Potential of Steinernema feltiae (Nematoda: Steinernematidae) Native Populations in the Biocontrol of Lycoriella ingenua (Diptera: Sciaridae) and Their Impact on Mushroom Production

Lycoriella ingenua (Dufour) is a major pest in mushroom facilities in Serbia and worldwide. The study aimed to determine the virulence (in vitro) and effectiveness (in vivo) of three Serbian native populations of entomopathogenic nematodes (EPNs) Steinernema feltiae (Filipjev), P9, K2, and ZŠT, compared to a commercial population of S. feltiae against L. ingenua, and their impact on mushroom yield. In vitro bioassays showed that seven days after exposure to a series of nematode suspensions (IJ cm−2), two of the three native (P9 and K2) populations and the commercial population of S. feltiae caused significant mortality of L4 instar larvae of L. ingenua. The following LC50s were estimated: 18.47, 15.77, and 11.48 IJ cm−2 for P9, K2, and the commercial populations, respectively. These populations were further used for in vivo bioassays, where their IJs were applied as drench treatment twice (at the rate of 75 IJ cm−2) during casing time and seven days later. Control of L. ingenua larvae with the commercial population of S. feltiae was 85%, while the effectiveness of the native populations was 70%. The lack of adequate pest control measures emphasizes a need to promote local EPNs as biologically based and ecotoxicologically safe products.