Powdery Mildew
Description: Fungus causing whitish spots on the underside of the leaves. Eventually the leaves shrivel and die. Thrives in high humidity.

Treatment: Spray with homemade all purpose cure described earlier.
 

Root Rot
Description: Fungus rots a plants roots.

Treatment: Cut away rotted root portions and spray with a fungicide.  

Early Blight
Description: Dark brown spots on leaves, stems and plant fruit seriously weakening the plant.

Treatment: Treat with harsh chemicals (maneb, zineb).  

Anthracnose
Description: Fungus caused by over watering where leaves become marked with dark smears and shrivel. Hardly ever occurs in hydroponics plants

Treatment: Spray with fungicide and remove damaged leaves.

Damping Off
Description: A fungus affecting small plants where stems meet soil causing them to fall over and die.

Treatment: Remove diseased sections. If it has affected a significant number of plants, replant in new soil and clean containers.  

Botrytis
Description: Grayish white, fuzzy leaf growth caused by inadequate ventilation. Not common in hydroponics gardens.
 
Treatment: Increase ventilation and remove affected leaves

Rust
Description: Slightly raised, powdery red pustules on the underside of the leaves causing them to turn yellow then brown and die. Helped along by high humidity. Very contagious.

Treatment: Apply harsh chemicals like zineb or maneb. 

Club Root
Description: Roots turn into a mass of club shaped tubers. Plants may become stunted.

Treatment: Dust with fungicide

Crown and Stem Rot
Description: Fungus causes plant to turn pulpy and rot.

Treatment: Cut away rotted plant portions and spray with a fungicide.