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Influence of Glomus intraradices on Black Foot Disease Caused by Cylindrocarpon macrodidymum on Vitis rupestris Under Controlled Conditions

December 2006 , Volume 90 , Number  12
Pages  1,481 - 1,484

Elsa Petit and Walter Douglas Gubler , Department of Plant Pathology, University of California, Davis 95616

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Accepted for publication 22 May 2006.

We examined the influence of an arbuscular-mycorrhizal fungus, Glomus intraradices (INVAM CA 501), on black foot disease caused by the fungus Cylindrocarpon macrodidymum on Vitis rupestris cv. St. George under controlled conditions. Mycorrhizal or nonmycorrhizal grape rootings were inoculated with the pathogen. Eight months following inoculation with the pathogen, we evaluated disease severity, vine growth, and mycorrhizal colonization. Mycorrhizal plants developed significantly less leaf and root symptoms than nonmycorrhizal plants (P = 0.04 and P < 0.0001, respectively). Only nonmycorrhizal grape rootings inoculated with the pathogen had significantly less dry root and leaf weights compared with the noninoculated control (P = 0.0021 and P = 0.0017, respectively). Mycorrhizal colonization was high (48.3% for the noninfected control and 54.5% for plants infected with C. macrodidymum) and not significantly affected by inoculation with C. macrodidymum (P = 0.2256). Thus, V. rupestris preinoculated with G. intraradices were less susceptible to black foot disease than nonmycorrhizal plants. Results from this study suggest that preplant applications of G. intraradices may help prevent black foot disease in the nursery and in the vineyard.

Additional keywords: endomycorrhizal symbiosis, glomalean fungi, replant disease, vesicular-arbuscular mycorrhizae, Vitis vinifera

© 2006 The American Phytopathological Society