Stem scald

Stem scald is a specific fungal disease caused by the pathogen Gibellina cerealis, which primarily targets various cereal crops. As a specialized parasite, this fungus disrupts the structural integrity of the stems, leading to weakened plant stalks and significant physiological stress during the critical phases of grain development.

Winter wheat is the primary host for this pathogen. The fungus typically attacks the lower parts of the stem during the early spring growth stages. The infection process involves the penetration of the fungus into the plant's vascular tissues, which eventually compromises the plant's ability to transport water and essential nutrients upwards to the ear.

Symptoms are distinct and often referred to as "scald" due to the bleached or discolored appearance of the stem nodes. Affected areas may look pale or whitish, eventually showing small dark fruiting bodies of the fungus. The stems become brittle and may collapse, significantly impacting the structural stability of the plant canopy as the season progresses.

The development and spread of Gibellina cerealis are heavily influenced by environmental conditions, particularly high humidity and cool to moderate temperatures during the tillering and elongation phases. The pathogen survives effectively in crop residues and soil, making fields with high stubble loads particularly vulnerable to persistent infections if not managed correctly.

The economic impact of Stem scald can be substantial, leading to reduced grain filling, smaller kernel size, and potential yield losses in affected patches. To minimize the risks, integrated management practices are essential, including:

• Implementing crop rotation sequences to break the pathogen's life cycle.
• Ensuring thorough incorporation or destruction of crop debris after harvest.
• Selecting certified, fungicide-treated seeds for planting.
• Applying systemic fungicides at the early onset of spring development if environmental conditions favor disease progression.