The last couple of days the weather has given us some dry sunny weather with high winds. This has been great to have fields finally dry off and make strides with planting any remaining acres. Unfortunately, this also exposed young small grain seedlings to the same conditions. The daytime heat at the soil surface has caused heat canker. The tender young tissue at the soil surface basically has been ‘cooked’ and this appears as a yellow band that is slightly constricted (Photo 1). As the leaf continues to grow, this yellow band (1/8 - 1/4") moves upward and away from the soil surface. If the hot and dry weather lasts for several days, repeated bands can become visible. Because of the high winds, the tips of leaves may break off at the yellow band and give a field a very ragged appearance. Damage from heat canker is temporary and should not affect further growth and development.
Photo 1 – Barley seedlings with the yellow, constricted appearance
symptomatic for heat canker