Vegetable Diseases

Reasons why the leaves of vegetable seedlings curl

White rot is a destructive disease of onions and garlic.

Specific virus diseases are difficult to distinguish and produce a wide range of symptoms including stunted, slow-growing plants, twisted, crinkled, cupped, or deformed leaves, and leaf discoloration (yellow mottling and mosaic patterns, ringspots, and dark-green banding).

Symptoms of verticillium include older leaves turning yellow, dying, and dropping off infected plants.

Many bacteria, fungi, and viruses can cause blights. Southern blight is caused by the fungus Sclerotium rolfsii. Most blights are favored by certain weather conditions, such as hot and humid or cool and moist.

Septoria leaf spot starts on lower leaves of tomatoes as small, circular gray lesions (spots) with dark borders.

Powdery mildew is a common fungal disease that grows as a white powdery coating over the surfaces of leaves. It has a wide host range.

Sweet potatoes that develop dark spots on their skin surface may be infected with a fungal disease called scurf.