A name you often hear around the Duke Forest office is Charles Mitchell. Whether sending a new student to pick up keys and parking passes, requesting our help to maintain his two study sites, or sending us a list of published papers from his Duke Forest based research, Charles Mitchell is one of our most active researchers. We caught up with him this month to hear more about his work and to share it with our Duke Forest community.
Charles Mitchell, professor of environment and ecology at UNC, and his lab study fungal species that infect, spread, and cause disease in grasses. With many homeowners battling the fungal diseases of “brown spot” and “ring spot” in their yards, you might be curious about their work. The impact of their research extends beyond the front yard, though. Understanding the fungal pathogens that infect grasses and how they interact with each other and their host grass can be used to learn about the spread of other types of infections. Their results have implications for the agricultural industry and also for modern medicine.
Mitchell and his team use community ecology approaches to study how parasitic microbes, like the fungi found in grasses, interact to slow or accelerate spread of disease. While they do so using plants, their research findings can be generalized to animal and human populations through mathematical models.
Close up of grass 
Mitchell Lab’s research area
For a variety of reasons, plants are ideal subjects. “Unlike animals,” Mitchell observed, “plants stay where you put them.” Plants also do not require the same level of ethical and logistical consideration that animals would if they were used to study parasites. In this world of serious research, there is room for simple wonder and curiosity too. Mitchell just loves plants, praising them as “amazing organisms [that] make their own food from sunlight.”
At one of the Mitchell Lab plots in the Duke Forest’s Durham Division, the lab studies tall fescue (Festuca arundinacea) in research that is funded by the US Department of Agriculture for its implications on hay production. Tall fescue is the most abundant plant species in Eastern North America in hayfields, abandoned agricultural fields, and quite likely, in every yard in your neighborhood.
The researchers are primarily studying a fungal species that lives inside tall fescue and helps protect it from things that might want to eat it, like a cow. Cows and other livestock that eat fescue infected with this fungus can become sick with “fescue toxicosis.” Understanding the relationship between fescue and the fungus that lives within it, and how that fungus gets transmitted between plants, is important for protecting the health of livestock and our food systems.
Mitchell and his lab are also using tall fescue to study other common plant infections and to investigate why some epidemics occur each year like clockwork. Such annual epidemics are also important in humans – this is why you’re recommended to get a flu shot each year. Brooklynn Newberry, who manages the Mitchell lab research operations, will soon begin a new phase of the research in which she will intentionally infect plant communities with a pathogen. She’ll do so using a mesocosm system made from plastic kiddie pools. A mesocosm allows researchers to study the natural environment with a greater degree of control over the conditions. In Brooklyn’s case, she’ll be able to use the kiddie pools to isolate and study 40 different plant communities while keeping them separate from other vegetation, which could confuse the results. Newberry says, “It’s like having 40 different communities of humans to control for and study!”
Mesocosms 
Lab Manager Brooklynn Newberry 
Mesocosms
One of the pathogens she will study is familiar to many homeowners frustrated with brown circles in their otherwise green grass. Brown patch is caused by a fungal pathogen that lives in the soil and emerges when it gets warm enough. As the fungal infection grows on the tall fescue and other cool season grasses, it forms the characteristic brown spots and eventually consumes the entire leaf.
For many, it would be hard to imagine that infectious disease research is happening in the fields and forests of the North Carolina Piedmont. We often think that scientists working on infectious diseases are in far flung locations around the globe or suited-up at a research bench, but Charles Mitchell and his lab show that the front lines of this research are also right here in the Duke Forest.
To read more about the Mitchell lab and its work, visit mitchelllab.web.unc.edu