Sharp Eyespot of Wheat caused by Corticium (Rhizoctonia) Solani

Abstract

EYESPOT of wheat caused by Cercosporella herpotrichoides is widespread in East Anglia, where it causes considerable loss in yield¹. Typical symptoms of the disease are oval brown-bordered lesions on the straws near soil level. Similar, but less regular, lesions caused by another fungus have been recognized at Rothamsted as a different disease since 1935. This was described in Holland and figured by Oort², who called it sharp eyespot but did not identify the causal organism. Sprague^3,4 found a Rhizoctonia causing similar symptoms on wheat in Oregon. Blair⁵, working with Rhizoctonia Solani, found that some Canadian strains when inoculated into wheat caused a stem girdling injury the photographs of which resemble those of sharp eyespot. Neither worker identified the lesions caused by Rhizoctonia as the sharp eyespot described by Oort.