Infectivity of Bacillus penetrans in plant-parasitic Nematodes

Larvae of Meloidogyne spp. were readily infected with the endoparasite Bacillus penetrans by exposure to an aqueous suspension of spores from infected root-knot nematode females, or by passage of larvae through a shallow layer (50 cm(3)) of spore-infested soil. Infection severely reduced motility of second-stage larvae through soil. Bacillus penetrans exhibited a distinct host specificity in that only 5 of 16 nematode species tested became infected with the population used. Meloidogyne javanica, M. arenaria, and M. incognita became more heavily infected than M. hapla or Pratylenchus scribneri under similar conditions, but all of these species were also good hosts. Ultrastructural changes in the endospore within sporangia adhering to the cuticle are similar to those reported for other germinating Bacillus endospores.