Early Season Corn Growth & Development

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Early Yellowing of Young Corn

• At about the V3 stage of growth, corn plants start to rely on the developing nodal root system to acquire the carbohydrates they need to grow.
• If plants are under stress around V3, the seedlings may stall out in growth and appear paler than normal.
• Several factors can result in stalled growth in corn, including temperature changes, cloudy weather, root pests and pathogens and ammonia injury, among others. 
   

At approximately the V2-V3 stage of corn development, the corn plant starts to shift from relying on the seed for nutrients and carbohydrates to the new nodal root system, in conjunction with the photosynthetic capabilities of the leaves.  When growing conditions are favorable and the seedling corn plant is healthy, this transition is nearly seamless.  However, the impacts of pests, pathogens, poor climate, or other stress factors can result in issues with plant growth.

Results of stress on V2-V3 corn seedlings may appear to stall out in growth, and color may fade from dark green to yellow-green.  This growth hesitation normally doesn’t last long, and corn plants quickly resume their normal growth and return to a darker green color.  Nonetheless, this slowed down in growth and resulting aboveground symptomology can be a little disconcerting. If this V3 stall in seedling corn growth shows up in your area, take the opportunity to investigate the possible contributing factors.  Certainly, a sudden shift from warm to cool weather is one of the most common sources of stalled growth. Another potential cause is an extended period of cloudy weather that can reduce photosynthesis and cause a growth slow-down.  Pests or pathogens that attack the new nodal roots or mesocotyl are also common sources of slowed seedling corn growth.  These issues will often be less uniform in their expression across the field than are cool or cloudy weather-related issues.  In addition, consider things like root injury from free ammonia in the soil.  This kind of injury may take on a distinct field pattern.

Be assured that the V3 growth stall rarely lasts long, unless there is a serious underlying problem.  Once the nodal roots contact and start taking up soil nutrients, the color and growth rate of the seedling corn will improve.