Characterization of Fusarium spp. associated with lupin in central Alberta, Canada

Abstract

Narrow-leaved lupin (Lupinus angustifolius) is being assessed as a potential pulse crop for western Canada. However, root rot caused by Fusarium spp. is a potentially important disease of lupin in the region. The aim of this study was to identify the Fusarium spp. that aggressively attack lupin in central Alberta. Fusarium isolates were recovered from diseased lupin plants in 2005 and 2006. Fusarium avenaceum was the most frequently recovered species, followed by F. oxysporum, F. solani, and F. acuminatum. Inoculation of lupin with F. avenaceum produced severe root rot symptoms in a greenhouse assay, although there was a wide range in aggressiveness among isolates within this species. Although lupin roots were often colonized by other Fusarium species in addition to F. avenaceum, these other species were shown to be non-pathogenic or only weakly pathogenic. Co-inoculation studies indicated that the other Fusarium species that are associated with lupin roots do not contribute to a disease complex, so we conclude that F. avenaceum is the dominant pathogen responsible for root rot on lupin in central Alberta. The host range of F. avenaceum isolates from lupin included a wide range of pulse and oilseed crops grown in the region, so crop rotation is unlikely to have an important impact on management of this potentially destructive pathogen.