The lily leaf beetle, Lilioceris lilii (Scopoli) (Coleoptera: Chrysomelidae) is an introduced invasive pest of lilies (Lilium spp.) in North America. Classical biological control using a larval parasitoid, Tetrastichus setifer Thomson (Hymenoptera: Eulophidae), was implemented in 2010 in Ottawa. As the beetle expands its geographic range in North America, it is adding new host plant species to its diet. The objectives of this study were to examine preference of the lily beetle for different host plants and larval performance on those plants. In addition, the ability of T. setifer to find beetle larvae on various plants was also examined. Feeding and oviposition experiments suggested that several novel host plants might be suitable for the beetle: Lilium canadense, Lilium michiganense, Lilium philadelphicum, Lilium superbum, Streptopus lanceolatus and Polygonatum biflorum. Field experiments revealed that the beetle is able to attain enemy free space on some of these novel native host plants.