As winter grains are heading out and flowering, it’s time to start scouting your fields for loose smut (Ustilago nuda, Ustilago avenae, and Ustilago tritici). Loose smut is found in winter and spring spelt, barley, and wheat, as well as oats.
Spelt and barley are particularly susceptible to infection. Loose smut is one of the easiest grain diseases to spot in the field. During spike or head emergence, diseased heads emerge slightly earlier than healthy ones and appear as a mass of dark brown spores covered with paper-like membrane. This membrane tears easily as healthy plants begin to flower, and windblown spores infect the embryos of developing seed. After the fungus invades the grain seed embryo, it remains dormant until the seed is planted and germinates. Infected plants appear to be normal, but develop smutted heads.
Planting contaminated seed, especially in organic systems, can exponentially increase grain infection rates, resulting in yield reductions; 100% of the smutted heads are lost. Eating loose smut infected grain poses no harmful health effects and doesn’t appear to impact baking quality.
Control
If you find loose smut in your fields, don’t save the seed.
- Plant certified or otherwise high-quality, disease-free seed.
- Plant resistant varieties.
- Infected seed can be treated with various systemic fungicides in conventional systems.
- In organic systems, hot water seed treatment can be used to rid infected seed of the Loose smut fungus.
For More Information
If you have questions about loose smut or any other plant disease, the University of Vermont Plant Diagnostic Clinic can help. Click on the link below for details on submitting a sample for identification: http://pss.uvm.edu/pd/pdc/pdf/pdcform.pdf.