How to Treat Late Blight on Potato?

Phytophthora infestans causes Late potato blight, quickly threatening potato production. The disease severely affects the crop, spreading rapidly, causing huge yield losses, and substantial monetary losses. Affected plants show black, water filled lesions on the leaves, stems and tubers which minimized the photosynthesis and affected the quality of the tubers. 

The economic losses increase due to additional expenses in controlling the disease and managing rotting tubers in storage.

Farmers can prevent and control late blight through these strategies: use resistant varieties, practice crop rotation, and ensure proper plant spacing. Apply fungicides and maintain field hygiene by removing infected plant parts. These measures assist in shielding potatoes from the impact of this blight at the later stage of its growth.

Late Blight Potato Symptoms

Late blight, caused by the pathogen Phytophthora infestans, manifests through several distinct symptoms on potato plants:

1. Leaf Lesions: The most common initial symptom is the appearance of dark, water-soaked lesions on leaves. These lesions typically start at the leaf edges or tips and expand rapidly under favorable conditions.
2. Stem Infections: Infected stems exhibit brown to black lesions, which can girdle the stem, causing the plant to collapse.
3. Tuber Rot: Infected tubers show firm, brownish-purple lesions on the skin, which can penetrate deep into the flesh, leading to a reddish-brown, granular rot. This can make the tubers unmarketable and susceptible to secondary infections.
4. White Mold: Under humid conditions, a white, fuzzy mold may appear on the underside of leaves and on infected tubers, indicating active sporulation of the pathogen.

What causes late blight on Potatoes:

Late blight is primarily caused by the oomycete pathogen Phytophthora infestans. The following factors contribute to the development and spread of this disease:

1. Cool, Wet Weather: Late blight thrives in cool (10-20°C) and wet conditions. Prolonged periods of leaf wetness from rain, dew, or irrigation are ideal for the pathogen to infect and spread.
2. Infected Seed Tubers: Planting infected seed tubers introduces the pathogen into the field. Infected tubers can carry the disease from one growing season to the next.
3. Volunteer Plants and Debris: Potato plants or tubers left in the field after harvest, known as volunteer plants, can harbor the pathogen and act as a source of infection for the next crop.
4. Spores Spread by Wind and Water: The pathogen produces sporangia and zoospores, which can be spread over long distances by wind and rain, leading to new infections.
5. Dense Planting: High plant density and poor air circulation create microclimates that are conducive to the development of late blight.

By understanding the symptoms and causes of late blight, farmers can implement effective management strategies to protect their potato crops from this destructive disease.

Difference Between Early and Late Blight of Potato

Causal Pathogens:

• Early Blight: Caused by the fungus Alternaria solani.
• Late Blight: Caused by the oomycete Phytophthora infestans.

Symptoms:

• Early Blight:
  • Leaves: Small, dark brown to black spots with concentric rings, creating a “target spot” appearance. Spots often appear on older leaves first.
  • Stems: Lesions can develop on stems, leading to girdling and plant collapse.
  • Tubers: Dark, sunken spots that may become leathery or corky.
• Late Blight:
  • Leaves: Large, dark, water-soaked lesions that rapidly expand, often starting at leaf edges or tips. Lesions can turn brown and dry out, with a white, fuzzy mold appearing on the underside of leaves under humid conditions.
  • Stems: Brown to black lesions that can girdle the stem, causing the plant to collapse.
  • Tubers: Firm, brownish-purple lesions on the skin that penetrate deep into the flesh, leading to a reddish-brown, granular rot. White mold may be present on the tuber surface in humid conditions.

How to prevent late blight of Potato

Various traditional fungicides control of late blight of potato blight effectively. Nevertheless, these fungicides may appear to be costly and are harmful when it comes to environmental aspects.

Apply Protectant Fungicides

These are called protectant fungicides and they cover the surface of the plant so that late blight fungus cannot invade it. However, they are at most, effective when used prior to fungal presence.

Apply Systemic Fungicides

These are taken up by the plant and are translocated in the tissues. They fight back late blight that is already on the plant.

Use Fungicide Alternation Program

A fungicide alternation program should be utilized to lower the chances of developing resistance to fungicide. It includes using various types of fungicides on rotation.

Consider Surfactants

Fungicides can be improved by surfactants that facilitate adhesion to the plant surface and penetration through the tissues. This can also render fungicides much more effective against late blight.

