Sharp Eyespot as a Severe Disease of Oats

Abstract

SHARP eyespot of wheat¹, caused by Corticium (Rhizoctonia) Solani, is a common disease; but the lesions on leaf sheaths and straws are usually superficial, and there is no evidence that it is of economic importance. Hitherto, it does not appear to have been described on other cereals in Great Britain, though Oört² shows a photograph of it on rye in Holland, and Sprague records it on barley³ and on oats⁴ in America. This year a crop of oats has been found in Bedfordshire with many plants severely attacked by a Rhizoctonia resembling that obtained from sharp eyespot in wheat. The lesions in oats resemble those in wheat; but the fungus penetrates deeply into the tissues of leaf sheaths and straws, rotting the shoots. The disease is evidently serious; but the loss cannot be estimated because another parasite, the eelworm Heterodora major, is attacking the roots and reducing growth of the crop. Many barley and a few wheat plants are scattered among the oats and some show typical superficial sharp eyespot lesions; the vigorous growth of the wheat and barley does not seem to be affected, and contrasts vividly with that of the oats.