Using ‘New' Alternatives to Enhance Adoption of Organic Apple Production through

Organic apple production in the eastern United States is significantly influenced by cultivar susceptibility to apple diseases because of the weather conditions during the growing season. In New England there has been a recent shift away from McIntosh, the historically predominant cultivar which is very susceptible to apple scab to newer cultivars.  This shift is due to consumer preference and a shift in market focus from wholesale to more profitable retail and niche markets. A multi-disciplinary, multi-state long-term research project, OrganicA Project, was initiated in 2006 at the University of Vermont.  One objective of this project is to incorporate and evaluate new apple cultivars and research-generated knowledge of apple ecosystem dynamics into organic production systems to determine their sustainability and profitability.  We are examining two major production systems growers would use in changing cultivars: establishing a new orchard (Orchard 1) and top-grafting an existing orchard (Orchard 2) to the following cultivars: Zestar!, Ginger Gold, Honeycrisp, Liberty, and Macoun.  During the establishment years of these orchards, we collected horticultural data on tree growth and survival, blossom density, and fruit yield.  In Orchard 2, initial survival of new grafts was very good for most varieties (94-100%) except Zestar! which had only 84% of trees with at least one live scion in one year after grafting. By the end of 2008, many Zestar! trees, and to a lesser extent, Macoun trees were completely dead or of such low vigor they would not be profitable for commercial production. Growers who choose to top-graft an orchard rather than remove trees and plant a new orchard do so under the conventional wisdom that bypassing a two year fallow period followed by three establishment years for the new trees will give them a marketable crop sooner.  Preliminary results indicate that poor survival of top-grafted trees may negate the benefit of earlier production for particular cultivars. Differences in precocity occurred in both orchard systems.  In Orchard 1, Zestar! developed more flower clusters in 2007.  In Orchard 2, Ginger Gold, Zestar!, and Liberty exhibited much higher flower density, indicating that these trees have the potential to bear commercial crops earlier and therefore may be more profitable to the grower.