VIEW ARTICLE

A Survey of Biotic Relationships in Grape Replant Situations. D. R. Deal, Graduate student, Department of Plant Pathology, Cornell University, Ithaca, New York 14850, Present address of senior author: Department of Science, Glenville State College, Glenville, West Virginia 26351; W. F. Mai(2), and C. W. Boothroyd(3). (2)(3)Professors, Department of Plant Pathology, Cornell University, Ithaca, New York 14850. Phytopathology 62:503-507. Accepted for publication 13 July 1971. DOI: 10.1094/Phyto-62-503.

Bacteria and fungi were more numerous around grape roots growing in replant soil than around those growing in “fresh” nonvineyard soil or rested vineyard soil. Species of Penicillium, Fusarium, Gliocladium, and Roesleria hypogaea were most commonly isolated. A fluorescent species of Pseudomonas was present in the wood of grape roots of high, medium, and low-vigor and dead roots. Amending vineyard soil with pieces of old grape roots suppressed populations of Penicillium spp., increased populations of Tricoderma viride, and improved growth of grape seedlings; roots of the seedlings had much greater development of endophytic, phycomycete mycorrhizae than those grown in soil minus the old roots. Fertilization did not overcome effects of specific replant disease of grape.