Diplodia ear rot

Diplodia ear rot is a widespread and destructive fungal disease in corn caused by the pathogen Stenocarpella maydis. This fungus primarily attacks the ears, stalks, and leaf sheaths of maize, significantly impacting grain yield and overall plant health during the maturation phase.

The primary symptom is the appearance of a thick, white fungal growth that typically starts at the base of the ear and spreads upwards, sometimes enveloping the entire ear. As the infection progresses, the husk leaves may appear bleached, and the kernels become lightweight, discolored, and break easily. Tiny black dots known as pycnidia develop on both stalks and ears.

Disease development is heavily favored by wet and humid conditions, particularly during the silking stage and grain filling. The fungus overwinters in crop debris left on the soil surface. Spores are then dispersed by wind and rain splashes to healthy plants, initiating new infection cycles across the field during the growing season.

The impact of this disease is severe, as it leads to substantial yield loss and potential contamination of the grain with mycotoxins. Such toxins pose serious health risks to livestock, particularly swine, which are highly sensitive to contaminated feed. Consequently, grain quality and market value are significantly degraded, causing economic damage to farmers.

Management of Diplodia ear rot relies on an integrated approach centered on prevention and field hygiene. Crop rotation is highly effective, as it allows for the natural decomposition of infected debris. Furthermore, choosing hybrids with tight husks and good resistance, combined with reduced-tillage practices or deep plowing, helps minimize the primary inoculum in the field.

• Implementing 2–3 year crop rotation cycles.
• Selecting corn hybrids resistant to ear and stalk rots.
• Deep plowing to bury infected plant residues.
• Using high-quality seed treatments to protect seedlings during germination.