Rachel Penczykowski

Assistant Professor


“Our lab is currently focusing on the interaction between Plantago species and their powdery mildew pathogens along a large latitudinal gradient in the central USA, spanning from northern Minnesota down to the Mississippi Delta area, as well as locally in the St. Louis area. We’re looking at the prevalence of powdery mildew infection on this species. We’ll be sampling infected leaves to quantify the diversity of strains of certain powdery mildew species in the different areas.

One major question I have is how variation of winter along this gradient might be affecting the diversity of pathogen strains. Many powdery mildew species are very host specific, so if their host dies back in winter, they don't have another one they can grow on while they're waiting for their host to reappear. Powdery mildew infections are also occurring on the surface of leaves; they’re not the type of pathogen that can hide out in the rootstock, and come back up through the new above ground growth after. I expect that studying this interaction along a pretty large latitudinal gradient with a lot of environmental variation we will certainly see some very interesting patterns.”

Working in different places, are you collecting from road sites or where?

“I'm primarily targeting county fairgrounds as my sampling locations, at least in the top half of the latitudinal gradient, basically in the Midwest. Almost every county has some designated area where their county fair sets up each year. And then maybe there are some demolition derbies or other exposition-type events that happen at those areas at other points of the year. These fairgrounds are typically the kinds of habitats that my plant species of interest thrive in: they are periodically disturbed, with some open habitats, and somewhat accessible to the public or ecological researchers. Since they're also typically county-owned land, there are contact people that I can find easily to ask permission to sample.”

How do they react to you asking permission to count weeds?

“Usually with some sort of weird facial expression and maybe some sort of joke like, ‘Well you can count my weeds if you tell me how to get rid of them!’ I haven’t had anyone express concern about me wandering through with my field gear and PVC measuring quadrats and hula hoops.”

Hula hoops?

“Hula hoops work well as quadrats too. It's kinda’ fun, if you wanna’ go really random, you can throw them.”

Rachel leads the Plant Disease team. Learn more about their host-pathogen coevolution research here.