Botryosporium blight

The causal agent of this plant disease is the fungus Botryosporium pulchrum. It is primarily considered an opportunistic pathogen or a saprotroph that thrives on decaying organic matter but can rapidly colonize living plant tissues if they are stressed, wounded, or maintained under improper environmental conditions.

This pathogen affects a variety of greenhouse crops, including tomatoes, cucumbers, peppers, and various ornamental species. It frequently targets plants that are in a stage of high physiological activity or those that have recently undergone pruning, as the wounds provide easy access points for fungal colonization.

The primary symptom of a Botryosporium infection is the emergence of a conspicuous, white, fuzzy growth on the affected plant surfaces, such as stems, petioles, or leaves. As the infection progresses, the underlying tissue becomes necrotic, turns dark, and develops a soft, wet rot, eventually leading to the collapse of the plant part.

Development and spread of the fungus are strictly linked to high relative humidity, typically exceeding 85%, and poor air circulation within the greenhouse environment. These conditions allow the spores to germinate quickly and colonize new tissue, often causing a rapid epidemic within a single season if humidity levels are not managed.

The economic impact of the disease stems from the loss of fruit or foliage quality and the potential for total plant death. Effective management is essential to prevent the spread of the pathogen, which relies heavily on eliminating humidity hotspots and strictly adhering to sanitation protocols in the greenhouse facility.

• Improving ventilation to reduce relative humidity.
• Removing all diseased plant debris and maintaining strict sanitation.
• Avoiding high-density planting to increase air flow.
• Applying recommended fungicides at the first sign of visible spores.