Sep 6, 2022Potato pink eye concerns in Columbia Basin
The late season hot weather in the Columbia Basin is concerning for pink eye, particularly for Clearwater Russet, Russet Burbank, Russet Norkotah, and Yukon Gold potatoes that seem to be more susceptible to this disorder.
Pink eye is a physiological disorder associated with excessive soil moisture (above 95% available soil moisture) and high soil temperatures (above 70° F), which can result in anaerobic conditions around the tuber during the latter stages of potato growth. The lack of oxygen and heat stress result in damage to the cells that produce the tuber skin (periderm). The damaged areas usually start out as pink, water-soaked areas around the eyes, but then mature to thickened, corky patches, cracks, and sunken areas with an underlying layer of necrotic, reddish-brown tissue.
Pink eye and tuber rots
Pink eye is not caused by pathogens, but the anaerobic conditions that lead to pink eye tend to favor the pathogens that cause tuber-rotting diseases like bacterial soft rot, pink rot, and pythium leak. The compromised tuber skin is an easier route to infection for pathogens that usually only find entry via wounds. This explains why pink eye is often association with tuber diseases.
Monitoring soil moisture levels
Pay close attention to soil moisture levels to minimize both pink eye and tuber rotting disease. Monitor soil moisture levels daily and avoid overwatering. The water needs of the plant decrease significantly when the vines and roots are senescing, so irrigation should be adjusted accordingly. In the last several weeks of growth, allow soil moisture to deplete to 70-75% of the available water-holding capacity before irrigating. Be careful, however, not to overly dehydrate tubers right before harvest, especially if the cultivar is susceptible to blackspot bruise.
Canopy cover helps
A full canopy shades the soil and helps to moderate soil temperatures, and it uses more water. Pink eye and tuber rotting disorders are often associated with early vine senescence when the weather is still hot and there is a tendency to overwater.
If you want to learn more about pink eye, then read this article Potato Pink Eye: A Disorder Growers Need to Watch Out For.
– Carrie H. Wohleb, Extension specialist, Washington State University
Symptoms of potato pink eye. Photo: (top and lower left) A. Robinson, North Dakota State University; (lower right) Jordan Eggers, Oregon State University