Gymnosporangium globosum

Gymnosporangium globosum is a species of fungus in the family Pucciniaceae. It is a plant pathogen that primarily affects members of the juniper family.

Description

The Gymnosporangium globosum fungus is characterized by its unique life cycle, which involves two different host plants. The fungus spends part of its life cycle on junipers, where it produces orange, gelatinous teliospores during wet weather. These spores are then carried by the wind to the secondary host, typically an apple or pear tree, where they germinate and infect the tree, causing a disease known as cedar-apple rust.

Life Cycle

The life cycle of Gymnosporangium globosum is complex and involves two different host plants. The fungus overwinters on junipers as a hard, brownish gall. In the spring, during wet weather, these galls swell and produce orange, gelatinous teliospores. These spores are then carried by the wind to the secondary host, typically an apple or pear tree. Once on the secondary host, the spores germinate and infect the tree, causing a disease known as cedar-apple rust. The fungus then produces aeciospores, which are carried by the wind back to a juniper, completing the life cycle.

Impact

Gymnosporangium globosum is a significant pathogen of both junipers and apple or pear trees. The disease it causes, cedar-apple rust, can result in significant yield losses for apple and pear growers. In addition, the disease can weaken and eventually kill junipers.

Control

Control of Gymnosporangium globosum involves a combination of cultural practices and chemical treatments. Cultural practices include planting resistant varieties of apples and pears, and removing and destroying infected junipers. Chemical treatments include the application of fungicides to both the junipers and the apple or pear trees.

See Also

• Cedar-apple rust
• Juniperus
• Pucciniaceae
• Plant Pathology