The dark green fields we see throughout southwest Iowa and northwest Missouri this summer are very quickly turning brown, indicating the end to another growing season. While this color change is not unusual, what is of concern is how quickly it is occurring.

To look for Anthracnose stalk rot (ASR) we need to take a step back into the growing season. First, we need to check the distribution in the field. It is rare for a disease to infect an entire field. Symptoms of top dieback occur on random plants. Secondly, we need to peel back the leaf sheath at the top of the affected area and look for black anthracnose lesions. If you see a pink jellylike substance on the stalk, it is likely to be anthracnose. If you split the stalk the pith will appear rotted or discolored in the upper internodes.

A fungicide application at flowering could indirectly reduce anthracnose, by reducing foliar disease severity and thus late-season plant disease. Another way of controlling anthracnose is to plant a hybrid with ASR tolerance. LG Seeds has several of them in all maturity groups. Talk to your local Sales Area Manager or Technical Team Agronomist to get a recommendation of the best hybrid to combat this for your area.

Most of the browning across this area, however, is most likely due to premature senescence of plant leaf tissue, due to several environmental stresses during summer. For example, extreme drought in southern Iowa and northern Missouri. There were several days with temperatures around 100 degrees, with heat indexes hovering around 110.  With the heat and drought stress many of these corn fields called it quits for the 2018 growing season.

Sources & Additional Information:
https://crops.extension.iastate.edu/cropnews/2015/09/why-all-corn-dying-anthracnose-blame 
https://www.agry.purdue.edu/ext/corn/news/timeless/topleafdeath.html

Note: The information in this issue is based upon field observations and third-party information. Since variations in local conditions may affect the information and suggestions contained in this issue, LG Seeds disclaims legal responsibility therefore. Always read and follow label instructions.
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Download a copy of this Technical Bulletin: Tech_394 - Top dieback in corn