Wheat Black Rust (Stem Rust) Control

Symptoms

Large, elongated, dark reddish brown to brick red powdery pustules mainly on the stem, leaf sheaths and sometimes on leaves and ear. The pustules break through the surface roughly and the powder is dark. Later the pustules turn black as black spores form, giving the disease its name. It needs warmer weather and usually appears late in the season, mainly in central and peninsular India.

Damage

Black rust is historically the most destructive wheat rust and a severe attack can shrivel grains, weaken and break stems causing lodging, and in epidemics cause very heavy yield losses up to total crop failure on susceptible varieties. It is most dangerous when it strikes early and in warm humid weather.

Organic & cultural control

Grow resistant varieties recommended for your zone, which has kept black rust largely under control in India. Sow at the recommended time, especially in central and south India where late sowing increases risk because the crop is still green in warm weather. Use balanced fertiliser, remove volunteer plants and scout the lower stems and sheaths late in the season, reporting any brick red pustules to your KVK at once.

Chemical control

If black rust appears, spray a registered triazole fungicide such as propiconazole 25 EC or tebuconazole with thorough coverage of stems and lower foliage, repeating as per label if the disease spreads. Always follow the product label dose, observe the pre harvest interval and consult your KVK or agronomist before spraying.

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 seed of resistant varieties and sow on time so the crop matures before warm rust favouring weather. Avoid late sown wheat in central and south India. Destroy self sown wheat and where present remove nearby barberry bushes that act as alternate hosts in the hills. Follow KVK rust surveillance advisories.