Rhizosphere colonization and control of Meloidogyne spp. by nematode-trapping fungi

The ability of nematode-trapping fungi to colonize the rhizosphere of crop plants has been suggested to be an important factor in biological control o f root-infecting nematodes. In this study, rhizosphere colonization was eva luated for 38 isolates of nematode-trapping fungi representing 11 species. In an initial screen, Arthrobotrys dactyloides, A. superba, and Monacrospor ium ellipsosporum were most frequently detected in the tomato rhizosphere. In subsequent pot experiments these fungi and the non-root colonizing M. ge ophyropagum were introduced to soil in a sodium alginate matrix, and furthe r tested both for establishment in the tomato rhizosphere and suppression o f root-knot nematodes. The knob-forming M. ellipsosporum showed a high capa city to colonize the rhizosphere both in the initial screen and the pot exp eriments, with more than twice as many fungal propagules in the rhizosphere as in the root-free soil. However, neither this fungus nor the other nemat ode-trapping fungi tested reduced nematode damage to tomato plants.