As reported by Kamil Aşkın Patates Tarımí ve Sanayi sector, potato plantations are commencing. Don’t overlook seed treatment! Later, top-down combat becomes challenging…

Rhizoctonia Root Rot and Black Scurf Disease (Rhizoctonia solani)

Rhizoctonia, commonly found in soil, is a fungal menace causing necrosis wounds on roots and stems, particularly in potatoes. The pathogen overwinters in infected tubers, roots, plant debris, and soil as sclerotia and mycelium. It often passes through unburned residues of wheat and cereals.

Affected roots and stems exhibit reddish-brown necrotic spots known as cancer. Root cancer may lead to symptoms resembling blackleg disease due to stunting of plants and curling of upper leaves. Brown, slightly sunken, distinct-edged lesions develop at the base of the stem and stolons. Severe cases can lead to lesion coalescence around the stem. Subsequently, whitening may occur on stem at soil level, resulting in irregular emergence and gaps.

Chemical eradication is not possible; however, using fungicides can only reduce the damage by suppressing the pathogen. The causative agent of the disease, Rhizoctonia solani fungus, can survive in soil and organic residues for up to 3 years. Depending on the severity, it can obstruct water and nutrient uptake in roots and stems, leading to reduced yield and tuber cracking. Low soil temperature triggers the disease (12-19°C).

In our country, since certified seeds are multiplied by producers 3-4 times, fungal disease is a common problem every year. When necrotic lesions on the surface of the tuber exceed 25% of the skin area and do not come off when rubbed with a finger like coal particles, it is not advisable to use these lots as seed.

The most common combat method is seed treatment before planting. Chemical combat includes the use of fungicides containing Fludioxonil, Penflufen, Pritihocinazole, Flutolanil, Tolclophos methyl, and Bacillus subtilis to suppress the disease.

Information is advisory in nature.

I would appreciate contributions from companies regarding innovations, new products, and active ingredients in combating the disease…

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Viktor Kovalev CEO
POTATOES NEWS Viktor Kovalev is the founder of Potatoes.News and the creator of the International Potato Tour (IPT) — a global multimedia project that connects potato farmers, processors, researchers, and agribusiness companies across more than 20 countries. Viktor writes about potato production, processing technologies, storage, seed breeding, export markets, innovations, and sustainable agriculture. His work combines journalism, field research, and video storytelling, giving readers and viewers a unique perspective on the global potato industry. Areas of expertise: Global potato market trends Seed potato production and certification Potato processing (chips, flakes, fries, starch) Smart farming and agri-technologies Storage, logistics, and export Interviews and field reports from leading producers