Counting corn leaves: Why is this important?

  • Jun 11
    Chuck Belanger
    Counting corn leaves: Why is this important? By Chuck Belanger on June 11, 2013
    Categories: Crop Physiology, Grain Corn, Silage Corn, Weed Control

    There are many reasons why it is important to know how to count your corn leaves. Counting corn leaf stages properly is critical in determining the timing of post-emergence herbicide application.

    There are several methods of leaf staging, but the leaf-over method is what most herbicide product labels base their recommendations on. The leaf-over method is fairly easy. All you need to remember is that you only count the leaves that are bent over. The leaf standing erect out of the whorl is not counted. Sounds easy, right? There are a couple of factors you need to remember. If you have a frost event like we did a couple of weeks ago, a leaf or two may have dropped off and may not be completely visible. This is important. It could mean problems if you are planning to spray Marksman® Herbicide on your corn. Marksman® can be applied up to the 5 Leaf Stage, according to the manufacturer. If you miscount your corn and miss the bottom 2 leaves that may have fallen or died off and count 5 leaves, then you are actually spraying 7 leaf corn. This opens your corn crop up to possible herbicide injury.

    This illustration is from Publication 75 – Guide to Weed Control.  It is pretty easy to follow.  Always remember to count the bottom leaves. They may be hard to see, so get down and dirty to have a look.

    Chuck Belanger, Maizex Seeds Yield Specialist, North Essex and South Chatham-Kent Counties
    Twitter: @sprayman63