Why some plant diseases thrive in urban environments

by Chris Woolston, Washington University in St. Louis
June 13, 2024

Something about city life seems to suit powdery mildew, a fungal disease that afflicts many plants, including leaves of garden vegetables and roadside weeds.

Rachel Penczykowski, an assistant professor of biology in Arts & Sciences at Washington University in St. Louis, and five WashU graduate and undergraduate students tracked infestations of powdery mildew on common broadleaf weeds. Their study, published in the journal Ecology, covered 22 sites in the St. Louis area ranging from the rural environment of Shaw Nature Reserve near Gray Summit to Forest Park in the heart of the city.

Penczykowski and her team found a strong and surprising pattern: Weeds in the city had significantly more mildew than the weeds in the suburbs or countryside. “Now we need to figure out what’s driving those patterns,” she said.

While the particular fungus the team studied is harmless to other plants or animals, different species of powdery mildew can be a major threat to vegetable gardens, flowers and vineyards, said Quinn Fox, a 2023 PhD graduate and the study’s lead author. “It’s a big concern in different agricultural industries,” Fox said.

Keep reading: https://source.wustl.edu/2024/06/why-some-plant-diseases-thrive-in-urban-environments/

Read the Ecology paper: https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1002/ecy.4313