Several Corn Ear Disorders Spotted Due To Drought

LAMAR, MO.

Brie Menjoulet, agronomy assistant with University of Missouri Extension in Hickory County, scouted fields northwest of Lamar and in the Liberal area on Aug. 17.

   Corn fields that were scouted were in reproductive stages, 7/8 to maturity.

   Several forms of corn ear disorders such as numbed ears, incomplete kernel set, and tassel ear, also known as crazy top, were noticeable in the fields. “The problems are most likely due to the summer drought. The moisture level in some of the harvested corn was at about 17 percent,” said Menjoulet. “A greenish mold was present on several ears and though mold does not necessarily indicate aflatoxins, higher moisture levels coupled with drought can increase the likelihood of these chemicals in the kernels.”

   Aflatoxin levels can vary greatly from kernel to kernel and can be patchy throughout a field. The FDA has set an aflatoxin limit of 20 ppb or one contaminated kernel per 5lb of corn.

   The University of Iowa has guide on sampling corn for quantitative aflatoxin testing and is available online or at your local Extension office.

   “Though conditions seem favorable for aflatoxins, no confirmed cases have been reported yet,” said Menjoulet.

   Soybeans scouted this week were in the R2 stage. Defoliation was primarily due to grasshopper feeding but it has remained minimal at five percent or less.

   “If defoliation reaches 30 percent or more, intervention may be needed to prevent yield loss. I also caught a few scattered fall armyworms in one field but did not observe any stem or root diseases this week,” said Menjoulet. Δ