Poland: Potato blight 2025 already in Polish fields! Time for protection!

Phytophthora infestans can quickly lead to catastrophic losses if appropriate measures are not implemented. The disease attacks not only the leaves but also the stems and tubers of potatoes, leading to a loss of commercial value and quality of the crop. Find out if potato blight 2025 can be controlled.

Potato blight 2025 - weather favors infection

This year’s weather conditions may mislead many farmers. Namely, it seems that in dry and warm weather, plants are generally safe. Nothing could be further from the truth. In such conditions, the potato plant is very weakened and therefore extremely susceptible to even a minor infection.

Meanwhile, such an event could have occurred in recent hours. Because high air humidity and relatively mild temperature are the ideal environment for rapid activation of infectious spores of Phytophthora infestans (the cause of potato blight). And we are dealing with such spores in southeastern Poland after several hours of heavy rainfall. In addition, professional potato producers irrigate plantations. With sprinkler irrigation, it is very easy to infect plants.

Conditions favorable for the development of potato blight : air temperature from 3–29°C (optimum 16–21°C); relative air humidity above 90%.

It is enough to “let go” of the infection at a critical moment, followed by a few days of undisturbed pathogen development, and the disease can spread rapidly across most of the field.

That is why we are warning - the potato blight 2025 is already being signaled. The following provinces are warning about its occurrence: Pomeranian, Świętokrzyskie, Małopolskie. Remember, the lack of proper protection can lead to losses exceeding 50% of the tuber yield.

Potato blight symptoms that should cause concern

During this time of the growing season, potato blight symptoms appear on leaves as small, irregular, light green or brown spots. Over time, the spots turn brown and are often surrounded by a yellow or light green border.

Potato blight 2025 is reported on plantations. Its symptoms are spots and necrosis

photo: Katarzyna Kupczak

Particularly characteristic is the white, velvety coating on the underside of the leaf, visible especially in the morning or in humid weather. In case of intensive infection, the coating may also appear on the upper side of the leaf.

Dark, brown streaks also form on the stems. Their expansion around the shoot leads to wilting and breakage.Then the disease takes over the tubers. Its symptoms are gray-blue, slightly sunken spots of irregular shape. Within these discolorations, the flesh takes on a brown-reddish color.

Time to Fight Potato Blight - How to Effectively Protect Potatoes?

The most important thing is monitoring the plantation. In addition, it is worth listening to all the signal messages from the area. It is also worth remembering that the source of infection is:

• waste piles,
• neighboring crops, including field tomatoes
• infected seed potatoes,
• self-seeding in subsequent crops,
• soil.

In plantation protection, the most important thing is to quickly apply fungicides with systemic or deep action. It is best in mixtures that work, firstly, by protecting against the penetration of the perpetrator into the plant and eliminating germ hyphae inside it. Secondly, they combat various stages of pathogen development.

It is recommended to rotate plant protection products to prevent pathogen resistance.

The most effective fungicides protecting both the above-ground part and the tubers are listed below. We decipher them by providing the trade names of the fungicides that contain these substances:

• amisulbrom - Ami4Fungi 200 SC, Gachinko, Genkotsu, Leimay 200 SC, Leomin 200 SC;
• cyazofamide - Ranman Top 160 SC, Azuleo, Dynox 160 SC, Karitsu, Livarti, Sugoi;
• cymoxanil - Controlla 450, Curzate 60 WG, Cymbal Flow, Dauphin 45 WG, Drum 45 WG, n Drum Flow, IMOX 45 WG, Krug Flow, Moxato 450 WG, Sacron WG, Veludo 450 WG;
• cymoxanil + fluazinam — Grecale, Kunshi 625 WG, Plexus, Tezuma 625 WG,
• fluazinam - Altima 500 SC, Banjo 500 SC, Dalimo, Fluazin 500-I, Fluazin 500-III, Fluazinova, Innzar 500 SC, Kelsos 500 SC, Magic, Nando 500 SC, Pyrol 500 SC, Winby, Zignal 500 SC;
• mandipropamid - Revus 250 SC, Mandius 250 SC, Revolte 250 SC,
• mandipropamide + cymoxanil - Carial Flex,
• mandipropamide + difenoconazole - Carial Star 500 SC,
• oxathiapiproline - Zorevec Enicade, OKSA4FUNGI 100 OD, Zertan;
• oxathiapiproline + amisulbrom — Zorevec Entecta, Sopolet;
• pyraclostrobin - in Poland a substance found on its own in commercial products - registered for the protection of cereals;
• propamocarb + cymoxanil — Ambora Duo (propamocarb hydrochloride), Axidor, Edegal Plus, Prosim, Rival Duo, Samiron,
• zoxamide + cymoxanil - Electis CX, Lieto 66 WG, Reboot 66 WG.

How the substances mentioned above work in the protection of individual plant parts, you will learn more: Potato blight remedies

Other remedies for potato blight

In general, in the current Polish register of plant protection products, there are 88 fungicides approved for potato protection against potato blight. In addition to the above-mentioned, we also have those containing:

• copper compounds (copper oxychloride and/or hydroxide or in the form of Bordeaux mixture);
• copper oxychloride + metalaxyl-M ;
• ametoctradin ;
• propamocarb hydrochloride ( propamocarb ) + fluopicolide ;
• bordeaux mixture + cymoxanil ;
• difenoconazole + madipropamide ;
• fluazinam + azoxystrobin ;
• fluazinam + valifenalate ;
• folpet .

Frequently Asked Questions (FAQ): Potato blight 2025 already in Polish fields!

What is potato blight?

Potato blight is a disease caused by the fungus Phytophthora infestans that attacks potato plants, leading to serious yield losses.

What are the symptoms of potato blight?

Symptoms of blight include small spots on the leaves that may be light green or brown. Over time, the spots turn brown, and a white, velvety coating appears on the underside of the leaves.

What conditions favor the development of potato blight?

Optimal conditions are air temperature from 3 to 29°C, and best in the range of 16–21°C, and humidity above 90%. Such conditions are conducive to the development of fungus.

How can I protect my plants from potato blight?

The best way to protect yourself is to use appropriate fungicides and regularly monitor your plantations to quickly respond to the first symptoms of the disease.

What fungicides are effective in the fight against potato blight?

Effective fungicides include amisulbrom, cyazofamid, and mandipropamid. It is important to use different preparations to prevent pathogen resistance.