Clubroot disease, caused by Plasmodiophora brassicae, is becoming increasingly challenging for cruciferous crop production worldwide. The primary outcome of this project will be a clubroot management strategy that integrates non-host cover crops, biological control agents (BCAs) and an ecofriendly soil disinfestation method. Outreach activities will enhance growers’ aptitude to integrate these techniques in their farming systems, which will boost productivity and profitability by minimizing yield losses and dependence on fungicides or soil fumigants and soil liming for disease management. Clubroot is particularly problematic on muck soils in the US Northeast and Midwest due to intensive cultivation and declining soil pH. Most of the currently available management practices disrupt physical, chemical and biological properties of soil or are financially and environmentally expensive. These approaches are also not always effective because of the presence of highly resilient resting spores of the pathogen. However, certain non-host crops can break dormancy of these resting spores in soil, and these germinating resting spores can be killed by abruptly creating an unsuitable environment.
ASD is brought about by incorporation of easily decomposable carbon sources (plant biomass, crop byproducts etc.) into soil, with sufficient moisture to foster microbial activities leading to anaerobicity. ASD alters both chemical and biological properties of soil, which are deleterious to a wide range of crop pests.
Combining ASD with BCAs compatible with the process may provide synergy in P. brassicae population reduction. In this project we will grow non-host cover crops to induce the germination of resting spores and the cover crop biomass will be used as ASD carbon source. Moreover, effective BCAs will suppress the remaining dormant resting spores during the ASD treatment period. The study is expected to provide an effective alternative for organic and conventional growers for clubroot management. On-farm field experiments, field days and a workshop will ensure farmer involvement in the learning process and enable changes in understanding and behavior that will result in sustainable clubroot management. Pre- and post- workshop surveys will be used to evaluate learning outcomes, and publication of a peer-reviewed research article and extension factsheets will be indicators of the quality of project outputs.
Project objectives from proposal:
Outcomes of this project will be helpful to cruciferous crop growers, extension workers and researchers to understand the mechanism and use of non-host cover crops, ASD and biocontrol in clubroot disease management. However, the primary beneficiary will be muck crop growers who have persistent problems with clubroot on their farms.
The learning outcomes of this project are: growers will 1) understand the synergistic roles of non-host cover crops as ASD carbon sources and BCAs in clubroot disease management; and 2) develop the skills to implement these strategies for economically feasible and environmentally safe clubroot management.
The action outcomes of this project are: growers will 1) adopt effective combinations of non-host cover crops, BCAs and ASD to manage clubroot disease; and 2) reduce their dependence on potentially soil damaging fungicides/fumigants and liming practices to manage clubroot.