Not many plant diseases have left a profound mark on human history as the late blight of potatoes. A deadly plant disease that is caused by the destructive oomycete Phytophthora infestans. This pathogen thrives in cool, moist conditions. The disease is famously known to have been responsible for the Irish Potato Famine of the 1840s, which claimed around a million lives. Even in the 21st century, late blight continues to threaten global potato production. Early detection of the disease and the use of disease-resistant varieties are especially important in the fight against this disease
What causes late blight in Potatoes?
Late blight disease may have its origin in the seeds or tubers. It is caused by the fungus like Phytophthora infestans. That is why late blight is also known as Phytophthora infestans.
Phytophthora infestans, a fungus that causes late blight thrives during warm temperatures from 8-15°C with high levels of precipitation.
The disease develops from infected seed or in some instances, direct germination from the resting oospores in the soil
What are the Symptoms of late blight?
There are many symptoms of early blight. Some are very common others you really need to pay attention. The following are some of the symptoms early blight in potatoes.
- Small, circular or irregular-shaped water-soaked spots which are green in color. This symptoms starts to appear first at the tip of the leaves or edges. This is because these are areas where dew is retailed the longest.
- After few days without treatment, the lesions turns to Dark brown or black. These lesions would be surrounded by yellow chlorotic halo.
- Entire leaves can become blighted and killed within just a few days.
- white mildew on the edge of the lesions
- A pale green border (sometimes yellow) surrounds the lesions
- Red-brown rot under the skin of the potato. The rot increases with the time and degree of infestation.
Related: Early Blight of Tomatoes
Prevention Measures
The following measures will prove helpful for any organic gardener who does not want to loose her crop.
- Use disease-free potato seeds
- Make sure to destroy any volunteer plants and some weeds like nightshade.
- Avoid overhead watering practices especially at night
- Make sure to rotate your crops as necessary.
- Feed your soil enough for a strong crop to avoid it from infestation.
- Try to Choose and plant resistant varieties.
- Apply lactobacillius, baking soda or any organic fungicide for protective strategies.
- Destroy infected plants as soon as you discover the disease.
- Remove volunteer potatoes as they can be used to spread the disease.
- Earthing up your potatoes helps to provide protection to the tubers from the late blight spores washed down from the leaves.
Conclusion
In conclusion, late blight of potatoes remains the most destructive plant disease, which threatens food security and farmers’ livelihoods around the globe. Late blight spreads very fast under cool and moist conditions. Effective control relies on an intentional prevention approach that includes the use of resistant potato varieties, proper field sanitation, timely use of organic fungicide, and regular crop monitoring. By understanding the disease and adopting proactive management strategies, organic farmers can significantly reduce losses and ensure healthy and sustainable potato production.