Puccinia striiformis
Scientific Name:
Scientific Name:
Crops:
Crops:
- Common wheat
- Durum wheat
- Wheat
- Cereals (durum and soft wheat)
- Grain
Biology
Control Method
Biology
Definition
Foliar disease of cereals due to a fungal pathogen. It mainly affects common wheat, its early appearance and irregular presence make it difficult to detect.
When detected late, the fight is more difficult and the damage can be very high. In 2004, this disease, which was thought to have no impact, exploded and this was not due to chance, as the high proportion of susceptible soft wheat and favourable climatic conditions explain this phenomenon.
Development Lifecycle
After harvesting cereals, the uredospores will only find fairly resistant grasses as a backup host. This will result in a huge loss of inoculum because the spores are not resistant to the high ultraviolet (UV) rays in summer. Germination takes place in the dark in the presence of humidity.
In spring-winter (the earliness depends on the climatic conditions), the first outbreaks of 1 to 2 m² appear. In favourable conditions (overcast sky, wind, temperature and humidity), the large quantities of spores produced by these outbreaks will invade the plot to create uniformly distributed and significant contamination. After two to three cycles, all the foliage is destroyed.
Symptoms
On the plot: Small-area (1 to 2 m²), yellow from a distance, clearly delineated. If the climate is favourable, these outbreaks can then infest the entire plot.
On sheets:
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On the upper leaves, the yellow, sometimes orange-coloured pustules are aligned between the veins, until they form streaks. The pustules are often small (0.5 mm).
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Elongated chlorotic spots in the direction of the veins without pustules may also be encountered (pustules still in incubation).
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At an advanced stage of the infestation, the yellow streaks give way to black pustules.
Soprochiba tip:
During your observations, look mainly for the affected leaves and observe yellow pustules lined up with a pocket magnifying glass.
How not to confuse yellow and brown rust:
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Stripe rust: first divided into foci. Pustules aligned along the veins.
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Brown rust: homogeneous distribution in the field. Pustules scattered over the entire leaf.
Contributing factors
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Susceptible varieties are a contributing factor.
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The presence of infected volunteers in the field as well as weeds (such as: Upper Borage), promotes the conservation of the disease.
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The presence of nitrogen increases the sensitivity of the plant. Nitrogen fractionation is unfavourable to the disease.
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The presence of wind helps the spread of spores.
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On average, the days favourable to contamination should have the following characteristics:
Average temperature above 4°C
Minimum temperature above 2°C.
A relative humidity above 80% for 18 hours.
Night-time temperatures should be quite low, preferably below 15°C.
Control Method
Recommended Prophylactic and Cultural Method
- Varietal resistance remains the most effective and economical means of controlling stripe rust.
Chemical method
- The action level against yellow rust must be triggered from:
- From the ear stage 1cm, in the presence of active foci of stripe rust (powdery pustules).
- From the 1-node stage: as soon as the first pustules are present in the plot.
