A number of calls have come in regarding fields of pale, yellow corn. This symptom is not unusual for Michigan but seems to be particularly prevalent this spring. The pale yellow color of the plant is symptomatic of low photosynthetic activity and general nutrient stress experienced by the plant. The main culprit is the cool wet weather, which has characterized the early Northern growing season. Many factors contribute to the symptom of yellow corn seedlings.
Sunlight drives the photosynthetic process and a lack of heat units results in slow seedling growth.
The cool spring temperatures combined with saturated soils have also limited corn seedling root growth and penetration into the soil. This confounds the slow growth of the corn plant by limiting nutrient uptake. Furthermore, the mineralization and plant availability of some nutrients is slowed down due to slower microbial activity in cool wet soils. In addition, weather-stressed corn is more susceptible to herbicide injury, which can also result in yellowing. Finally, weakened plants are more susceptible to damage from insects.