Occurrence of maize rust, Puccinia sorghi, in England

Abstract

Possible methods of initiation of outbreaks of Puccinia sorghi Schw. in England have been investigated. Urediniospores did not survive winter to initiate infection in the new crop. The influence of temperature and humidity on the viability of urediniosopores has been investigated. Combinations of low temperatures and humidities were found to be ideal for long survival of urediniospores. Teliospores, favoured by low humidities for survival, were capable of withstanding the winter of 1975/6. These infected the alternate host, Oxalis corniculata L., which is widely distributed in the British Isles, at the time when the new crop of maize was being sown. Although O. corniculata may play an important role in the epidemiology, the role of some grasses, which harbour the uredinial stage, has been found to be relatively unimportant. The possibility of migration of urediniospores from other countries cannot be ruled out.