Corn drying from the top down may be anthracnose top dieback
Corn senescing or dying from the top down may be caused by one of several problems, including anthracnose top dieback.
Some fields in Tuscola County, Mich., are dying from the top down. Similar symptoms were noted in Tuscola County in 2009. Corn dying from the top down can be symptomatic of drought stress, European corn borer, or anthracnose top die-back.
With anthracnose top dieback, symptoms also include black lesions that are visible on the outer stalk tissue behind the leaf sheaths. If the stalk is split, the pith appears rotted or discolored in the upper internodes. See Iowa State University Extension’s related article, Anthracnose top dieback is back. Anthracnose is a fungal disease caused by Colletotrichum graminicola.
Yield loss to anthracnose top dieback is due to loss of the ability of upper leaves to photosynthesize. Yield losses are greater the earlier symptoms appear. There’s nothing that can be done to treat the disease once symptoms develop. But, steps can be taken to reduce the likelihood of disease development in future years.
The most important thing growers can do is to choose hybrids that are less susceptible to the disease. The corn hybrids grown in the 2011 TARE trials will be rated for susceptibility to diseases, including anthracnose.
The anthracnose does survive in corn residues. Therefore, there can be a tendency for the disease to become more serious under no-till or reduced tillage systems. A two-year rotation away from corn would be helpful under no-till or reduced-till systems. In conventional-till situations, a system that completely buries residue and at least one year away from corn will help in managing the disease.
Finally, good agronomics, including a sound fertility program based on soil testing, and appropriate planting populations will help the corn withstand pest pressures, including anthracnose.