Powdery Mildew Of Parsnips – Treating Signs Of Powdery Mildew In Parsnips

Powdery mildew is a very common disease that affects a wide array of plants, usually manifesting in white powdery fungus on the leaves and, occasionally, the stems, flowers, and fruits of a plant. Powdery mildew of parsnips can be a problem if left unchecked. Keep reading to learn more about how to manage and recognize the symptoms of powdery mildew in parsnips.

Symptoms of Parsnip Powdery Mildew

While powdery mildew affects many plants, it can be caused by a number of different fungi, many of which target only certain plants. For example, parsnips with powdery mildew are infected specifically by Erysiphe fungi. Erysiphe heraclei, in particular, is often a culprit. Powdery mildew symptoms start as small, white spots on both or either side of the leaves. These spots spread to a fine, sooty coating that can cover the entire leaf. Eventually, the leaves will turn yellow and fall off.

How to Manage Parsnips with Powdery Mildew

The best method for dealing with parsnip powdery mildew is prevention. Space your parsnips so the leaves of neighboring plants aren’t touching, and plant them in rows so that prevailing winds travel down the rows and provide good air circulation. Allow two years to pass between planting parsnips in the same spot, and plant in soil with a slightly high pH (about 7.0). Remove infected leaves or plants to prevent the fungus from spreading. Spraying preventative fungicides can sometimes be effective, but it’s usually not required if these other less invasive measures are taken. As a rule, parsnips are not especially susceptible to powdery mildew and aggressive fungicide application is not necessary. Some varieties of parsnip are tolerant of the fungus and can be planted as a preventative measure if powdery mildew is a particular problem in your garden.

Liz Baessler
Senior Editor

The only child of a horticulturist and an English teacher, Liz Baessler was destined to become a gardening editor. She has been with Gardening Know how since 2015, and a Senior Editor since 2020. She holds a BA in English from Brandeis University and an MA in English from the University of Geneva, Switzerland. After years of gardening in containers and community garden plots, she finally has a backyard of her own, which she is systematically filling with vegetables and flowers.