Black bundle disease

Black bundle disease, caused by the fungus Sarocladium strictum, is a notable pathology affecting corn (maize) production globally. The pathogen acts as an opportunistic fungus that colonizes the vascular bundles of the plant, disrupting the transport of nutrients and water, which eventually leads to tissue decay within the ear and stalk.

The primary host for this disease is maize. Infection often occurs during the silking stage or via mechanical injuries caused by insects or machinery. Once inside the host, the pathogen migrates through the vascular tissues, becoming established in the ear shanks and the internal parts of the ear, which characterizes the disease's name.

Symptoms are typically identified by black discoloration appearing on the stalk nodes or the vascular bundles of the ear shank. In advanced cases, the ear becomes shriveled, and the kernels may be discolored or develop a fine, black fungal growth, significantly impacting the structural integrity of the cob and the overall seed health.

The development of Sarocladium strictum is highly dependent on environmental conditions, specifically high temperature and high humidity during the reproductive phases of corn development. Stress factors, such as drought or nutritional imbalances, make the plants more susceptible to colonization by this opportunistic fungus.

• Selection of resistant corn hybrids.
• Rigorous management of crop debris through tillage.
• Implementation of balanced crop rotation schemes.
• Use of certified, fungicide-treated seeds.
• Integrated pest management (IPM) to minimize plant injuries.

The economic impact of black bundle disease is significant due to yield losses and the potential presence of mycotoxins in the infected grain. Prevention remains the primary strategy for managing this disease, as chemical control during the mid-season stages is often ineffective once the pathogen has colonized the internal plant tissues.