Ascochyta blight

Ascochyta blight, caused by the fungus Ascochyta hortorum, is a destructive plant disease affecting various vegetable crops. This pathogen specializes in attacking stems, foliage, and fruits, often leading to rapid tissue necrosis and significant economic losses.

The host range of Ascochyta hortorum includes major crops such as tomatoes, cucumbers, and other solanaceous or cucurbit plants. It is particularly problematic in humid greenhouse environments where high density and moisture facilitate rapid spread and development of the fungal spores.

Symptoms typically manifest as necrotic lesions that appear as spots with a distinct margin. As the disease progresses, small black fruiting bodies called pycnidia become visible within the lesions. These structures are essential for the survival and multiplication of the fungus throughout the growing season.

The development of the disease is heavily influenced by environmental factors, particularly high humidity and temperatures between 20°C and 25°C. Rain splashes and irrigation water play a major role in the spread of spores from infected plant debris to healthy plant tissues.

Effective management of Ascochyta blight requires an integrated pest management approach. Key measures to control the spread and impact include:

• Strict sanitation by removing and destroying all infected plant materials.
• Crop rotation to prevent the buildup of soil-borne inoculum.
• Improving ventilation and moisture control within greenhouses.
• Applying preventive and curative fungicides registered for use against Ascochyta species.