Why are the leaves on my corn turning yellow?
Corn Has Yellowing Leaves
Certified GKH Gardening Expert
A number of things can lead to yellow leaves. This article can help pinpoint likely causes: https://www.gardeningknowhow.com/plant-problems/environmental/plant-leaves-turn-yellow.htm
For more corn specific reasons, look toward cooler temps, wet soils, or nutrient deficiencies (a soil test can help determine this).