Williams Crop Update – November 29, 2023

All information is representative of the Williams County Area. Based on the Bryan Zip Code, about an inch of precipitation fell over the Thanksgiving weekend into early this week. Corn is around 85% harvested and yields are averaging between 180-200 bushels per acre; however, the quality has been poor, this is due to vomitoxin and low-test weights. Test weight is a measurement of bulk density, or the weight of corn per unit of volume, and is expressed as pounds per bushel. The “standard” test weight for corn is 56 pounds per bushel. Currently, the corn is coming into the grain elevators at 22-23% moisture.

Over the past month, there has been trouble with vomitoxin, resulting in some corn being rejected from grain elevators. Gibberella ear rot is caused by the fungus Gibberella zeae (also known as Fusarium graminearum), the same pathogen that causes stalk rot in corn and head scab in wheat. The fungus causes a pinkish-white mold to develop at the tip of the ear. During infection and colonization of the ear, the fungus produces several mycotoxins, including deoxynivalenol (DON), also called vomitoxin. As a result, high levels of Gibberella ear rot severity and moldy grain are usually accompanied by high levels of vomitoxin. It is the most prevalent of secondary fungal metabolites. The mold grows on wheat, corn, oats, barley, and other grains. This mold develops under wet conditions and enters the plants through silk or wounds during wet conditions during the silking stage (R1 growth stage), which promotes spore production, leading to more infected plants. For more information on vomitoxin please contact your local extension office.

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