Stamen blight

Stamen blight is a specific fungal disease caused by the pathogen Hapalosphaeria deformans. This fungus specializes in attacking the reproductive parts of plants, interfering with their development and reproductive success.

The primary host for this pathogen is the common red raspberry. The fungus invades the floral parts, specifically targeting the stamens and pistils, which results in significant physiological stress to the plant's reproductive organs.

Symptoms become apparent during the flowering stage, characterized by distorted, hypertrophied stamens that often appear abnormal or discolored. The presence of the fungus prevents successful pollination, leading to the development of malformed, crumbly, or otherwise unmarketable berries.

Development and spread of the disease are highly dependent on environmental conditions, particularly high humidity and wet weather during the bloom period. The fungal spores are easily dispersed by wind, rain splashes, and pollinating insects, allowing the disease to spread rapidly within a raspberry patch.

The damage caused by stamen blight results in yield loss and a decrease in fruit quality. Because the infection impairs fertilization, the resulting fruits are often underdeveloped or show significant structural defects, making them unsuitable for commercial sale or fresh consumption.

• Use certified disease-free planting stock.
• Maintain proper spacing to ensure adequate airflow.
• Prune and destroy infected canes or flowers.
• Apply preventative fungicides before the onset of flowering.

Integrated pest management is crucial for control. By combining cultural practices, such as sanitation and canopy management, with targeted chemical interventions, growers can effectively mitigate the impact of the disease on their raspberry plantations.