However, whole fields of barley in southern Alberta may turn yellowish in colour. Spots usually appear about halfway down from the leaf tip, sometimes causing the leaf to break and die. In southern Alberta, barley that is seeded in July into soils with a pH of 8 may turn yellow, or the leaves may become stippled with yellow spots during dry periods. However, with additional moisture, new growth may be green and healthy and show no evidence of manganese deficiency. The degree of yield loss is related to the unavailability of manganese.
Grey speck is usually of minor importance, but can cause crop failures in some areas.
Loss of photosynthetic area and, in some instances, failure to produce heads contributes to yield loss. Diagnosis Take representative soil samples at 0-15 cm and check them for manganese availability. Management Strategy Use oat varieties known to be tolerant to manganese deficiency. Grow wheat and barley, which are less affected by this deficiency. Spraying the crop with 1 percent manganous sulphate can reduce losses.