Powdery mildew pathogen from greenhouse plants to mature plants in hopyards

Downy mildew management will remain a major point of focus for Michigan hop growers in 2018, but with damaging powdery mildew infections in 2017, you will need to add new fungicides to your disease management program. The downy and powdery mildew pathogens are completely unrelated and are not generally controlled by the same fungicides; if you have not been applying preventative sprays for powdery mildew, you will need to increase fungicide applications this season.

Use clean planting material when establishing new hop yards since both mildew species are readily spread via nursery stock. Consider purchasing a few plants from prospective nurseries and have them tested for diseases including mildews and viruses before committing to a large number of plants. Additionally, any other signs of poor handling at the propagator level may be used as an indicator of plant quality. Other signs of poor handling include mite or aphid infestations, spray damage or poor root development, and would be grounds for rejecting a delivery of plants.

Read more at MSU Extension (Erin Lizotte)