In an ongoing study, pasteurizing the soil in a replant-affected orchard caused significant improvements in plant growth. Mazzola has found two bacterial organisms that show promise in controlling apple replant disease in the greenhouse. We are still in the early stages of our evaluation trials and need additional trials of the organisms under field conditions. David Granatstein of Washington State University, is working with us to test the organisms in commercial orchards. Mazzola is also working with Andre Levesque, Agriculture and Agri-Foods Canada, Summerland, British Columbia, on seasonal fluctuations in the species composition of Pythium populations.
Pythium is one of the fungal agents that cause replant disease in apple.
In seeking different alternatives, Mazzola and colleagues have made some interesting discoveries about rotating wheat in replant soil. Mazzola plans more research on using wheat as a cover crop. He planted an initial field trial this season.