Petunia Diseases

Informational table showing disease name, symptoms, pathogen/cause, and management of Petunia diseases.
Petunia Diseases - Articles


Botrytis BlightFlowers have small translucent, or dead spots.Botrytis cinereaMaintain low relative humidity. Apply a fungicide to protect plants.
Phytophthora Crown RotBranches wilt and the plant rapidly dies as the crown. Young plants are quickly killed. Outdoors if the weather is dry, the stem at the soil line may have a dry rot.Phytophthora nicotianaeUse pasteurized potting mix or soilless mix known to be free of pathogens. Discards flats containing infected plants. Apply a fungicide to protect plants.
StuntYoung plants are stunted and thick.Lack of boronMaintain a soil pH below 7. Have a water test done to be certain calcium and sodium are not too high.
VirusSmall etches on the leaf are surrounded by a dark halo.Impatiens necrotic spot virus (INSV)Destroy infected plants. Take steps to control western flower thrips. Examine other plants in the greenhouse for INSV symptoms and destroy them.

Petal spotting caused by Botrytis

Prepared by Gary W. Moorman, Professor of Plant Pathology