EFFECT OF TEMPERATURE ON THE PATHOGENICITY OF MEDITERRANEANNATIVE ENTOMOPATHOGENIC NEMATODES (STEINERNEMATIDAEAND HETERORHABDITIDAE) FROM NATURAL ECOSYSTEMS

Abstract

Seven strains of entomopathogenic nematodes (EPNs) belonging to three species (Steinernema feltiae, S. ichnusaeandHeterorhabditis bacteriophora) naturally isolated from Mediterranean countries (Southern Italy and Lebanon) wereevaluated for their potential to infest greater wax moth (Galleria mellonella) larvae at different temperatures underlaboratory conditions. The laboratory bioassay was conducted at six different temperatures ranging from 10°C to 35°C.Nematode Infective Juvenile (IJs) were put in contact with G. mellonellalarvae in Petri dishes and mortality rates wererecorded after 72 hours. The purpose of the study was to evaluate the temperature range in which the EPNs caused larvalmortality; higher mortalities were recorded at 15°C and 20°C. All species failed at lower temperatures except for S.ichnusaeItS-SAR4, which caused 7% mortality. At 35°C S. ichnusaemaintained its infectious activity (24%) along withH. bacteriophora ItH-LU1(38%); both were isolated from Italy and were more efficient at high temperatures than theremaining Lebanese isolates.