Nematicidal effect of cell-free culture filtrates of EPN- symbiotic bacteria on Meloidogyne javanica

Biocontrol of plant parasitic nematodes to decrease the chemical pesticides effects is one of the top priorities. Entomopathogenic bacteria, Xenorhabdus spp. and Photorhabdus spp., are important due to production of natural products with antibacterial and antifungal activity. The effect of the cell-free culture filtrates (CFF) of symbiotic bacteria species Xenorhabdus nematophila, X. bovienii and Photorhabdus luminescens isolated from entomopathogenic nematodes Steinernema carpocapsae, S. feltiae and Heterorhabditis bacteriophora on the egg hatching and mortality of the second stage juveniles of root-knot nematode Meloidogyne javanica was determined. Exposure of eggs of M. javanica to CF resulted in the reduced hatching of nematode eggs with higher recorded effect for X. nematophila CF. Analysis of mortality data for juveniles at 24, 48 and 72 h following exposure to CFFs indicated that X. nematophila and P. luminescens were more toxic than X. bovienii after 24 h. However, X. bovienii was more toxic in lower concentration after 48 and 72h post-exposure. Thus, these bacteria have a potential as biocontrol agents for the management of root-knot nematode.

Keywords:

biological control , root-knot nematode , Xenorhabdus , Photorhabdus