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Interactions Among a Soil Organic Amendment, Nematodes, and the Nematode-Trapping Fungus Dactylellina candidum

December 2006 , Volume 96 , Number  12
Pages  1,388 - 1,396

B. A. Jaffee

Department of Nematology, University of California, Davis 95616-8668

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Accepted for publication 10 July 2006.

When alfalfa leaves (Medicago sativa) are added to soil, both the nematode-trapping fungus Dactylellina candidum and microbivorous nematodes increase. To determine whether the response of the fungus to alfalfa depends on consumption of bacterivorous and fungivorous nematodes, soil microcosm experiments were performed. D. candidum did not increase if alfalfa leaves were added to soil lacking nematodes, but did increase if nematodes were added to soil lacking alfalfa leaves. Although these results indicate that the response of D. candidum to alfalfa depends on nematodes, D. candidum and microbivorous nematodes did not exhibit classical predator-prey dynamics (i.e., D. candidum seldom reduced numbers of resident nematodes and, after initially increasing in alfalfa amended soil, numbers of D. candidum then decreased, whereas numbers of nematodes continued to increase). Fungivorous nematodes were abun dant in alfalfa-amended soil, and their potential to suppress trapping fungi requires more research.

Additional keywords: Arthrobotrys oligospora, bacterivorous nematodes, Hirsutella rhossiliensis, litter mass loss, organic amendments, saprophytic competition.

© 2006 The American Phytopathological Society