Replant Disease is a widespread problem in intensive tree fruit and nut growing areas. It is characterized by reduced productivity in fields repeatedly planted to the same or closely related tree fruit or nut crops. It can also occur in tree fruit and nut nurseries.
Apple Replant Disease (ARD), has biological factors include a complex of several fungal pathogens including Cylindrocarpon, Phytophthora, Pythium spp. and Rhizoctonia, as well as parasitic nematodes and bacteria. Apple trees that do not establish well or fail to establish when planted on a site previously grown with apples are often considered to be suffering from apple replant disease. Although thought to occur in sites replanted after removing very old fruit trees, replant disease has been documented to occur within three years of establishing an orchard on new ground. The causes and symptoms of replant disease vary from region to region and even from site to site. Biological factors play a major role in this disorder.