Late wilt of maize

Systematic position and pathogen nature. Harpophora maydis (formerly Cephalosporium maydis) is a soil-borne fungal pathogen classified within the kingdom Fungi. It is the causal agent of late wilt, a devastating vascular disease in maize. The fungus colonizes the plant's xylem vessels, causing a systematic blockage that disrupts vital water uptake.

Host plants and associated diseases. The primary host of this pathogen is maize (corn). The disease typically appears during the grain-filling stage, making it particularly damaging to yield potential. Symptoms are characterized by a rapid, wilting appearance of the plant, straw-colored lower stems, and significant darkening of the vascular tissue inside the stalk, often leading to early plant death.

Biology and life cycle. The pathogen survives as mycelium or chlamydospores in the soil and on crop debris. Infection begins when the fungus penetrates the root system of a susceptible plant. Once inside, the fungus spreads rapidly through the vascular bundles, producing microconidia that further colonize the plant, resulting in total blockage of water transport.

Conditions for spread and economic impact. High soil moisture during early growth followed by high temperatures and drought stress are ideal conditions for disease outbreaks. The economic impact is severe, resulting in poor kernel filling, stunted ear development, and increased lodging, which complicates mechanical harvesting and leads to substantial yield losses in infested fields.

Protection and control measures. Management of this disease requires an integrated strategy to reduce inoculum levels in the field. Key measures include:

• Strict crop rotation with non-host species for several years.
• Planting resistant or tolerant corn hybrids developed for specific regions.
• Proper disposal or deep burial of maize stalks to accelerate fungal decomposition.
• Application of seed-applied systemic fungicides to protect the crop during the early establishment phase.