Potential yield losses caused by barley leaf rust and oat leaf and stem rust to South African barley and oat cultivars

Abstract

Puccinia hordei (leaf rust) on barley as well as Puccinia coronata f. sp. avenae and Puccinia graminis f. sp. avenae (leaf/crown and stem rust) on oats are important diseases of these respective crops in South Africa. Notwithstanding the regular occurrence of epidemics, recent crop loss data for these diseases are not available. In this study epidemics were created artificially while control plots were sprayed with fungicide. In the oat trial, yield losses of as high as 85% were recorded for leaf (crown) and stem rust while in the case of barley leaf rust losses of as much as 58% were recorded. Not only were yields influenced by disease but also quality. Hectolitre mass was reduced by as much as 45% in oat, while kernel plumpness of barley was reduced by up to 65% and percentage siftings was increased by as much as 590%. This study emphasises the importance and destructive nature of rust diseases on both crops. It also emphasises the importance of ongoing research aimed at finding solutions to control these diseases.

Keywords:

• Puccinia coronata
• Puccinia graminis f. sp. avenae
• Puccinia hordei