Etiology of bronze leaf disease of Populus

Jason A. Smith, R. A. Blanchette, M. E. Ostry, N. A. Anderson

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Bronze leaf disease is a potentially destructive disorder of the Populus section of the genus Populus. The causal agent has been reported to be Apioplagiostoma populi (anamorph: Discula sp.). Based on etiological and symptomological studies, field observations of symptom development suggest that the pathogen moves systemically in the host. This was verified by graft experiments where symptoms progressed from the scion into the elongating stem. A bronze-pigmented vascular discoloration was observed in symptomatic leaves and branches. Dieback of affected stems also was common. Spore-trap studies elucidated the timing and necessary weather conditions of A. populi ascospore dispersal in relation to infection and symptom development. Exposure-tree experiments revealed that ascospores of A. populi are the primary inoculum and resulting infection causes distinctive disease symptoms on affected trees. Perithecia of A. populi were observed on overwintered symptomatic leaves, but were not observed on asymptomatic leaves. Acervular conidiomata were observed on symptomatic leaves during August and September. Although A. populi ascospores germinated in vitro, A. populi was not recovered from symptomatic tissue. Isolations from diseased leaves consistently yielded Epicoccum nigrum, but the role of this species is unclear. Inoculations of susceptible plants with E. nigrum conidia failed to reproduce symptoms, but inoculations with ascospores of A. populi produced symptoms typical of bronze leaf disease and Koch's postulates were performed.

Original languageEnglish (US)
Pages (from-to)462-469
Number of pages8
JournalPlant disease
Issue number5
StatePublished - 2002


  • Ascomycetes
  • Aspen
  • Diaporthales
  • Disease resistance
  • Leuce section
  • Systemic fungi


Dive into the research topics of 'Etiology of bronze leaf disease of Populus'. Together they form a unique fingerprint.

Cite this