Nectria galligena

Nectria galligena is a species of fungus in the family Nectriaceae. It is commonly known as the European canker fungus, and is a significant pathogen of a variety of tree species, particularly apple trees.

Description

Nectria galligena is characterized by its small, red, cushion-like fruiting bodies known as perithecia. These structures produce ascospores, which are the primary means of reproduction for the fungus. The fungus also produces asexual spores known as conidia in structures called pycnidia.

Life Cycle

The life cycle of Nectria galligena involves both sexual and asexual reproduction. The fungus overwinters as mycelium or as perithecia on the bark of infected trees. In the spring, the perithecia release ascospores, which are spread by wind and rain to potential host trees. If conditions are favorable, the ascospores germinate and infect the host through wounds in the bark. The fungus then grows and spreads within the host, causing cankers and other symptoms of disease. In the late summer and fall, the fungus produces pycnidia, which release conidia that can infect other trees.

Disease Symptoms and Management

Nectria galligena causes a disease known as European canker, which is characterized by the formation of cankers on the branches and trunks of infected trees. The cankers are initially small and sunken, but can grow larger and cause significant damage over time. Infected trees may also exhibit wilting, yellowing of leaves, and premature leaf drop.

Management of European canker involves a combination of cultural practices and chemical control. Cultural practices include regular pruning to remove infected branches, and avoiding injury to the tree bark which can provide entry points for the fungus. Chemical control involves the application of fungicides to protect healthy trees and prevent the spread of the disease.

Economic Impact

Nectria galligena is a significant pathogen of apple trees, and can cause substantial economic losses in apple orchards. The fungus can also infect other fruit trees, as well as ornamental trees and shrubs.

See Also

• List of apple diseases
• Fungal plant pathogens and diseases

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