See:
Fungicide Effectiveness as Seed Treatments for Cereal Diseases
Cause A fungus, Ustilago tritici, carried inside seed, infects wheat, triticale, rye, and some grasses. Wind-blown spores infect flowers and grow into seed. Infection is favored by cool, humid weather.
Symptoms Infected leaves may have dark green, erect leaves with yellowish streaks. Black infected heads are evident as soon as they emerge from the boot. Spikelets are transformed into a sooty black spore mass, which soon disperses in the wind. By harvest, only the bare white central axis of the head remains. Infected seed is not visibly altered and will germinate.
Testing For a fee, the OSU Plant Clinic tests uncertified seed samples for loose smut. For more information, see "Plant Disease Clinics" in "Testing Services" in Section 2.
Cultural control
- Plant certified smut-free seed. Do not use seed wheat from fields with loose smut.
- Use resistant varieties.
- Seedborne inoculum can be destroyed with hot water treatments.
Chemical control Seed treatment with a systemic chemical controls the disease.
- Charter (Group 3) at 3.1 fl oz/100 lb seed plus a dye. See label for rotation and reentry restrictions.
- Dividend Extreme (Group 3 + 4) at 2 to 4 fl oz/100 lb of winter wheat, spring wheat, or triticale seed. See label for reentry restrictions.
- Dividend XL RTA (Group 3 + 4) at 2.5 to 10 fl oz/100 lb of wheat seed. Do not graze green forage until 55 days after planting. See label for reentry restrictions.
- Raxil MD (Group 3 + 4) at 5 to 6.5 fl oz/100 lb seed plus a dye. See label for reentry restrictions.
- Vibrance (Group 7) at 0.08 to 0.16 fl oz/100 lb seed plus a dye. See label for reentry restrictions.
- Vitavax (Group 7) at 2 to 3 fl oz/100 lb seed plus a dye. Do not graze livestock in treated areas for 6 weeks. See label for reentry restrictions.