta, M. brassicae, and S. cerealella eggs. The parasitoid remained viable and efficiently attacked eggs of various lepidopteran hosts. The present study extends the knowledge of susceptible hosts of T. dendrolimi. Some of these host species provide high reproduction indices of the parasitoid and could be used for large scale propagation of this biocontrol agent.