Growing scab-resistant apple cultivars on fully dwarfing rootstocksincreasesthe feasibility for producing organically grown apples in the Midwest. However, in an organic orchard, fruit thinning to optimize crop load must be done by hand at a very high labor expense or biennial bearing and inconsistent supply to meet consumer demandsis accepted. In 2011, a study was undertaken to evaluate the effectiveness of liquid lime sulfur alone and in combination with spray oil applied at various times during bloom on thinning three scabresistant apple cultivars under Iowa conditions, and was reported in the 2011 Annual Progress Reports for the ISU Horticulture Research Station (ISRF11-36). This report summaries the effect of those treatments on the return bloom in 2012.
Iowa State University
Domoto, Paul A.; Katuuramu, Dennis; Nonnecke, Gail R.; and Schroeder, Lynn R., "Effect of Lime SulfurThinning Sprays on Return Bloom of Scab-resistant Apples" (2013). Iowa State Research Farm Progress Reports. 1910.