Question

Classify plant diseases depending upon their occurrence and transmission.

Answer 1

Depending upon the occurrence and transmission, plant diseases are classified into four categories:

1. Seed-borne diseases: These diseases spread through seeds, e.g., “ergot of bajra” or of pearl millet; “leaf spot of rice”; “loose smut of wheat”; red rot of sugarcane; — all are caused by fungi.
2. Soil-borne diseases: These diseases spread through the soil and mostly affect roots and stems of crop plants, e.g., “smut of bajra,” “tikka disease of groundnut”.
3. Air-borne diseases: These crop diseases are transmitted by the air, e.g., “rust of wheat”, “blast of rice”, etc. Air-borne diseases attack all aerial parts of the plants, e.g., leaf, flower, and fruits.
4. Water-borne diseases: Pathogens of these crop diseases are transmitted by the water, e.g., “bacterial blight of rice”.