Submitted to: International Conference on Methyl Bromide Alternatives and Emissions Reductions
Publication Type: Proceedings
Publication Acceptance Date: 6/1/2003
Publication Date: 11/3/2003
Citation: Mazzola, M. 2003. Non-fumigant measures and assessment of host tolerance for replant disease control. International Conference on Methyl Bromide Alternatives and Emissions Reductions. pp. 9.1-9.3.
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. Biologically-based alternatives are being developed to control the causal disease complex composed of Cylindrocarpon destructans, and multiple species of Phytophthora, Pythium and Rhizoctonia, occasionally in concert with Pratylenchus penetrans. In field trials, one year cultivation of orchard soils with wheat prior to planting apple reduced infection by elements of the fungal complex and increased yields of Gala/M26, however the growth improvement was inferior to that obtained in response to pre-plant methyl bromide fumigation. B. napus seed meal amendment in conjunction with a Ridomil soil drench and Telone-C17 soil fumigation were effective in controlling the pathogen complex that was targeted at two replant sites. Over the initial 2-year life span of the CV orchard, growth and yield of Gala/M26 planted in seed meal-Ridomil treated soil has been equivalent to or exceeded that of trees established in fumigated soil. On a site possessing the lesion nematode as a component of the disease complex, growth attained using this alternative treatment was improved but was inferior to pre-plant fumigation. The seed meal-Ridomil treatment suppressed root populations of the nematode during the initial year but nematode numbers recovered during the second growing season. This resulted from nematode migration indicating a need for seed meal incorporation to greater soil depth.