Leaves of a corn crop naturally begin to senesce or die as the crop reaches physiological maturity, and several factors can influence the timing and pattern of leaf death. Environmental stress, hybrid characteristics, some form of insect damage and the anthracnose pathogen all can cause leaf death. It is important to watch for early symptoms of crown and stalk diseases, including anthracnose top dieback, to help plan harvest priority.
Diagnosing Anthracnose Top Dieback
Top dieback in corn caused by the anthracnose fungal pathogen, Colletotrichum graminicola, will be random or scattered in the field. Iowa State University Extension points out that the pathogen infects plants early in the season through the whorl or leaf sheaths but remains dormant. Late-season stress triggers pathogen symptoms, which include a dead, yellow or purple flag leaf and black lesions on the stalk. The pith of the stalk will appear rotted, causing reduced water movement to the top of the plant and potentially early death ofthe top leaves.
Management
While there’s not much that can be done about this disease at this point in the season, losses can be minimized by harvesting and chopping the worst impacted fields first. The longer infected corn plants stand, the more likely they will lodge, due to their reduced stalk integrity.
Consider management practices such as crop rotation or future hybrid selections with better disease resistance. Visit with your local Golden Harvest Seed Advisor with questions or for more agronomic insights.
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