News Excerpt:

Several farmers of Sanaur in Patiala district have claimed that their tomato and potato crops have been damaged by blight disease, triggered by bad weather and fog.

About Late Blight Disease:

• Late blight, a fungal disease of potato and tomato plants that is caused by the water mold Phytophthora infestans.

• Symptoms: 

• • The first symptoms of late blight appear as small, light to dark green, circular to irregular-shaped water-soaked spots. 
  • During cool, moist weather, these lesions expand rapidly into large, dark brown or black lesions, often appearing greasy. 
  • A pale green-to-yellow border often surrounds the lesions.  
  • When plants have become infected, lesions (round or irregularly shaped areas that range in colour from dark green to purplish black and resemble frost injury) appear on the leaves, petioles, and stems. 
  • A whitish growth of spore-producing structures may appear at the margin of the lesions on the underleaf surfaces.
• The disease occurs in humid regions with temperatures ranging between 4 and 29 °C (40 and 80 °F). 
• Hot dry weather checks its spread. Potato or tomato plants that are infected may rot within two weeks.
  • The Great Famine in Ireland in the mid-19th century was caused by late blight of the potato plant.

Prevention of Disease:

• The disease can be managed with a timely application of fungicide, though epidemics can occur rapidly once crops are infected.
• Maintaining proper spacing between plants within the canopy was another key aspect.
• Adequate spacing promotes better aeration and helps mitigate the risk of late blight development.
• The prompt destruction of infected crop residue to prevent the spread of the disease to nearby fields. 
• The use of drip irrigation where feasible and emphasised daytime irrigation so that foliage dries before nightfall and the risk of disease proliferation is minimised.