Potatoes belong to the solanacea family. Potatoes are basically cool season crop which prefer cool weather. It is grown in both hills and plains.
In general, it is sown as a zaid crop in the hills region and a rabi crop in the plain region .
Potatoes are predominantly cultivated as rainfed crops in regions that receive an annual rainfall ranging from 1200 to 2000 mm. They are more prone to diseases in the cool winter and Rainy season, as they couldn’t withstand water stress.
Leaf blight of potato
Late blight affects leaves, stems and tubers of the plant. Initially the symptoms show water-soaked lesions on the leaves, as the disease proceeds these spots increase in size to form purple to brown colour and later turn black. On undersides of the leaves develops white powdery growth.
It often occurs at the petioles, rachis and stems causing them to break and the entire plant to fall over. The late blight also affects the tubers in which purplish brown spots/lesions, when the tuber is cut and turns later to rusty brown necrosis spreading from surface to centre of the tuber.
Management of late blight
Spray Fluopicolide 5.56% + Propamocarb hydrochloride 55.6% SC @ 2 ml/ltr water, or Dimethomorph 50% WP @ 2 gm/ltr Water.
Early Blight of Potato
The early blight typically starts on the lower leaves and slowly moves up the plant. The initial symptoms appear on the leaves, stem and tubers. It causes brown-black necrotic spots on leaves, which have a distinctive oval shape with concentric rings.
These spots can merge and spread across the entire leaves and other parts of the plant. The late blight also affects tuber’s surface and may show concentric rings and become leathery, sometimes covered in a velvety layer of black spores.
Management of Early blight
Spray Azoxystrobin 23%SC @ 1.25 ml/ltr Water or Chlorothalonil 75% WP @ 2 gm/ltr Water.
Bacterial soft rot
There are two stages of infection called black leg and soft rot. In the black leg stage, black lesions form at the base of the plant, tubers and other parts of plants. The tubers that are infected show systemic browning. The affected plants appear yellow in color. Eventually, the plants wither and die. The tubers rot and collapse. Infected tubers develop a soft, reddish, or black ring.
Management of Bacterial soft rot
Spray Kasugamycin 5% + Copper oxy chloride 45% WP @ 2 gm/ltr Water or Streptomycin sulphate 90% + Tetracycline hydrochloride 10% SP @ 6gm/30 ltr Water.
Common scab or corky scab
The main symptom is corkiness of the tuber’s outer layer. The infected tuber surface shows a russette appearance of about 1/4 inch deep. The infected tuber shows a slightly pitted texture with light brown to dark brown lesions. The affected tissue of the tuber tends to attract insects.
Management of Common scab / corky scab
Spray Thiophanate Methyl 70% WP @ 2 gm/ltr Water or Azoxystrobin 11% + Tebuconazole 18.3% w/w SC @ 1.5-2 ml/ltr Water.
