Ceratobasidium cereal (Rhizoctonia ceralis)
Fungus
Wheat, barley, oats rye, triticale, grasses.
Pale lesions with distinct dark borders appear on the stem up to 30cm above the soil surface. A purplish-brown fungal mass may develop in the lesion. If the stem is cut open, fruiting bodies, sclerotia, can sometimes be found inside.
Some strains of sharp eyespot can infect the roots leading to weak straggly plants usually appearing in discrete patches and often exhibit a purple discolouration. The plants tend to recover with secondary root growth appearing in the spring.
Early infections and high sharp eyespot disease pressure can lead to `white-heads` and lodging.
The source of infection is mycelium in the soil. Infection and development is favoured by dry, cool autumns and springs.
Slow plant growth through the winter and spring, light soils.
Common in the UK and leads to loss of yield, shrivelled grain and increased lodging risk. Yield loss is lower than with true eyespot.
• Timely application of fungicide
• Break crops in the rotation can reduce the level of inoculum although the wide range of volunteer hosts limits the effectiveness of this technique.
Sharp eyespot can be differentiated from true eyespot by:-
i) More sharply defined lesions
ii) Fungal mass can be scraped off
iii) Multiple lesions – up to 30cms up the stem
iv) Sclerotia in stem
Sharp eyespot on wheat stemFind out more information on the key disease threats to your cereal crop. For each disease you will find out the importance of the disease in terms of potential yield penalty, how to identify the disease in its early stages and our advice on the best control strategies.