Potatoes rank among the most popular vegetables worldwide, playing a crucial role in global diets. In India, they are not only a dietary staple but also a significant cash crop that supports the livelihoods of countless farmers. From household kitchens to global fast-food chains, potatoes are in constant demand. However, potato farming isn’t without challenges—disease outbreaks can lead to reduced yield, poor quality, and results in major economic losses.

Early detection of diseases is critical for sustainable farming and for obtaining maximum yield. This blog offers a comprehensive potato health check by helping farmers recognize the symptoms of common diseases affecting potato crop and by making them understand how crop protection solutions and the right agrochemical suppliers can effectively mitigate these issues.

Common Diseases Affecting Potato Crop

1. Early Blight (Alternaria solani)

Early blight is one of the most common fungal diseases in potatoes. If not managed on time, it can cause up to 50% yield loss.

The disease primarily affects tubers and leaves. The symptoms at first appear as tiny (1-2 mm) round to oval brown patches on the older and lower leaves. These lesions possess the potential to become larger and more angular in the future. Mature lesions on leaves have a papery, dry appearance and frequently have bullseye-like, concentric rings.

The symptoms on the tuber include depressed, brown, round to irregular lesions with dry, corky, brown flesh below. During storage, lesions often get bigger, and the damaged tubers eventually wilt.

Control:

• Grow the crop with disease-free seed tubers.
• The crop needs to get balanced fertilizer dosages, particularly for nitrogen. Applying urea (1.0%) to the crop 45 days after sowing, followed by further sprayings eight to ten days after the first spray, helps the crop escape the intense attack of early-stage blight.
• Spraying Bordeaux mixture (1.0%) and copper oxychloride (0.30%) is advised for the management of early blight disease in hilly areas.
• Avoid growing solanaceous crops next to potato fields since they serve as collateral hosts for the disease-causing organisms.

Using Crop Protection solutions like protective fungicide sprays ensures early containment.

2. Late Blight (Phytophthora infestans)

All plant parts, including the leaves, stems, and tubers, are impacted by the disease.

Leaves: It starts as tiny, pale green dots on plants and grows into big, water-soaked lesions. Around the dead spots on the underside of the leaves, a ring of white mildew (cottony growth) develops. Water-soaked regions become necrotic brown in dry weather.

Stems: On stems, light brown elongated lesions grow that can encircle the stem.

Tubers: Reddish brown dry rot lesions develop in the tubers, ranging from superficial to deep. The infected tuber flesh turns “caramelized” and takes on a syrupy consistency. On the edges of the affected tissue, a metallic tinge often appears. The disease is spread in the following season by tubers that are the true carriers of the pathogen. While infected seed tubers can develop into healthy plants, the disease can infect the stem and lower leaves when conditions are favorable for its growth (10–12 degrees Celsius and relative humidity greater than 80%).

Control:

Seed potatoes should be carefully inspected before being stored. Any blighted tubers must be removed and buried deeply in the ground. Ridges should be raised to a level where all of the daughter tubers are covered in order to reduce the possibility of infection after exposure.

Irrigation should be stopped immediately if the weather (temperature 10–20 degrees C, relative humidity >80%) is conducive to the development of the disease. Only minor irrigation is provided if necessary. When the disease attacks 75% of the crop foliage, the haulms should be cut, taken out of the field, and buried deep.

Protective sprays containing a contact fungicide, such as Mancozeb (0.2%), are effective before the disease manifests. If required, follow-up sprays should be applied eight to ten days apart.

Agrochemical suppliers offer combination fungicides that are highly effective against late blight, ensuring both curative and protective action.

3. Bacterial Wilt or Brown Rot (Pseudomonas solanacearum)

Bacterial wilt, sometimes known as brown rot, is a devastating potato disease. It results in two types of losses:

(i) Early plant withering and death, which results in a complete loss of yield.

(ii) Tuber rotting during storage or transportation.

Initial symptoms include a small wilting of the top, which is quickly followed by complete wilting. In an advanced stage, the bacterial mass is observed to ooze out as a dull, white, slimy mass on the cut surface when the base of the infected plants’ stem is cut transversely and squeezed.

Two forms of symptoms in tubers are vascular rot and pitted lesions. Vascular rot causes the vascular tissues to resemble a water-soaked circle, which may eventually turn brown.

Control:

Infected seed tubers, especially those from a sick crop that appears healthy, play a significant role in the disease’s transmission and carryover. Therefore, it is best to plant disease-free seed tubers sourced from disease-free regions. Avoid splitting the tubers when planting because this can spread the disease to healthy tubers as well. Using fertilizer and stable bleaching powder (12 kg/ha) in planting furrows lowers the frequency of wilt by 80%.

Rotating crops for two to three years, including maize, finger millet, cereals, garlic, lupin, onion, and cabbage, can decrease the disease inoculum.

Bacterial wilt has no effective chemical cure, making prevention critical. Choosing Crop Protection solutions from trusted Agrochemical suppliers that protect plant health and improve soil conditioning can reduce its impact.

4. Common Scab (Streptomyces spp.)

Although the disease does not result in yield losses, it deforms the tubers, lowering their market value and increasing peeling losses.

