Within the next two years, Cornell University plant pathologist Herb Aldwinckle hopes scientists and the tree fruit nurseries will have solved the problems of propagating Cornell’s Geneva 41 rootstock—because, he thinks, that rootstock, and maybe others, is the answer to the problems of Malling 9. Malling 9 dwarfs trees to the size that growers want, but the rootstock is susceptible to fireblight infection and to replant disease. Fireblight is an especially severe threat in the Midwest, Northeast, and Mid-Atlantic areas, and replant disease is a major headache in the Pacific ­Northwest. G.41, which is resistant to both diseases and the […]