Phomopsis

Phomopsis

Phomopsis spores under a microscope

Phomopsis is a genus of fungi in the family Diaporthaceae. It is known for causing diseases in a wide range of plants, including fruit trees, grapevines, and ornamental plants. The genus is characterized by its production of pycnidia, which are asexual fruiting bodies that release conidia (asexual spores).

Taxonomy

Phomopsis is classified within the Ascomycota division, which is one of the largest divisions of fungi. It belongs to the class Sordariomycetes, order Diaporthales, and family Diaporthaceae. The genus was first described by the Italian mycologist Pier Andrea Saccardo in 1884.

Morphology

Phomopsis species produce pycnidia, which are flask-shaped structures that contain conidia. These conidia are typically hyaline (transparent) and vary in shape from oval to cylindrical. The pycnidia are often embedded in the host tissue, making them difficult to detect without microscopic examination.

Life Cycle

The life cycle of Phomopsis involves both sexual and asexual reproduction. The asexual stage is the most commonly observed and involves the production of conidia within pycnidia. These conidia are dispersed by wind, rain, or insects and infect new host plants. The sexual stage, which is less frequently observed, involves the production of ascospores within perithecia.

Pathogenicity

Phomopsis species are known to cause a variety of plant diseases, including Phomopsis blight, canker, and fruit rot. These diseases can lead to significant economic losses in agriculture and horticulture. The symptoms of Phomopsis infections vary depending on the host plant and environmental conditions but often include leaf spots, stem lesions, and fruit decay.

Control and Management

Phomopsis infection on grapevine

Managing Phomopsis diseases involves a combination of cultural practices, chemical treatments, and resistant plant varieties. Cultural practices include removing and destroying infected plant material, improving air circulation, and avoiding overhead irrigation. Chemical treatments may involve the use of fungicides, although resistance can develop over time. Breeding and planting resistant varieties is a long-term strategy for managing Phomopsis diseases.

Related Pages

• Fungal plant pathogens
• Ascomycota
• Plant disease management