Rudbeckia (black eyed susan) Perennial Shrub Diseases:


Aster Yellows:

Symptoms-Leaf-like structures form where flower parts should be located. Plants may branch abnormally heavily (witches’ broom), leaves may be yellow and plants may be stunted.

Management-Remove and destroy infected plants. Control leafhoppers early in the season with insecticides in order to suppress spread of the pathogen from weeks to your plants.

Bacterial Leaf Spots:

Symptoms-Angular, brown to purplish spots primarily on lower leaves may kill the entire leaf.

Management-At the end of the season, remove all above ground plant parts. Avoid using sprinkler irrigation.


Downy Mildew:

Symptoms-Dark, blotchy areas on upper leaf surfaces and grayish white fuzzy growth on leaf undersides.

Management-Provide good air circulation around the plants. Apply PureSpray Green to help control and prevent mildew.

Fungal Leaf Spots:

Symptoms-Brown spots on lower leaves spread upward during wet weather or when sprinkler irrigation is used.

Management-Start with healthy plants and do not purchase any with spots on leaves. Remove infected leaves and provide good air circulation around the plants. Avoid using sprinkler irrigation. Apply PureSpray Green to help control and prevent leaf spot.

Powdery Mildew:

Symptoms-White fungal growth on leaves causes them to yellow, die and fall prematurely.

Management-Apply PureSpray Green. An all organic spray that works great for controlling powdery mildew. BUY NOW


Symptoms-Dusty, rusty red spores form in blister-like spots on leaves and stems.

Management-Some Carex species (sedges) act as alternate hosts of Uromyces and Puccinia.

Septoria Leaf Spot:

Symptoms-Dark brown to purplish spots 1/8″ to inch in diameter may be rounded or angular in shape starting on the lower leaves and spreading upward when the weather is wet or when sprinkler irrigation is used.

Management-Start with healthy plants and do not purchase ones with spots on the leaves. Apply PureSpray Green to help control and prevent leaf spot.

Stem Rot:

Symptoms-Lower leaves yellow, wilt, and die. The entire plant may die. White, cottony fungal growth forms at the soil line; Small, white to reddish brown balls or black, long (mouse dropping-sized) structures form on the white growth.

Management-Remove and destroy infected plants and even remove and replace the topsoil immediately around the plant. Do not attempt to compost the dead plant material.

Verticillum Wilt:

Symptoms-Leaves yellow, brown, and wilt.

Management-Diseased plants should be removed and destroyed. Verticillium survives in soil for many years in soil.


Symptoms-Light and dark green mosaic coloration forms on the leaves. Leaves may be distorted and the plants stunted.

Management-Obtain a diagnosis from a plant disease clinic to confirm the identity of the virus present. Remove and destroy infected plants.

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