Diversity of mollusc-parasitic nematodes of the genus Phasmarhabditis. How to identify them?

Abstract: As the mollusc pests cause increasing damage in agriculture and horticulture parasites of molluscs are getting much attention. Phasmarhabditis nematodes as one of the most common slug and snail parasites do not fall behind. P. hermaphrodita is the best known mollusc-parasitic nematode of the family Rhabditidae (Nematoda). However during the last few years several new species from different parts of the world have been discovered and described. Only during the last year four descriptions were published with two species originating from the Czech Republic, one from Italy and one from the USA. Up to these days (January 2017) we know nine species and other new species will probably accrue in the close future.