Interrelations between Meloidogyne javanica, Rotylenchulus reniformis, and Rhizobium Sp. on Vigna sinensis


  • A. H. Y. Taha
  • A. S. Kassab


The interactions of Meloidogyne javanica, Rotylenchulus reniformis, and Rhizobium sp. on cowpea seedlings were investigated. Upon simultaneous inoculation with the two nematode species, M. javanica invaded first but did not affect root invasion by R. reniformis. M. javanica populations increased less in competition with R. reniformis than when present alone. Preinvasion by R. renilormis significantly suppressed the number of M. javanica in the roots. Inoculation of M. javanica and/or R. reniformis with rhizobia did not affect nodulation. Nodule formation was hindered only when R. reniformis infection preceded rhizobial inoculation. Nitrogen nodules were formed on M. javanica galls. Nodules and M. javanica galls served as infection sites for both nematodes. Although R. reniIormis on the roots reduced the space for M. javanica infection, M. javanica is more competitive than R. reniformis and ultimately predominates as a result of its higher reproductive potential and shorter time spent in the soil before infection. Key Words: root-knot nematode, reniform nematode, legume, cowpea, bacterial nodulation.