Early Blight and Late Blight

Early Blight of Potato:-

Pathogen:- Alternaria solani

Symptoms:-

> It is present in both hills & plains.

> Brown-black necrotic spot-angular, oval shape characterized by concentric rings.

> Several spot coalesce & spread all over the leaf.

> Shot holes on fruits.

Management:-

> Disease free seed tubers should be used for planting.

> Removal and destruction of infected plant debris should be done because the spores lying in the soil are the primary source of infection.

> Very early spraying with Zineb or captan 0.2% and repeating it for every 15 – 20 days gives effective control.

> The variety Kufri Sindhuri possesses a fair degree of resistance.

Late Blight of Potato:-

Pathogen:- Phytopthora infestans

Symptoms:-

> It affects leaves, stems and tubers.

> Water soaked spots appear on leaves, increase in size, turn purple brown& finally black colour

> White growth develops on under surface of leaves.

> This spreads to petioles, rachis& stems.

> It frequently develops at nodes.

> Stem breaks at these points and the plant topples over. In tubers, purplish brown spots and spread to the entire surface on cutting, the affected tuber show rusty brown necrosis spreading from surface to the center.

Management:-

> Protective spraying with mancozeb or zineb 0.2 % should be done to prevent infection of tubers.

> Tuber contamination is minimized if injuries are avoided at harvest time and storing of visibly infected tubers before storage.

> The resistant varities recommended for cultivation are Kufri Naveen, Kufri Jeevan, Kufri Alenkar, Kufri Khasi Garo and Kufri Moti.

> Destruction of the foliage few days before harvest is beneficial and this is accomplished by spraying with suitable herbicide.