Disease organisms invade injured tissue and develop cankers that release spores. Some red strains of McIntosh are susceptible, for reasons unknown, to opportunistic diseases that kill branches. Photos courtesy of george sundin, Michigan State University Starting in 2006, an epidemic of sorts started in apple orchards in Michigan. It was a planting epidemic, as some 272,000 McIntosh apple trees of the LindaMac strain and 242,000 of the RubyMac strain were planted. These strains become super-red early and are attractive to growers and consumers for this reason. As these trees moved into their first years of heavy production, a mysterious ailment […]