Susceptibility of Dalotia coriaria (Kraatz) (Coleoptera: Staphylinidae) to Entomopathogenic Nematodes (Rhabditida: Heterorhabditidae and Steinernematidae)

Dalotia coriaria (Kraatz) (Coleoptera: Staphylinidae) and entomopathogenic nematodes (Rhabditida: Heterorhabditidae and Steinernematidae) are two soil-dwelling biological control agents used to manage western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) and fungus gnats Bradysis spp. (Diptera: Sciaridae) in glasshouses. Growers often use multiple natural enemies to achieve economic control, but knowledge of interactions among natural enemies is lacking. We conducted a laboratory bioassay to test the pathogenicity of four commercially available nematode species—Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhbditidae), Steinernema carpocapsae (Weiser) (Rhabditida: Steinernematidae), S. feltiae (Filipjev), and S. riobrave Cabanillas et al.—to third instar and adult D. coriaria. Third instars were three times more susceptible than the adults to the entomopathogenic nematodes. Mortality for D. coriaria adults and third instars treated with S. feltiae and H. bacteriophora was lower than the mortality for D. coriaria adults and third instars treated with S. carpocapsae and S. riobrave. Neither infective juvenile foraging behavior nor size correlates with D. coriaria mortality. Dalotia coriaria appears to be most likely compatible with applications of S. feltiae and H. bacteriophora.