North America

How to manage pink rot in potatoes

potato-pink-rotThis pathogen thrives in saturated soils, so the disease is often associated with low spots in the field or in areas of poor drainage. Disease incidence is greatest at temperatures between 70°F and 85°F. You may not notice pink rot until harvest or when the tubers are in storage, but it starts in the field. Infections often originate at the stolon attachment but also may occur at the eyes or through wounds. There are several tell-tale indicators of pink rot, says Carrie Huffman Wohelb, Associate Professor/Regional Specialist – Potato, Vegetable, and Seed Crops, at Washington State University. According to her, the most frequently used oomycete fungicides for managing pink rot in the US are mefenoxam (e.g., Syngenta’s Ridomil Gold, Nufarm’s Ultra Flourish) and metalaxyl (e.g., LG Life Sciences’ MetaStar). Mefenoxam is also known as metalaxyl-M and is chemically similar to metalaxyl. Wohelb warns that growers should be aware of resistance issues. Read more