Phoma inflorescence blight

The causative agent of this disease is the fungus Plenodomus influorescens, an ascomycete pathogen specifically known for infecting the reproductive stages of host plants. This pathogen is increasingly recognized as a significant threat to agriculture, particularly within the Brassicaceae family.

The disease primarily targets crops such as oilseed rape (canola), mustard, and various other cruciferous species. The infection cycle is synchronized with the flowering stage, causing severe disruption to the plant's reproductive system and subsequent seed set development.

Symptoms typically present as chlorotic and subsequently necrotic lesions on buds, petals, and floral stalks. As the fungus colonizes the tissues, affected areas show darkening and structural degradation. Under humid conditions, pycnidia (small, black, fruiting bodies) emerge on the necrotic tissue, releasing spores for further infection cycles.

Environmental conditions favoring the development and spread of Plenodomus influorescens include high relative humidity, frequent rainfall, and mild temperatures during the flowering window. These conditions promote the germination of spores and the secondary spread of the pathogen throughout the field.

The impact of this disease on crop productivity is severe. Inflorescence blight prevents proper fertilization and leads to a reduction in pod numbers and seed weight. Yield losses are significant, as the pathogen directly interferes with the formation of the harvestable part of the plant.

• Implement strict crop rotation (at least 3 years without Brassica hosts).
• Use resistant or tolerant cultivars when available.
• Ensure deep tillage to bury infected stubble and reduce primary inoculum.
• Monitor fields during flowering and apply fungicides if conditions favor disease outbreaks.