Pink rot of potato

Pink rot of potato is a serious soil-borne disease caused by the oomycete Phytophthora erythroseptica. It is a major threat to potato production worldwide, often causing rapid decay of tubers both in the field and during storage.

The pathogen primarily affects potatoes, but it can also impact other solanaceous crops. The fungus survives in the soil through thick-walled oospores, which can remain viable for several years even in the absence of a host crop, complicating long-term soil management.

Diagnostic symptoms are characteristic: when an infected tuber is cut, the flesh appears creamy at first, but within 20-30 minutes, it oxidizes to a distinct pink color. Eventually, the tissue turns brown and spongy, often emitting a vinegar-like or alcoholic odor due to secondary bacterial infections.

Disease development is highly dependent on environmental conditions, specifically high soil moisture and warm temperatures. Poor drainage or waterlogged conditions significantly exacerbate the spread of zoospores, leading to rapid infection of the tubers through eyes, lenticels, or stolon ends.

Management strategies focus on cultural practices, including long rotations of 4 to 5 years without host crops. Essential measures also include planting in well-drained soils, ensuring good sanitation of farm machinery, and keeping storage facilities cool and well-ventilated to inhibit the growth of the pathogen.

• Crop rotation with non-host plants.
• Improvement of soil drainage.
• Culling of infected tubers at harvest.
• Sanitation of equipment to prevent spore spread.