Blueberry mummy berry

The fungus Monilinia vaccinii-corymbosi is the causative agent of mummy berry, a devastating disease that specifically targets highbush blueberries and related Vaccinium species. This pathogen is known for its two-phase life cycle that causes significant damage to both the vegetative tissues and the developing fruit of the plant.

The disease cycle begins with the primary phase, where emerging shoots and leaves show signs of sudden wilting and browning, appearing as if scorched by frost. The secondary phase occurs during fruit maturation, resulting in the transformation of berries into hard, shriveled, tan-colored "mummies" covered in masses of conidial spores.

Environmental conditions are critical for disease development, specifically cool, wet weather during the spring bud-break stage. High humidity facilitates the germination of fungal apothecia originating from overwintered mummies on the ground, allowing wind and water to spread spores to healthy blueberry tissues.

The economic impact of this disease is severe, often resulting in heavy crop losses if left unmanaged. Beyond the direct loss of fruit, the disease limits the marketability of the remaining yield and can weaken the overall health and vigor of the blueberry bushes over several growing seasons.

Effective management requires an integrated strategy, focusing on breaking the disease cycle. Burying or covering overwintered mummies with thick layers of mulch prevents spore release, while timely applications of systemic fungicides during the early spring bloom stage are essential to suppress infection and protect the crop.

• Applying 2-3 inches of mulch to cover overwintered inoculum
• Removing infected branches as soon as symptoms appear
• Scheduling fungicide sprays based on weather monitoring
• Selecting cultivars with higher natural resistance to fungal pathogens