Corn Growth Stage Determines Timing Of In-Field Applications


   During the month of June, the corn crop is getting ready for key reproductive milestones that can have a significant impact on yield potential. With crop health at stake, it’s extremely important to know the growth stage of each corn field before applying crop protection inputs or sidedressing nitrogen. 
   Determining the corn vegetative stage is essential to safe application timing for herbicides and fungicides. Your Channel Seedsman can help you determine corn growth stage during a Field Check Up Series visit. 
   Early corn growth is measured by the number of leaf collars, which is the point where leaves partially unclasp the stem of the plant. For example, a plant with three collars is at the V3 growth stage. If the lower stalk leaves have dried up and dropped off, the nodal triangle method is another way to determine growth stage. 

   While farmers focused on planting this spring, weeds may have taken a foothold in corn fields. When considering post-planting herbicide applications, it’s imperative to check product labels to make sure the crop’s growth stage is within application guidelines. Corn sprayed past the growth stage listed on an herbicide label can suffer damage, resulting in arrested ear syndrome, blunt ears or blank ears. 
   Also, due to delayed field work during the wet fall season, many farmers were unable to apply late-season anhydrous and are planning to sidedress nitrogen this season. The ideal window for early sidedressing is the V4 to V6 growth stage. Nutrient availability at this stage highly correlates with ear development and final grain yield.
   Corn growth stage is a necessary consideration for applying fungicides. If fungicide application is justified, generally the greatest return on investment comes from a single pass during the tasseling (VT) through silking (R1) stages. Before spraying, farmers should thoroughly review fungicide labels and tank mixing instructions to ensure safe application. 
   With a good understanding of corn growth stages, farmers can more confidently and accurately determine the best time to apply crop inputs. Visit for more information or see your local Channel Seedsman. ∆
   MORGAN SCHMIDT: Channel Technical Agronomist
MidAmerica Farm Publications, Inc
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