Diseases of Wheat

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Septoria is confined to the lower leaves even in untreated trial plots in more resistant varieties like RGT Saki

General Information

Keeping a Lid on Winter Wheat Disease Risks

If there has been early drilling and benign winter conditions, winter wheat crops may be more advanced than usual this season. This article outlines how to keep on top of any disease risk. Read more here.

Spotlight on Manganese Deficiency in Spring Cereals

Manganese (Mn) deficiency is particularly common in spring barley and can lead to yield losses if left untreated. Soil applications of Mn are generally ineffective, as the applied Mn rapidly changes into less available forms. Deficiencies are best prevented or, where Mn deficiency only occurs infrequently, corrected by foliar sprays with Mn each year. Read more here.

**Leaf Stripe (Cephalosporium)**

Cephalosporium leaf stripe is an increasing problem on farms in Scotland where wheat is grown on short rotations. Incidences of the disease have increased in recent years as a consequence of changes in cropping practice and weather patterns, in particular rainfall. Read more here.

A close up of an infected leaf showing the yellow pustules and the clear stripes that are characteristic of the disease

Yellow Rust

Yellow rust is a major disease in wheat. Typical symptoms comprise small yellow pustules on the leaves. They commonly form in lines along the leaf. Look out for small pockets of affected plants in the spring. In severe cases, the leaves will appear bleached. Read more here.

About the Disease

Yellow rust overwinters on wheat volunteers. Conditions which favour the disease are cool and humid conditions. The disease may overwinter on crops, but it rarely flares up until the spring and early summer. Yellow rust is specific to wheat, but it will spread onto other varieties of winter and spring wheat. Diversifying wheat varieties is one way to limit the spread from one crop to another.

The most effective way to avoid yellow rust is to grow resistant varieties. The popular variety Robigus is however susceptible to yellow rust. Diversification Schemes can help reduce the spread of the disease. This allows growers to choose a mix of varieties which have different resistance characteristics. As such, when yellow rust attacks on variety, you can choose a variety to sow in neighbouring fields which may be resistant to different races of yellow rust.

Further Information

Understanding This Season’s Yellow Rust Breakdown (July 2025)

New Yellow Rust Strain Confirmed (June 2025)

Ergot

About the Disease

Ergots are fungal resting bodies which contain toxic alkaloids, they are very poisonous to both humans and livestock. Ergots are purplish black in colour, and a similar size to grain, but smaller pieces of ergot may also be present. The tolerance level for ergots for human consumption is 0.001 % by weight. In practice, grain samples with any ergot may be rejected. It is possible to screen out some ergot, but ergot levels become concentrated in the screenings, and contaminated screenings must be buried or burnt.

Ergot occurs in barley, wheat, triticale, oats and rye, as well as many grasses. The main sources of the disease are grasses, ergot contaminants sown with the seed and shed ergots. The fungal bodies remain viable in the soil for about 1 year, but in dry storage they can survive longer.

Ergots germinate in spring and summer to produce spores which infect grasses and cereals at flowering time. Secondary infections can then take place from head to head. The ergot bodies then develop in the grain sites, and are harvested with the grain.

Ergot is favoured by cool wet weather at flowering, so open flowered varieties tend to be more susceptible. Sterile florets are also more likely to become infected as they remain open for longer periods. Ergot is best avoided by planting clean seed. The maximum tolerance level for ergots in seed is three pieces of ergot /500 g.

In the field, burying the ergots to a depth greater than 4 cm will stop them germinating the following year. Ploughing affected fields is an effective way to bury ergots. Avoid minimal cultivation techniques as this encourages problems next season. Whatever cultivations you carry out, be aware that mature grass in headlands, set aside, road verges etc. will act as a source of spores for crops when they are in flower.

Further Information

Ergot - What it is and How to Prevent it

CropCast - Ergot

Septoria leaf blotch symptoms on a flag leaf of wheat where it can reduce yield by 5-10% even in treated crops

Septoria tritici

Septoria tritici is currently the major disease in wheat. Although more resistant varieties, including Robigus have recently been added to the HGCA Recommended List, many varieties remain susceptible, including Consort. Issues concerning fungicide resistance have made it more of a challenge to manage in susceptible varieties.

