Isolation and characterization of two entomopathogenic nematode strains, Heterorhabditis indica (Nematoda, Rhabditida), from the West Bank, Palestinian Territories

Two entomopathogenic nematode strains (Beth 11 and Beth 22) were isolated b y trapping with larvae of Galleria mellonella from soil samples taken from the fields near Bethlehem, West Bank. The total length of the nematode daue r juveniles fall within the description for Heterorhabditis indica. Crossbr eeding experiments confirmed the designation of the new strains to H. indic a. Offspring were recorded when males or females of the Bethlehem strains w ere cultured together with males or females of the H. indica type strain LN 2. No offspring were produced by crosses of the new strains and H. bacterio phora. Sequence analysis of the variable region of the 16S rRNA gene of the symbiotic bacteria Photorhabdus luminescens isolated from the type strain LN2 and other tropical symbionts of H. indica allowed the characterization of a specific group within the species P. luminescens. The symbiotic bacter ia isolated from the Bethlehem nematode strains differ in their sequence an d thus form a distinct group. The West Bank strains of H. indica are more h eat resistant when compared with H. bacteriophora from temperature climatic regions. The LD70 after 26 h exposure to G. mellonella was 25 for Beth 11, 55 for Beth 22 and 160 dauer juveniles for H. bacteriophora. The new isola tes seem better adapted for biocontrol of Maladera matrida than the H. bact eriophora strain tested.