Botryosporium blight

Botryosporium blight is a fungal infection caused by members of the Botryosporium genus, most notably Botryosporium pulchrum. This fungus acts primarily as a facultative parasite that thrives on senescing, damaged, or weakened plant tissues, often causing secondary rot that spreads rapidly throughout a greenhouse environment.

The disease frequently affects a variety of solanaceous crops, including tomatoes and peppers, as well as cucumbers. It is predominantly observed in high-humidity enclosed environments such as greenhouses and polytunnels. By compromising the health of the leaves and stems, the pathogen directly impacts the photosynthetic efficiency and overall vigor of the host plant.

The primary symptom of this infection is the appearance of a conspicuous white to greyish-white mold growth on the surface of leaves or stems. This mold is composed of densely branched conidiophores, which give the affected area a distinctive fuzzy texture. As the infection progresses, the underlying tissue darkens, becomes necrotic, and eventually collapses into a soft, mushy rot.

Favorable conditions for the development of Botryosporium include high relative humidity (above 85%) and poor air circulation. The fungus colonizes plant surfaces effectively when moisture is trapped for extended periods. Temperature levels typical of greenhouse cultivation, generally ranging from 20°C to 25°C, create an ideal environment for the pathogen to propagate and release airborne spores.

• Improving ventilation and lowering humidity levels within the growing area.
• Promptly removing and disposing of any infected plant material to reduce inoculum load.
• Maintaining proper plant spacing to allow adequate light and airflow.
• Applying recommended fungicides as part of an integrated pest management strategy.
• Implementing strict sanitation protocols for tools, equipment, and greenhouse structures.