Mycosphaerella horii

Mycosphaerella horii is a species of fungus in the family Mycosphaerellaceae. It is a plant pathogen that primarily affects apple trees, causing a disease known as Apple blotch.

Taxonomy

The species was first described in 1951 by Japanese mycologist Yoshiyuki Horii, after whom it is named. It belongs to the genus Mycosphaerella, which comprises over 3000 species of fungi.

Description

Mycosphaerella horii is a ascomycete fungus, meaning it reproduces sexually through the formation of ascospores. The fungus forms small, black, spherical fruiting bodies known as pseudothecia on the surface of infected leaves.

Pathology

Mycosphaerella horii is the causal agent of Apple blotch, a disease that causes significant damage to apple crops worldwide. The fungus infects the leaves of apple trees, causing dark, irregularly shaped blotches. These blotches can coalesce, leading to extensive leaf damage and premature leaf drop. This can result in reduced fruit yield and quality.

Management

Control of Mycosphaerella horii and Apple blotch disease involves a combination of cultural practices and chemical treatments. Cultural practices include pruning and removal of infected leaves to reduce the source of inoculum. Chemical treatments typically involve the use of fungicides.

See also

• List of Mycosphaerella species
• Apple scab
• Plant pathology