A New Species of Entomopathogenic Nematode Oscheius anaseuli n. sp. (Nematoda: Rhabditidae) from West Georgia (Caucasus)

A new species of the entomopathogenic nematode Oscheius anaseuli n. sp. was isolated from a soil sample from a nut orchard in the village Anaseuli, Guria Region, West Georgia.Morphological studies were carried out using an optical microscope, which confirmed the anatomy-morphological similarity of the nematode to the genus Oscheius.The main features to assign the new species to the insectivorus-group of the genus are leptoderan bursa and hook-like ends of spicula.Oscheius anaseuli n. sp.characterised by: didelphicamphidelphic reproductive system, six separate lips with one sensilla-like brush on each lip, 8 lateral lines, open bursa and bursal papillae (1+1+1/3+3+ph).The most distinctive morphological feature distinguishing the new species from insectivorus species-group is the presence of 8 ridges and 9 incisures.An updated key to the species of the insectivorus-group is provided.Oscheius anaseuli n. sp. is morphologically most similar to the following species of insectivorus-group: O. colombianus, O. muriophilus, O. punctata and O. insectivorus.As the laboratory studies evidence, the new species has proved to be pathogenic for test insects Galleria mellonella and Tenebrio molitor.The nematodes caused insect mortality after 24 hours, and infective juveniles emerged from insect carcasses 36 hours after the insects died.Nematode inoculation resulted in 63.5% mortality of G. mellonella within 5 days and 100% mortality of T. molitor within 48 hours.The entomopathogenicity of nematodes was evaluated by considering the different effects of nematodes on insects.Nematodes showed the best results against T. molitor.Thus, the new nematode species has potential as a biological control agent.