This article, originally posted in 2021, was updated in January 2024.

Pink rot, a devastating and persistent disease, can wreak havoc on your potato crop. But with the right management techniques, the threat can be suppressed or greatly reduced.

Key to everything, though, is understanding and assessing risk.

Profile of a potato pathogen

Pink rot is caused by Phytophthora erythroseptica – a fungal blight that thrives in damp conditions and affects both plants and tubers.

Pink rot uses a network of fine white filaments (called mycelia) to house overwintering spores. These spores – which can survive in the soil for up to seven years – swim through watery films within or on top of the soil to infect potato stems, stolons, and roots. Once a plant is infected, the pathogen can travel to and grow in tubers; tubers can also be infected through the eyes and lenticels. 

Infected tubers often decay during harvest and handling. Unfortunately, this gives the pathogen opportunity to spread to healthy tubers during storage, which is bad news for yield and product marketability. Even a tiny number of infected potatoes can result in substantial storage losses. 

Keep an eye out

Pink rot infection happens below the soil surface, and that can make symptom identification difficult. However, there are some tell-tale signs your crop is in trouble, including:

• Late-season wilting
• Formation of aerial tubers
• Brown skin spots on tubers
• Mushy tuber flesh that turns pink when cut
• Clear distinctions between healthy and diseased parts of infected tubers

No field is immune

Every field has the potential for pink rot, meaning proactive management is critical. Problems should be addressed before the disease infects tubers – especially when growing more susceptible potato varieties.

Prevention and suppression

A proactive, multi-pronged approach is the most effective way to manage pink rot while maintaining crop yield and quality. 

Cultural management strategies include:

• Rotate to non-host plants (like cereals or corn) to reduce the disease’s spread.
• Understand your variety’s susceptibility to pink rot. Choose less susceptible varieties if risk is high.
• Ensure planted seed is disease-free.
• Work for good skin set prior to digging. This reduces handling damage and enhances storability.
• Plant and harvest in dry soil conditions whenever possible.
• Avoid harvesting from wet or flooded areas in your field.

Syngenta has two options available for the 2024 growing season (one a seed treatment and the other an in-furrow treatment) that can be used separately or in combination to help manage pink rot. 

• Vibrance^® Ultra Potato seed treatment includes mandiprpamid (roup 40) to help protect against pink rot, plus two additional modes of action – difenoconazole (Group 3) and sedaxane (Group 7) – to provide early-season protection from key seed- and soil-borne diseases while preventing storage break-down.
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• Orondis^® Gold Potato in-furrow fungicide combines two powerful active ingredients – oxathiapiprolin (Group 49) and metalaxyl-M (Group 4) – to help protect potatoes from pink rot, as well as Pythium leak. 

Note that oxathiapiprolin is not cross-resistant to any other fungicide on the market and introduces a novel mode of action to combat pink rot. However, it must be used properly to reduce the risk of pathogen resistance. 

Some resistance management practices for Orondis Gold Potato include:

• Applying as part of a preventative disease control program.
• Not following soil application with foliar applications of this or other products containing oxathiapiprolin (such as Orondis Ultra). Plant and harvest in dry soil conditions whenever possible.

​​​​​​​Always read and follow label directions. Orondis Gold Potato is an in-furrow application of Orondis Gold Potato A 200SC and Orondis Gold Potato B 480SL. Orondis^®, Vibrance^® and the Syngenta logo are trademarks of a Syngenta Group Company. © 2024 Syngenta