Susceptibility of shore fly Scatella stagnalis to five entomopathogenic nematode strains in bioassays

The shore fly, Scatella stagnalis (Fallen) (Diptera: Ephydridae) is an important insect pest of greenhouse crops. We evaluated two different Spanish isolates of entomopathogenic nematodes, Steinernema feltiae (Filipjev) (Rhabditida: Steinernematidae) and Steinernema arenarium (Artyukhovsky) (Rhabditida: Steinernematidae), and two commercially available strains, Steinernema feltiae (Nemaplus((R))stop) and Heterorhabditis bacteriophora (Poinar) (Rhabditida: Heterorhabditidae) (Nematop((R))) against shore flies. In tests conducted in 24-well plate filter paper applied at 5, 11, 22, 44 and 88 nematodes per larva, all nematodes produced significant shore fly larval mortality. The lowest concentration tested was enough to obtain high larval mortality (65.2-87.0%). The nematodes Steinernema feltiae and Steinernema arenarium, which parasitized the shore fly larvae faster, also penetrated in higher number in the shore fly larva (4.6-8.8% penetration rate). In bioassays conducted in algae, Steinernema feltiae, applied at 50 nematodes/cm(2) stop, caused highest (100%) and Steinernema arenarium lowest shore fly mortality (94%). Our results suggest that entomopathogenic nematodes appear feasible for controlling shore flies but further tests are needed to determine their efficacy in the field.