Diaporthe serafiniae

Systematic position and nature of the pathogen: Diaporthe serafiniae belongs to the kingdom Fungi, phylum Ascomycota, and genus Diaporthe. It is a highly specialized phytopathogenic fungus known to be one of the agents causing diaporthe or phomopsis-like diseases, which affect a wide range of herbaceous host plants.

Diseases and host crops: The primary crop on which this species is most actively identified is the sunflower. The pathogen causes stem necrosis, head rot, and premature wilting of plants. The infection leads to a significant reduction in seed filling and compromises seed quality, posing a serious threat to large-scale oilseed production.

Biology and life cycle: The life cycle of the fungus includes both sexual (perithecia) and asexual (pycnidia) stages. The spread of the infection occurs mainly via ascospores, which are dispersed by wind and rain splashes. Primary infection usually starts on the lower leaves, from where the mycelium gradually penetrates the stem, destroying the plant's vascular system and hindering nutrient supply to the seed head.

Conditions for development and harmfulness: Optimal conditions for the massive development of Diaporthe serafiniae include high atmospheric humidity, frequent rainfall, and moderate temperatures (between +20…+25°C). The economic impact manifests as crop lodging, yield losses of up to 30–50%, and potential toxin accumulation, which degrades the quality of oil and meal products.

Protection and control measures: Managing this pathogen requires an integrated strategy, including:

• Utilizing sunflower hybrids with genetic resistance to diaporthe species.
• Maintaining crop rotation with a minimum interval of 4–5 years for susceptible hosts.
• Rigorous destruction of crop residues where the fungus persists as mycelium and fruiting bodies.
• Application of systemic fungicides during early vegetative stages (4–6 leaf pair phase) to prevent primary infection.