Infectivity of populations of the entomopathogenic nematodes Steinernema feltiae and Heterorhabditis megidis in relation to temperature, age and lipid content

The infectivity of populations of the entomopathogenic nematodes Steinernem a feltiae and Heterorhabditis megidis from Greece (GR) and the UK was compa red using Galleria mellonella larvae as hosts. Dose-response tests showed t hat the two Steinernema populations did not differ in their establishment r ates but they were more infective than H. megidis UK 211. The temperature r ange for infectivity was greater than that for development. However, the op timal temperature for infection and development for all populations was 23 degreesC. Infectivity of Steinernema populations was not affected by storag e for 12 weeks. However, 12 week-old H. megidis UK 211 infective juveniles (IJ) were less infective than fresh IJ. H. megidis GR showed very low estab lishment rates at all the doses and temperatures tested, before and after s torage. The results are discussed in relation to the nematodes' climatic or igin and lipid content.