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Hydrangea Leaf Spot

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Caused By:-     Several fungi, but mainly Cercospora hydrangeae

Description

Corynespora cassiicola I think. There are many fungal leaf spot diseases of Hydrangeas. One very common one is caused by the fungus Cercospora hydrangeae others by Phyllosticta, and Colletotrichum fungi. All have similar signs and symptoms. This fungal leaf spot can affect most species of Hydrangeas and in general does not kill the plant, but makes it aesthetically unpleasing. Depending on the type of hydrangea, the leaf spot symptoms may vary. Spotting generally starts at the bottom of the plant on older leaves and works its way up the plant, because the fungus survives in infected fallen diseased leaves that remain on the ground. The spots are generally small, circular, and scattered across the leaf surface. They tend to have light brown centers with purple borders. Leaf spots can often be irregular or angular in shaped. Initial infection usually occurs during May, but symptoms don't become apparent until later in the season. As spots enlarge, they often become irregular or angular in shape. Often, heavily infected leaves turn yellow green and may fall to the ground. Once the fungi has been introduced to hydrangeas annual attack from these fungi is likely to occur. This is exacerbated by high rainfall and damp conditions due to splashes and as with all fungi they need a minimum wet time to germinate and infect.

Control

There are many fungal leaf spot diseases of Hydrangeas. One very common one is caused by the fungus Cercospora hydrangeae others by Phyllosticta, and Colletotrichum fungi. All have similar signs and symptoms.. This fungal leaf spot can affect most species of Hydrangeas and in general does not kill the plant, but makes it aesthetically unpleasing. Depending on the type of hydrangea, the leaf spot symptoms may vary. Spotting generally starts at the bottom of the plant on older leaves and works its' way up the plant, because the fungus survives in infected fallen diseased leaves that remain on the ground. The spots are generally small, circular, and scattered across the leaf surface. They tend to have light brown centers with purple borders. Leaf spots can often be irregular or angular in shaped. Initial infection usually occurs during May, but symptoms don't become apparent until later in the season. As spots enlarge, they often become irregular or angular in shape. Often, heavily infected leaves turn yellow green and may fall to the ground. Once the fungi has been introduced to hydrangeas annual attack from these fungi is likely to occur. This is exacerbated by high rainfall and damp conditions due to splashes and as with all fungi they need a minimum wet time to germinate and infect.

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