Powdery mildew life in the soil - Ask Extension
Hi,I'm wondering how long powdery mildew can live without a crop host. We typically overwinter a variety of brassicas in the field and we're intereste...
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Powdery mildew life in the soil #379357
Asked December 08, 2016, 3:23 PM EST
Hi,
I'm wondering how long powdery mildew can live without a crop host. We typically overwinter a variety of brassicas in the field and we're interested in removing them before the spring planting in order to minimize the spread of powdery mildew. However, we rely on these crops for winter harvest so would like to keep them in the ground for as long as possible. How long should we keep the field free of brassicas to cut down on powdery mildew?
I'm wondering how long powdery mildew can live without a crop host. We typically overwinter a variety of brassicas in the field and we're interested in removing them before the spring planting in order to minimize the spread of powdery mildew. However, we rely on these crops for winter harvest so would like to keep them in the ground for as long as possible. How long should we keep the field free of brassicas to cut down on powdery mildew?
Pierce County Washington
Expert Response
The powdery mildew fungus can survive on living plants or as a sexual spore stage in plant debris. So a plant infected with powdery mildew can be a source of asexual spores (conidia) while alive and then the dead plant remenents can be theoretically infectious until the plant residue breaks down. Exactly how long the powdery mildew fungus survives in plant debris in soil is unclear and probably varies with the crop, cropping practices, and the weather. A good rule of thumb on the powdery mildew is three years, but could be shorter or longer depending on the factors mentioned above.