Novobac: A New Product for Late Blight of Potatoes

Late blight organic treatment

Our Innovative Product

The best fungicide for potato late blight- Novobac’s Cropium, which is for controlling the late blight of potato. These are the natural antifungal substances produced by Penicillium bilaiae, a bacteria used in making it. It is the best choice for the environment when we compare it with conventional fungicides. In addition, it is unlikely to develop fungicide resistance.

Additionally, Novobac offers another biological solution for controlling late blight: Streptomyces microflavus. It is based on a bacterium with proven antifungal properties that also help combat the pathogens responsible for late blight in potatoes. Both Streptomyces microflavus and Cropium are sustainable natural alternatives to chemical fungicides.

Active Ingredient

Cropium is a composition of Penicillium bilaiae, the active ingredient. Bacillomycin D and bilaiaene are among the antifungal compounds that this bacterium generates. These substances destroy the cell membrane of fungi which leads to their eventual death.

Cropium is better than conventional medical methods

For some reasons, Cropium can be preferred over conventional fungicides. It is more environmentally friendly and sustainable first. The environmental and health effects of using harsh chemicals in conventional fungicides are well-known. However, cropium is derived from natural products and is biodegradable.

First, Novobac’s organic fungicide is less likely to produce fungus resistance. It does so due to its different mode of action to that of conventional fungicides. Fungicides usually attack particular enzymes or protein found on fungi. Over the years, the fungi develop a resistance to these fungicides due to changing their genes. However, the best fungicide for potato late blight attacks the plasma membranes of fungi. This is a deeper process that is difficult to overcome.

How to Apply Cropium to Infected Parts of the Plant

It could be used to spray or soil drench infected potato plants. Mix it with water as instructed in the label while conducting foliar sprays. Spray the solution throughout the plant, including the leaves, stems, as well as the tubers. According to the labeled instructions, mix the fungicide with water for use as soil drenches. Apply it on the soil surrounding the plant base.

Here are some additional tips for applying Novobac:

• Apply cropium early in the morning or late in the evening when the temperature is cooler. This will help the cropium to adhere to the plant and be more effective.
• Avoid applying the best fungicide for potato late blight in windy conditions. This will help to prevent the cropium from being blown away.
• Apply it every 7-10 days, or more often if needed.
• If you are also using other pesticides, be sure to read the labels carefully to make sure that they are compatible with cropium.

Post-Harvest Management for late blight on potato

It is important for the late blight management in potato storage. Here are a few tips:

• Cure potatoes properly. Potatoes should be cured in a cool and dark location for 7-10 days. It will promote healing of wounds and suppress mushroom growth.
• Store potatoes at cool temps. They should be stored at a temperature between 40 and 50 degrees Fahrenheit. This will ensure that fungi do not grow.
• Maintain air circulation. Ensure that the ventilation in the storage area is adequate. It will also inhibit the development of fungi.
• Monitor storage conditions. Check the storage conditions frequently and remove any potatoes exhibiting late blight.

Conclusion

Potato late blight is a major disease which may result in large scale losses if not controlled. Nevertheless, it can be controlled by good prevention and treatment.Late blight potato can be prevented by using certified potato seeds, rotating crops, and using cropium as a preventative fungicide. Potato late blight fungus can be treated by removing infected plant parts, applying it, and avoiding overhead irrigation. Novobac’s fungicide is a sustainable and good fungicide that can help you to prevent late blight on your potato plants.

Cropium could assist you to safeguard your potato fields from late blight. Secondly, this fungicide can be used for the purpose of prevention of potato late blight fungus. Cropium should be applied to plants at the 6 inch stage so as to prevent late blight disease of potatoes.

The fungicide can be applied as a second agent for potato late blight infections. In case you locate potato late blight in your potato patch, use cropium to the infected plants to prevent the disease from spreading.

References:

1. Hatem, Amjad, et al. “Inhibition of the Growth and Development of Potato Early Blight Pathogen (Alternaria solani) by Combining Penicillium chrysogenum VKM F-4876D with Some Strobilurin-, Triazole-, and Phenylpyrrole-Based Fungicides.” Agriculture 12.9 (2022): 1488.
2. Sadravi, Mehdi, and MAHYA RAHIMIZADEH. “Ten Useful Penicillium Species.” University of Yasouj Plant Pathology Science 5.1 (2016): 1-13.