Recognize the problem
Stem rust is caused by a fungus. The fungus produces symptoms on almost all above-ground parts of the plant, especially the stem and leaf sheathes. At the initial stages of the disease, long, narrow streaks of red, dusty spots (pustules) are formed on all green parts of the plant. These spots are brick red in the beginning and become black at maturity. Moisture and warm weather favour the development of this disease, which usually appears at the heading stage. The fungus weakens the plant by taking its nutrients.
In nature, stem rust disease requires a living host for its growth and reproduction and cannot exist independently. The disease arrives at a new plant after being spread by the wind, usually travelling from the hills to the plains. Stem rust is favoured by hot days, mild nights and rain or dew that causes leaves to become wet. The disease can spread to healthy plants via running water, for example rain splash or water channels. The overuse of nitrogen also favours the development of the disease.
- Practise crop hygiene by removing volunteer wheat, as it can provide a green bridge for rust carryover
- Cultivate early sowing and early maturing varieties
- Destroy diseased tillers and cereal grass weeds, especially volunteer wheat
- Avoid heavy doses of nitrogenous fertilizers
- Cautious use of potassic fertilizer helps to minimize the susceptibility of plant
- When deciding if a fungicide spray is needed, consider crop stage and potential yield loss
When using a pesticide, always wear protective clothing and follow the instructions on the product label, such as dosage, timing of application, and pre-harvest interval.