Pink rot of potato

Phytophthora erythroseptica is a soil-borne oomycete pathogen that causes a severe disease known as pink rot in potatoes. Taxonomically, it belongs to the class Oomycetes, which are fungus-like organisms that thrive in moist environments and cause significant damage to agricultural productivity worldwide.

The disease primarily affects the tubers, stems, and stolons of potato plants. When an infected tuber is cut and exposed to the air, the internal tissue undergoes a characteristic color change, turning from a creamy white to a salmon-pink shade, and eventually darkening to brown or black as it decays.

The life cycle involves the production of sporangia and motile zoospores, which travel through soil water films to infect the root system and developing tubers. The pathogen overwinters as thick-walled oospores, which allow the organism to survive in the soil for several years, making the elimination of the source of infection quite difficult.

Conditions favoring the development of Phytophthora erythroseptica include high soil moisture levels and temperatures ranging from 15°C to 25°C. Excessive rainfall, over-irrigation, and poor soil drainage are the primary environmental triggers that lead to widespread outbreaks in potato fields during the growing season.

Control strategies focus on proactive management. Growers should prioritize land selection, ensuring excellent drainage and avoiding low-lying areas. Cultural practices such as long crop rotation cycles and the use of certified, disease-free seed are essential. Fungicides specifically targeting oomycetes can be applied as a preventive measure in high-risk areas.

• Implement a minimum 4-year crop rotation to reduce soil inoculum.
• Avoid irrigation practices that result in water saturation of the soil.
• Remove and destroy infected plant debris after harvest.
• Ensure rapid cooling of tubers during storage to inhibit pathogen spread.