Submitted to: International Congress of Plant Pathology Abstracts and Proceedings
Publication Type: Proceedings
Publication Acceptance Date: December 1, 2002
Publication Date: April 1, 2003
Citation: MAZZOLA, M. MANAGEMENT OF SOIL MICROBIAL ANTAGONISTS AND INTEGRATED METHODS FOR CONTROL OF APPLE REPLANT DISEASE. INTERNATIONAL CONGRESS OF PLANT PATHOLOGY ABSTRACTS AND PROCEEDINGS. 2003. p. 51. Technical Abstract: Apple replant disease is a significant impediment to the establishment of viable orchards on sites previously planted to the same or related crop. In Washington, a comprehensive study of disease etiology demonstrated that a complex composed of Cylindrocarpon destructans, and multiple species of Phytophthora, Pythium and Rhizoctonia, occasionally in concert with Pratylenchus penetrans, is the primary cause of growth retardation. In greenhouse trials, cultivating orchard soils with wheat prior to planting apple reduced infection by elements of the fungal complex, and induced soil suppressiveness to R. solani AG 5. The response occurred in a wheat genotype-specific manner and was associated with increased recovery of specific fluorescent pseudomonad genotypes that exhibited in vitro antagonism toward R. solani. When used in conjunction with wheat cropping, application of Brassica napus seed meal provided effective disease control in greenhouse and orchard settings, but the growth response was dependent on application sequence. Control of R. solani was obtained regardless of seed meal glucosinolate content. In field trials, modifying the spatial pattern of the orchard or excavation and disturbance of soil in the fall prior to planting significantly improved growth and yield of Gala on M26 rootstock. Trees treated with the narrow-spectrum biocide metalaxyl in combination with flutolanil provided fruit yields that equaled that obtained through pre-plant soil fumigation with methyl bromide. These studies suggest that a viable systems approach to the management of apple replant disease is attainable, which does not incorporate pre-plant soil fumigation and is suitable for both organic and conventional production methods.