See photo 29 . 29 Hail injury occurring on small grains in the preboot stage can cause the grain head to curl up inside the sheath, resulting in twisted heads that are partially exposed and hanging down. The effects of hail injury can also be similar to injury from dicamba applied too late. Color Banding Color banding occurs on young grain seedlings because of temperature changes. It is commonly associated with deep planted grains.
Color banding occurs when temperatures at the soil surface fluctuate widely.
Newly emerged grain plants will exhibit alternate color bands of yellow and green leaf tissue that correlates with high and low temperatures. Color banding can sometimes occur when water laden or frosted leaves are quickly dried by surface heat generated by solar radiation. Emerging leaf tissues of small grains are sensitive to temperature extremes, but quickly lose their sensitivity with age. See photo 30 . 30 Coleoptiles of small grain seedlings exposed to fluctuating temperatures at the soil line exhibit yellow and green color bands.