Marssonina coronaria

Marssonina coronaria is a fungal pathogen that causes Marssonina blotch, a common disease in apple trees. It is named after the Swiss botanist Robert Chodat, who first described the species in the late 19th century.

Taxonomy

The fungus belongs to the Ascomycota division, the largest division of fungi, which includes more than 64,000 species. It is part of the Dermateaceae family, a group of fungi that are known for their plant pathogenic properties.

Description

Marssonina coronaria is characterized by its dark brown to black fruiting body, which produces spores that are spread by wind and rain. The spores germinate on the surface of the apple leaves, causing brown spots that eventually lead to leaf fall.

Disease Cycle

The disease cycle of Marssonina coronaria begins in the spring when the fungus produces spores that are spread by wind and rain to apple leaves. The spores germinate and penetrate the leaf surface, causing brown spots. As the disease progresses, the spots coalesce and the leaves fall prematurely. The fungus overwinters in fallen leaves and produces new spores the following spring.

Management

Management of Marssonina blotch involves a combination of cultural practices and chemical control. Cultural practices include pruning and sanitation to reduce the amount of inoculum. Chemical control involves the use of fungicides to protect the leaves from infection.

Impact

Marssonina blotch can cause significant yield loss in apple orchards. In addition to reducing the number of apples, the disease also affects the quality of the fruit, making it less marketable.

See Also

• Apple scab
• Cedar-apple rust
• Fire blight