Fungicides On Wheat: Timing Is Critical

SPRINGFIELD, MO.

    “Apply fungicide to wheat at the early boot stage to head emergence,” said Jay Chism , MU Extension Agronomy Specialist in Barton County. “Research shows fungicides at this growth stage, when the flag leaf is in danger of infection will provide the most benefit.”

   There are several foliar fungal diseases that can cause yield loss on wheat in southwest Missouri.

   According to Laura Sweets, MU Plant Pathologist, leaf rust, strip rust and Septoria leaf blight are diseases that are likely to cause yield loss.

   “The incidence and severity of these foliage diseases will depend on the weather conditions during the growing season,” said Sweets. “The susceptibility of the variety to each of these diseases and the amount of inoculum in each field will also determine the severity of disease infection.”

   Most wheat foliage diseases are favored by warm, wet conditions. Frequent light rains, heavy dews, high relative humidity and warm temperatures are ideal for the buildup of foliage diseases.

   “It is important to scout wheat fields for diseases,” said Chism.

   It is also important for growers to know the difference between viral and fungal diseases.

   “Several fields in the area are showing signs of viruses, but only very limited fungal pathogens have been found,” adds Chism. “Fungicides will have no effect on viral diseases.”

   If fungal diseases are threatening to infect the flag leaf, then Chism says applying foliar fungicides is a good practice. Still, farmers need identify the disease and the severity before they make that determination.

   For more information on applying foliar fungicides to wheat contact Jay Chism in the Barton County Extension Center at (417) 682-3579. Δ