Bacterial blight caused by Pseudomonas syringae pv. syringae shown to be an important disease of field pea in south eastern Australia

Abstract

P. syringae pv. syringae was shown to be the cause of bacterial blight in 40% of field pea crops showing symptoms of bacterial blight during 2005 compared to 47.5% caused by P. syringae pv. pisi and the 12.5% of crops infected by both pathovars. A replicated field experiment conducted in the presence of stubble infected with P. syringae pv. syringae quantified yield losses in commercial cultivars due to this pathovar. Within this study field pea cultivars could be divided into two groups based on resistance or susceptibility to bacterial blight caused by P. syringae pv. syringae. The average yield loss in the resistant cultivars in the presence of infected field pea stubble was 23%, whereas in the susceptible cultivars the yield loss was 75%. In one cultivar a yield loss of 94% was measured. Variability between cultivars and breeding lines in their responses indicates potential for breeders to develop P. syringae pv. syringae resistant cultivars. Studies into the survival of P. syringae pv. syringae on infected field pea stubble showed that the pathogen could not be recovered after 34 weeks.