Association of plant parasitic nematodes and antagonistic microbes in banana rhizosphere

During random survey, a total of eight plant parasitic nematodes Pratylenchus coffeae, Radopholus similis, Meloidogyne incognita, Helicotylenchus multicinctus, Heterodera oryzicola, Hoplolaimus spp. and Xiphinema spp. were found to be associated with banana rhizosphere. Community analysis was done to identify the proportion of plant parasitic nematode (PPN) assemblages in banana rhizosphere with nematode antagonistic microbes (NAM) were also isolated and identified. Antagonistic micro flora comprising both fungi and bacteria were evaluated against three major PPN on banana with their respective cell free cultures/trapping assay. Among these, Bacillus subtilis, Pochonia chlamydosporia, Pseudomonas fluorescens, Trichoderma viride culture filtrates at 75% exhibited more than 90% mortality of M. incognita juveniles and more than 80% inhibition in egg hatching. The above antagonists also caused significant mortality of R. similis and P. coffeae at the same concentration. P. chlamydosporia and Paecilomyces lilacinus isolates colonized M. incognita eggs and egg masses, leading to egg necrosis. Arthrobotrys oligospora trapped M. incognita juveniles by forming hyphal networks.