Cranberry tip blight

The disease is caused by the fungus Monilinia oxycocci, which is a member of the Sclerotiniaceae family. It is a severe pathogen specifically targeting cranberry plants, causing two distinct phases of infection known as tip blight and fruit rot.

This fungus primarily affects cultivated species of cranberries. It is widely recognized in major cranberry-producing regions, often thriving in bogs and wetlands where high humidity levels are maintained throughout the growing season.

The first signs, known as tip blight, appear in early spring when succulent new shoots wilt, turn brown, and curl over, often covered in a grey mass of fungal spores. Later in the season, the fruit rot phase occurs, where berries become hard, light-colored, and shriveled as they become filled with fungal tissue.

Development and spread of the disease are heavily dependent on wet weather conditions. Ascospores released from overwintered mummified berries serve as the primary source of infection in the spring, which are then disseminated by wind and splashing rain to infect emerging green tissues.

The economic impact of this pathogen is significant for the cranberry industry. It can lead to severe losses in yield and fruit quality. If left unmanaged, the inoculum builds up in the soil, making it increasingly difficult to achieve healthy harvests in subsequent years.

• Remove and destroy mummified berries from the bog surface.
• Apply fungicides at the tight bud and bloom stages of development.
• Monitor the field regularly for early symptoms of wilting shoots.
• Improve water management to reduce surface humidity levels.
• Use certified healthy planting material to avoid introducing the fungus.