Bladnekroser

Bladnekroser, or leaf necrosis, is a general plant pathology term used to describe tissue death in leaves, presenting as brown to black patches with irregular margins. The necrotic areas reduce the photosynthetic area of the leaf and can lead to premature leaf drop and overall plant decline, depending on the severity and the plant’s vigor.

Causes of bladnekroser are diverse and can be biotic or abiotic. Biotic causes include fungal pathogens such as Cercospora, Septoria, Alternaria, Phyllosticta, and various Botryosphaeriaceae species; bacterial infections like Xanthomonas and Pseudomonas that cause leaf spots; oomycetes such as Phytophthora; and viral infections that cause diffuse or localized necrosis. Abiotic causes include drought, heat or cold stress, excessive light, nutrient imbalances (notably deficiencies or toxicities of potassium, iron, or magnesium), waterlogging, salinity, herbicide injury, and physical damage from tools or weather.

Symptoms and diagnosis rely on lesion appearance, distribution on the plant, and the environmental context. Diagnosis may involve laboratory tests to identify specific pathogens (microscopy, culturing, PCR, or serology) and an assessment to rule out abiotic stress. Because bladnekroser is a symptom shared by many conditions, accurate identification of the underlying cause is essential for effective management.

Management and prevention focus on the underlying cause. For biotic conditions, practices include using resistant varieties, crop rotation, sanitation, removing and destroying infected tissue, improving air flow, and applying appropriate fungicides or bactericides according to guidelines. For abiotic issues, adjusting irrigation, fertilization, and environmental conditions (e.g., providing shade or improving drainage) can prevent recurrence. Early detection and integrated disease management are recommended.