Articles

Petunia Diseases

Name: Petunia Diseases
SKU: ART-3536

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

Updated:

July 7, 2025

Purple petunia flowers

Disease	Symptoms	Pathogen/Cause	Management
Botrytis Blight	Flowers have small translucent or dead spots.	Botrytis cinerea	Maintain low relative humidity. Apply a fungicide to protect plants.
Phytophthora Crown Rot	Branches 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 nicotianae	Use pasteurized potting mix or soilless mix known to be free of pathogens. Discards flats containing infected plants. Apply a fungicide to protect plants.
Stunt	Young plants are stunted and thick.	Lack of boron	Maintain a soil pH below 7. Have a water test done to be certain that calcium and sodium are not too high.
Virus	Small 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.