Loose Smut of Wheat Control

Symptoms

At ear emergence the whole ear is converted into a mass of loose black powdery spores in place of normal grain, while the rest of the plant looks healthy. The black powder blows away in the wind leaving only the bare central stalk of the ear. Affected ears often emerge slightly earlier than healthy ones. The fungus is carried inside the seed.

Damage

Every plant that shows a smutted ear gives no grain at all, so the yield loss equals the percentage of infected plants, which can be several percent and higher in fields sown with infected seed year after year. The black spores released at flowering infect healthy ears nearby and are carried into next season inside the new seed.

Organic & cultural control

Always use certified seed from a disease free source as the fungus lives inside the grain. A traditional method is solar seed treatment where seed is soaked in water for a few hours in the morning and then spread thin to dry in hot summer sun, which kills the fungus inside. Rogue out and destroy smutted ears before the black powder is released to reduce spread.

Chemical control

Treat seed before sowing with a registered systemic seed treatment fungicide such as carboxin plus thiram or tebuconazole, which kills the fungus living inside the seed. This is the most reliable control. Always follow the product label dose, use treated seed only for sowing and not for food or feed, and consult your KVK or agronomist for the correct product and rate.

Always follow the product label, the recommended pre-harvest interval, and your local KVK or agronomist. Pesticide approvals change, so verify before use.

Prevention

Use certified, fungicide treated seed every season and never save seed from a field that had smutted ears. Inspect the crop at ear emergence and pull out smutted ears into a bag before they shatter. Grow resistant varieties where available and keep seed plots especially clean.