About the Disease

Septoria tritici is currently the major disease in wheat. Although more resistant varieties, including Robigus have recently been added to the HGCA Recommended List, many varieties remain susceptible, including Consort. Issues concerning fungicide resistance have made it more of a challenge to manage in susceptible varieties. Septoria tritici can occur at any time during the growing season. It causes the most damage to yield if it attacks the upper leaves, in particular the flag leaf.

Weather conditions which suit the spread of Septoria tritici spores from the bottom of the crop to the upper leaves are wet and windy. Spores ooze from affected lower leaves and are spalshed up the plant in heavy rain. Dew and wind can also chieve the same effect. Crop canopy can play a role in spreading the disease. Short crops or crops wehre leaf layers overlap make it easier for the disease to spread. Wet or windy weather conditions at flag leaf emergence are therefore high risk for disease spread.

Further Information

Septoria – Still Much to Learn

Eyespot has been surprisingly common in spring barley crops over the last few seasons

Common Eyespot

About the Disease

Common eyespot is a fungal disease which attacks the stems of winter cereals. Winter wheat is affected most, but winter barley can also be affected. Spring crops and winter oats are not so badly affected by this disease. The disease causes lesions around the stem after flowering, which affect the uptake of water and nutrients into the developing grains. They also weaken the stem and most yield loss occurs when crops lodge.

The fungus can overwinter in trash, but it can also produce wind-blown spores. Early sown wheat crops (i.e. August and early September) are most at risk. Crops grown under minimum tillage cultivations are at lower risk than under ploughing. Some varieties have good resistance, but there is also a yield penalty when they are grown. New varieties with disease resistance but no yield penalty are expected soon.

There are two species of eyespot, but they are still known as the W and R types. The R type is now common in the UK, having taken over from the W type, which was common in the 1980’s. The R type develops later in the season and is more difficult to control with fungicides. Diagnostics can help determine the presence of both species. The presence of eyespot only forms part of a risk assessment, however. Presence of disease in the early spring cannot always be linked to disease severity at the end of the season.

Fusarium

Fusarium (Microdochium nivale) can have a big impact on the emergence of crops. It is a seed-borne disease which affects winter-sown cereals. Wheat is affected most, followed by oats then barley.

About the Disease

Fusarium (Microdochium nivale) can have a big impact on the emergence of crops. It is a seed-borne disease which affects winter-sown cereals. Wheat is affected most, followed by oats then barley. If the seed is heavily contaminated with the fungus, and seed is sown in cold and wet conditions, the impact on germination can be severe.

The disease can contaminate the grain during the period up to harvest when conditions may be cool and wet. Some fungicides applied to the head may reduce levels on the grain, but resistance to strobilurin fungicides is now widespread. At harvest, the seed may have high levels of contamination. Seed sown in cold and wet seed-beds may be slow to emerge. These conditions are also ideal for the fungus to germinate and attack the seedlings. This can have a major impact on crop establishment.

The two fungi responsible for causing Microdochium seedling blight in wheat and barley, Microdochium nivale and Microdochium majus, have become more prevalent over the last two years. Microdochium nivale and Microdochium majus are fungi which will colonise the heads of cereals in cool wet summers. These fungi are primarily a threat to winter wheat seed since they can reduce germination and cause a seedling blight in winter wheat. They are not known to produce mycotoxins, unlike other fungi known as Fusariums which can be present on cereals.

Further Information

Managing the Risk of Ear Diseases in Cereals

Diseases of Wheat

For the latest updates and information on crops and soils, subscribe to our Crops & Soils Newsletter.

You can also visit our archive for Crop Updates here.

General Information

Keeping a Lid on Winter Wheat Disease Risks

Spotlight on Manganese Deficiency in Spring Cereals

**Leaf Stripe (Cephalosporium)**

Yellow Rust

Further Information

Ergot

Further Information

Septoria tritici

Further Information

Common Eyespot

Fusarium

Further Information

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Diseases of Wheat

For the latest updates and information on crops and soils, subscribe to our Crops & Soils Newsletter.

You can also visit our archive for Crop Updates here.

General Information

Further Information

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Integrated Land Management Plans

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