Skip to page content
USDA Forest Service

Research & Development Treesearch

Treesearch Home
About Treesearch
Contact Us
Research & Development
Forest Products Lab
International Institute of Tropical Forestry
Pacific Northwest
Pacific Southwest
Rocky Mountain
Southern Research Station
Help - We Participate  Government Made Easy

Global Forest Information Service

US Forest Service
P.O. Box 96090
Washington, D.C.

(202) 205-8333

You are here: Home / Search / Publication Information
Bookmark and Share

Publication Information

View PDF (1.4 MB)

Title: Etiology of bronze leaf disease of Populus

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

Date: 2002

Source: The American Phytopathological Society 86(5):462-469

Publication Series: Scientific Journal (JRNL)

Description: 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 (anarnorph: 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.

Keywords: Ascomycetes, aspen, Diaporthales, disease resistance, Leuce section, systemic fungi

Publication Notes:

  • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
  • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
  • This publication may be available in hard copy. Check the Northern Research Station web site to request a printed copy of this publication.
  • Our on-line publications are scanned and captured using Adobe Acrobat. During the capture process some typographical errors may occur. Please contact Sharon Hobrla, if you notice any errors which make this publication unusable.



Smith, Jason A.; Blanchette, R. A.; Ostry, M. E.; Anderson, N. A. 2002. Etiology of bronze leaf disease of Populus. The American Phytopathological Society 86(5):462-469


 [ Get Acrobat ]  Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility

USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.