Reports of wheat damaged by Fusarium head blight (head scab) have continued this week. Fusarium infections have important implications for farmers who are considering saving their wheat for seed.
Fusarium head blight infects the developing wheat heads during flowering or early stages of grain development. The disease continues to spread within the head as the fungus grows through the central stem of the head called the “rachis.” The grain is directly affected by the infection, resulting in shriveled, light-weight kernels. The diseased kernels will often have a white, chalky appearance or a pink discoloration.
These diseased kernels will reduce the test weight of the grain and can cause problems if the grain is used a seed. The Fusarium fungus can reduce germination and cause seedling blights in seed lots with severe infections. Fortunately, there are a few options that can greatly improve the prospects of using this grain as seed.
Clean the wheat to removed mostly severely disease kernels. Many of the Fusarium-damaged kernels can be removed from a seed lot with cleaning equipment that removes the diseased kernels from the healthy seed.
Check the germination of the seed lot and use a fungicide seed treatment. It is not uncommon for seed lots with large amounts of Fusarium-damaged kernels to have a germination rate less than 85% in germination tests. The poor performance in germination tests is due in part to ideal conditions for fungal growth during the germination test. In most cases, a fungicide seed treatment can improve the germination rate to 95% or better. The fungicide seed treatment will help reduce the risk of a severe problem with seedling diseases caused by Fusarium during stand establishment.
For more information on fungicide seed treatment product options see the publication: Seed Treatment Fungicides for Wheat Disease Management at: http://www.bookstore.ksre.ksu.edu/pubs/MF2955.pdf
Erick DeWolf, Extension Plant Pathology