Assessment of potential non-target effects of Tetrastichus julis, a biological control agent of the cereal leaf beetle, Oulema melanopus

The cereal leaf beetle, Oulema melanopus (L.) (Coleoptera: Chrysomelidae), is an emerging pest of cereal crops in the Prairie Provinces of Canada. In other regions with a history of this pest, it is managed primarily through biological control with the parasitoid Tetrastichus julis (Walker) (Hymenoptera: Eulophidae). In this paper we report a study conducted during the summers of 2007 and 2008 in Pullman, Washington (USA), and 2010 and 2012 in Lethbridge, Alberta (Canada) assessing potential non-target effects of T. julis. The chrysomelid species tested included the following native and introduced species of leaf beetles (Chrysomelidae): Cassida azurea Fabricius, Chrysolina quadrigemina (Suffrian), Crioceris duodecimpunctata (L.), Deloyala guttata (Olivier), Galerucella calmariensis (L.), Gastrophysa cyanea Melsheimer, Gastrophysa polygoni L., Jonthonota nigripes (Olivier), Lema daturaphila Kogan & Geode, Leptinotarsa decemlineata (Say), Lilioceris lilii (Scopoli), and Xanthogaleruca luteola (Muller) (Coleoptera: Chrysomelidae). Tetrastichus julis did not parasitize any of these potential non-target species. Thus the occurrence and relocation of T. julis in the Prairie Provinces of Canada and northwestern USA poses a relatively low risk to biodiversity.