Increasing resistance by the scab fungus to DMI fungicides means that apple growers need new IPM strategies. A project, funded by the Leopold Center for Sustainable Agriculture, will support 3 years (2006-2008) of research and outreach aimed at developing IPM guidelines for growing disease-resistant cultivars with minimal reliance on conventional pesticides. Our field trial at the ISU Horticulture Research Station is being carried out by M.S. student Adam Sisson on a fully dwarf (M9 rootstock) block of the resistant cultivars Redfree, Liberty, and Gold Rush. These cultivars were among the highest-yielding cultivars in our 10-year field trial at ISU, and received excellent scores from consumers in farmers-market quality tests.
The strategies in the field trial include a warning sytem for the SBFS complex, use of a granulosis virus (Cyd-X) and insect growth regulators against codling moth, and composted wood chips as a soil conditioner and partial replacement for conventional herbicides.
Another aspect of the Leopold Center project involves a pilot program to develop high-quality hard (i.e., fermented) cider from disease-resistant apples. This aspect of the project, which has potential for both value-added production and agri-tourism, is being led by Drs. Lester Wilson and Cheryll Reitmeier of the ISU Department of Food Science and Human Nutrition (FSHN).