Applied Ecology and Management of Diseases Caused by Soilborne Fungi
We aim to improve management by understanding pathogen ecology to refine the timing of fungicide applications, target the survival of soil borne pathogen resting structures and infested residue, and to alter abiotic conditions that lead to disease development.
Current projects include collaborative work in California potato systems to enhance management of Southern blight, a yield limiting disease of annual crops caused by the soil borne pathogen, Athelia rolfsii. We are evaluating the effect of solarization and soil amendments on the viability of A. rolfsii sclerotia. Additionally, we have made strides to improve chemical control by identifying key late season application windows prevent tuber rots caused by A. rolfsii.
In the Great Lakes Region, we are working with multi-state collaborators to evaluate chemical application timings and active ingredients to better manage Phomopsis stem canker of sunflower, a ubiquitous and yield-limiting disease of sunflower.
We are further exploring questions related to the impact of soil health health practices, such as cover cropping, on pathogen inoculum densities, pathogen survival, and pathogen-associated microbial communities.
Pathogen Epidemiology and Climate Adaptation
Changing patterns in temperatures and precipitation alter disease dynamics and agronomic management strategies.
Megan is continuing work to develop lab and field based models to predict the development of Southern blight, caused by Athelia rolfsii, in California. This heat-driven disease limits the yields of potato, sunflower, processing tomatoes and other annual crops. It develops incrementally, when conditions are favorable, and we aim to forecast disease risk so that growers can optimize management.
In Minnesota, growers are experiencing dryer than average summers with a higher intensity of rainfall events in the spring and fall season. Irrigated acreage is increasing with less predictable rainfall and dryer summers. We are interested in the interaction of irrigation and disease dynamics and disease development and forecasting in the context of a changing climate.
Phomopsis stem canker
Sunflower Sclerotinia inoculations
Sclerotinia sclerotiorum Biology and Virulence Factors
Sclerotinia sclerotiorum is a widely distributed soil-borne plant pathogenic fungus that causes yield losses in hundreds of dicotyledonous plant species. In Minnesota, important hosts include soybean, sunflower, dry bean, and canola. Management is complicated by its wide host range and persistent dormancy in soil. Our work aims to characterize aggressiveness determinants across crop species using multi-crop screenings and genetic strategies to elucidate differential and conserved virulence factors accross crops. We will use biotechnological approaches (such as RNA interference) to target virulence factors with the aim of developing tools to enhance crop protection.
Multi-prong Approaches to Enhance Host Defenses and Disease Escape Mechanisms
We aim to improve plant defense strategies by targeting the aforementioned pathogen virulence factors using gene silencing strategies and by considering disease escape mechanisms that interact with pathogen biology. Current work, funded by the Minnesota Soybean Research and Promotion Council and in collaboration with Dr. Aaron Lorenz' breeding program, investigates the interaction between plant architecture and abiotic conditions that are important for the development of S. sclerotiorum. A better understanding of plant phenotypes that escape infection by S. sclerotiorum may lead to additional tools for breeders to enhance host defense of soybean against S. sclerotiorum.