Small Grains

 

Frost Damage

Mary E. Burrows, Montana State University, Plant Sciences and Plant Pathology

 Jeff Stein and  Ned Tisserat

 

Cause:  Environmental 

·         Varieties vary in their susceptibility to frost damage, probably due to the plant growth stage at which freezing injury occurs.

 

Key Symptoms: 

·         Symptoms depend on time of temperature stress and growth stage of the plant (see table below)

·         Plants with optimum growing conditions including fertility are the most susceptible to frost damage because of their lush growth and high moisture content.

·         Wheat is most susceptible to freeze injury during reproductive growth.

 

 

 

Degree of injury depends on duration as well as the low temperature reached.

 

Management Approaches

Cultural management practices

·         Avoid locating wheat fields in low lying areas that allow cold air to settle over field or in areas that are prone to periodical freezing temperature events in late spring.

·         Harvest for grain: Depending on the severity of the injury, the grain may still be harvestable. Tillers can compensate for some yield loss. Lodging and shatter may be increased.

·         Seed germination may be reduced. Check before planting. Condition seed to remove shriveled and light-weight kernels.

·         Cutting for hay or silage may be the most economical use of freeze-damaged wheat. Check nitrate content before feeding to cattle, as the plant can still absorb nitrate from the soil but lack the grain to use the nitrogen, causing the nitrate to accumulate.

• Cattle on wheat hay or ensilage that was cut after the anthesis (flowering) growth stage should be closely observed for development of actinomycosis, commonly known as ‘big jaw’ or ‘lumpy jaw.’ The problem occurs when tissues inside the mouth of cattle are punctured by wheat awns and become infected. Actinomycosis is less likely when wheat is cut at young stages of maturity and when it is fed as ensilage than when it is fed as hay.
• Freeze-injured wheat needs to be killed with an herbicide if it is not cut for hay or silage, as it may become a weed in subsequent crops.
• If the wheat is not removed it should be chopped to avoid drying the soil.

 

 

 

Categories: Small grains, Diseases, Frost Damage

 

Date: 02/06/08