Nematicidal activity of entomopathogenic bacteria against root-knot nematodes, Meloidogyne incognita in-vitro.

The in-vitro experiment was conducted to evaluate the nematotoxic activities of the cell-free conditioned media (CFCM) of entomopathogenic bacterium species Photorhabdus luminescens (strain: TT01), Xenorhabdus budapestensis (strain: AF 2013 or EMA) and X. szentirmaii (strain: EMC), isolated from entomopathogenic nematodes Heterorhabditis bacteriophora and Steinernema bicornutum and S. rarum, respectively. The applied doses were 1, 2, 5, 10, 20, 40, 60 and 80 V/V %, respectively. The test organism was Meloidogyne incognita (J2s) and the rate of mortalities were determined at the 6th, 12th, 24th and 48th hrs following exposure. Data revealed that the rate of larval mortality proved dose/dependent. Only the highest dose of TT01 CFCM resulted in 100% mortality rate after 48 hrs of exposure time. On the other hand, lower concentrations of EMA and EMC CFCM resulted in the same results. 6 hrs following application of 10 %, CFCM resulted in significantly the highest larval mortality rate 59.4%; in comparison with EMA (48 %) and TT01 (40%).