Fruit Crop Pathologist Talks Disease Pressure

For fruit crops in Wisconsin — think apples and grapes, for example — disease pressure was low compared to prior years. Extension Fruit Crop Pathologist Leslie Holland says this is due to the dry growing season.

But what does it mean for next year’s disease load? She says it’s hard to predict, but she expects pathogen pressure to be weaker at the start of the 2024 growing season.

Holland tells Mid-West Farm Report: “If we’re not having high disease pressure this year, there’s probably going to be less pathogen presence. (That) hopefully means less overwintering of the pathogen, which hopefully means when we start this season off, we have a lower disease pressure because we haven’t had pathogens surviving from last season in a huge quantity or abundance.”

While this year saw low disease pressure, she did respond to some flare ups in vineyards and orchards. Powdery mildew and fire blight thrived on some grape and apple crops, respectively. But most of the calls Holland got were questioning if browning leaves were a result of drought or disease.

“Oftentimes when we see patterns that are across an entire field… it’s more of an abiotic or an environmental stress more so than is a disease,” she says. “Diseases tend to be clumped or patchy in the field.”

Holland drives across the state doing field visits and talking to growers. She also travels to different research stations checking test plots. Visit to find more information on the fruit crop research happening around the state. Whether you are a commercial grower or a beginning gardener, UW’s Fruit Team has resources for you.