The disease primarily affects potato tubers, resulting in any of the following symptoms: raised rough corky pustules, 3–4 mm deep pits encircled by hard corky tissues, irregularly circular or star-shaped corky lesions surrounding lenticels, and irregular concentric corky rings surrounding lenticels. Severe attacks can cause dark brown sores on the roots and stolon.

Control:

Due to the pathogen’s extended survival on seed tubers and in soils, control is challenging.

However, using seed tubers free of disease could reduce the incidence of disease. Organomercurial compounds (0.015% for 20 minutes) or boric acid (3% for 30 minutes) are applied to the seed tubers prior to planting, and they are allowed to dry in the shade. The same process is repeated before the tubers are stored.

Negative conditions for the disease’s growth are created when high moisture levels are maintained in the ridge for a few weeks, at least during the early stages of tuber formation. Rotating crops with wheat, peas, oats, barley, lupin, soybean, sorghum, and bajra prevents the spread of disease.

Natural soil conditioners and microbial solutions, available from the Top Agrochemical Companies In India, can suppress scab-causing bacteria.

5. Potato Leafroll Virus (PLV)

Depending on the age of infection, the Potato Leafroll Virus (PLRV) causes either the primary or secondary symptoms in plants.

The primary signs appear as the crop grows. Only the top young leaves exhibit these symptoms, which typically cause them to stand erect, roll, and become slightly pale.

PLRV secondary symptoms appear when plants are cultivated from contaminated seed tubers.

These effects are more noticeable in older leaves.

The distinctive features of infected plants are rolling lower leaves that turn yellow, brittle, and leathery in texture, as well as a pale, stunted, and erect look.

Control:

Virus-free seed potatoes are used to control the disease. Propagating virus-free seeds in regions devoid of aphids can help. Aphid vector populations are managed through the use of appropriate contact and systemic insecticides.

6. Black Scurf and Stem Canker (Rhizoctonia solani)

The disease mostly affects tubers, sprouts, stems, and stolons. The most typical sign of black scurf is irregular lumps that cling to the tuber surface and range in color from dark brown to black. These asymmetrical lumps are firmly attached to the tuber’s surface and are difficult to remove.

Other symptoms of the tuber include skin cracks, pitting, crater-like depressions, stem-end necrosis, and shape deformation. The disease frequently harms sprouts in storage and after planting in fields. Damaged sprouts reveal tissue discoloration. The severely contaminated sprouts cannot emerge from the soil, resulting in gappy germination.

When the sprouts grow infected, they eventually develop cankers, which cause the stem bases to girdle. The leaves of these affected plants curl upward and have a pinkish or reddish border.

Control:

A combination of enhanced cultural practices and tuber disinfection effectively reduces the incidence and severity of black scurf.

The best results are obtained by treating tubers with an organomercurial chemical and applying PCNB (30 kg/ha) to the soil. Such treated seeds typically produce tubers that are clear of black scurf.

To fully eradicate the disease, treated seeds must be used consistently for two to three crop seasons. Rotating crops with maize or “dhaincha” (Sesbania aegyptiaca) for green manure also prevents the accumulation of disease.

Role of Agrochemical Suppliers in Potato Disease Management

Partnering with reliable Agrochemical suppliers ensures that farmers get:

• Access to high-quality, lab-tested crop protection products.
• Timely technical support for disease identification and solution planning.
• Training on safe and effective pesticide usage.
• Updates on the latest innovations in agrochemicals and bioproducts.

Takeaway Tips for Farmers

✅ Scout fields regularly, especially during moist and cool weather.

✅ Do not ignore minor leaf spots—they can be early signs.

✅ Always source seeds and crop inputs from verified suppliers.

✅ Embrace natural crop protection methods for soil-friendly farming.

✅ Consult with experts from the Top Agrochemical Companies In India for disease diagnosis and treatment.

By staying alert and informed, farmers can effectively protect their crops and livelihoods. After all, healthy crops mean healthy profits in farming!

FAQs

1.What are the early signs of disease in potato plants that farmers should watch out for?

Early signs include yellowing or browning of leaves, dark spots or rings, curling foliage, wilting, and stunted growth. If you notice white mold on leaves or black lesions on stems and tubers, it’s a clear indication of possible disease infestation that needs prompt attention.

2. How can farmers prevent the spread of potato diseases in their fields?

Good farming practices such as crop rotation, proper spacing, and using certified disease-free seeds are essential. Regular monitoring and early detection go a long way in containing infections. When needed, farmers can consult reliable agrochemical suppliers for preventive treatments.

3. Which potato diseases are most common in India, and how are they typically treated?

The most common diseases include Late Blight, Early Blight, Black Scurf, and Bacterial Wilt. Treatment often involves removing affected plants, improving drainage, and using targeted fungicides or bactericides. It’s important to follow region-specific advice for effective control.

4. When should a farmer consider using agrochemical products to manage potato diseases?

Agrochemical products should be considered when traditional methods like crop hygiene and soil treatment aren’t enough. Timely intervention with expert-recommended solutions can prevent widespread damage. Trusted agrochemical suppliers can guide farmers on the right products and application techniques.