Replant diseases are a common occurrence among many members of the Rosaceae family, including ornamental roses, apples, pears, cherries, peaches, plum, citrus, and raspberries. It is sometimes referred to as “replant syndrome” as it can be caused by a complex of organisms, including plant pathogens and parasitic nematodes, that can vary from site to site, region to region, and crop to crop. In ornamental roses, roots of the plant need only to be growing a few months for the condition to occur such that if the initial plant was removed and another rose planted in the same place, the new plant would not grow well. In apple in Washington State, replant disease developed after the third season of growing apple in a soil that had previously never had apple before. If plants grow better in fumigated or pasteurized soil than the untreated soil, this indicates the presence of a biological factor that is likely a form of replant disease.
Apple Replant Disease
Apple replant disease is experienced in most parts of the world when a new apple planting is made on land just removed from apple production. This occurs as orchards are renewed for new varieties or management systems. The causal organisms for apple replant disease vary by geographic location. In the Pacific Northwest, fungal pathogens are the primary culprits, and nematodes can also be involved. Replant diseases are typically treated by soil fumigation, since the economic losses from no treatment are severe. Research by USDA-ARS (Dr. Mark Mazzola) has focused on alternatives to methyl bromide fumigation and has explored many biological and cultural practices that could also be used on organic farms. Currently both Brassica seed meals and Anaerobic Soil Disinfestation show promise.
Brassica Seed Meal Soil Amendments Transform the Rhizosphere Microbiome and Improve Apple Production Through Resistance to Pathogen Reinfestation. M. Mazzola et al., 2015, Phytopathology.
Advances in Brassica seed meal formulation and application protocol for control of apple replant disease. M. Mazzola poster, December 2010, Wash. St. Hort. Assoc. meeting. A summary of the most recent field results using brassica seed meal mixtures.
Response of ‘Honeycrisp’ apple trees to combinations of pre-plant fumigation, deep ripping, and hog manure compost incorporation in a soil with replant disease. 2010. HortScience 45:1702-1707. Braun et al., AgCanada, Kentville, Nova Scotia.
Potential of Brassicaceae seed meal formulations for replant disease control in organic and conventional orchard systems. A summary of recent findings by Mark Mazzola, USDA-ARS, on the use of brassica meal to control the replant disease complex (fungi and nematodes) in Washington apple orchards.
Other Replant Disease
Both cherries and pears are known to experience replant disease. Planting one type of fruit after another generally does not provide significant control, as the pathogen complex is similar across fruit types.
Non-fumigant options for replant disease/nematode management. Tom Forge, Agriculture and Agrifood Canada, March 2017. Includes on-going trials on replant disease in cherries.
Replant syndrome in fruit trees. David Granatstein, WSU Wenatchee. Discusses some basic information on fruit tree replant disease and examples of control measures.