Problem area
Plant diseases
Diseases fall into three families — fungal, bacterial and viral — and they call for very different responses. Fungal problems are by far the most common and the most treatable. Telling them apart early decides whether you save the plant or pull it before it infects the rest.
Concentric brown rings (blight, leaf spot)Black spots with yellow halosWhite powdery coatingOrange or brown pustules (rust)Mottled, mosaic-patterned leaves (virus)Soft, smelly rot at the base