Abstract
A root and basal stem rot disease has occurred in narrowleaf lupin (Lupinus angustifolius) in New South Wales (NSW) since at least 1993. Leaves of affected plants wilt, become chlorotic and fall. Symptom progression is acropetal and plants die within a few days. Taproots are completely rotted with a dark-brown to black sunken lesion frequently extending up the stem. Symptoms develop usually at pod filling. In 1999, L. angustifolius cv. Wonga growing in a field trial at Temora, NSW was severely affected by this disease. An undescribed species of Phytophthora (DAR 75401) was consistently isolated from all symptomatic plants. The isolates were characterized by nonpapillate, ovoid to obpyriform sporangia, nearly spherical oogonia with markedly aplerotic oospores, and amphigynous antheridia. Many of these characters are shared with Phytophthora vignae, P. erythroseptica, and the P. megasperma group. However, this isolate also differs significantly from each of these species, and is not adequately encompassed by any species described by Erwin & Ribeiro (1996). The isolated oomycete was inoculated into pasteurized potting soil and the pots sown with L. angustifolius cv. Merrit. The plants were grown in a screen house under field temperatures, where they developed typical disease symptoms at flowering to early pod set. Noninoculated controls did not develop disease. The pathogenic isolate was re-isolated from all diseased plants. A survey of narrowleaf lupins in 2000 showed that this disease was widely distributed in NSW, and a Phytophthora sp. identical to the Temora isolates was consistently isolated. Trapero-Casas et al. (2000) reported a similar disease on three lupin species in Spain caused by P. erythroseptica. Brittlebank & Fish (1927) reported P. cryptogea associated with root rot of Lupinus sp. in an Australian garden, but this is the first report of Phytophthora causing a widespread disease of narrowleaf lupin in Australia.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
