Avoiding Arrested Ear Development

We’ve heard questions lately concerning Arrested Ear Development (AED). While there are many things that remain unanswered as to why this occurs, here’s what we do know.

Arrested ears are corn ears that have shortened cobs and less grain produced. Ear size and kernel development can vary from barren to near normal. It is not a disease, but a physiological disorder. When a high percentage of corn plants exhibit this disorder, yield losses can be significant. 

During the past 15 years, many reports have been made identifying AED. There appears to be a time in the growth stage of corn when this injury is more prone to exist—V14 to V18 (pre-tassel). Most incidences seem to have been caused by a fungicide application using a non-ionic surfactant (NIS) or crop oil concentrate (COC). These adjuvants are added to allow the fungicide to penetrate more easily into leaf tissues, but many contain Alkyl Phenol Ethoxylate, which has been linked to AED. 

If you must treat with a fungicide in the V14 to pre-tassel window, do not use a NIS or COC. Once corn has grown to full tassel emergence (VT-R1 and beyond) it is safer to add NIS and COC to assist the fungicide to enter the plant with less risk of AED. 

PRO-TIP: If you treat your corn with fungicide during the pre-tassel stage, your crop may still require an additional fungicide spray to protect the uppermost leaves from disease later in the season, as they were not exposed at the time of application.

Always read and follow the label directions of the fungicide chosen for the application. Adjuvants vary between products. Reading the label will help you avoid adjuvant and tank mixing issues.