Combined effects of elevated CO2 and natural climatic variation on leaf spot diseases of redbud and sweetgum trees

Andrew J. McElrone, Jason G. Hamilton, Anthony J. Krafnick, Mihai Aldea, Rachel G. Knepp, Evan H. DeLucia

Research output: Contribution to journalArticlepeer-review


Atmospheric CO2 concentrations are predicted to double within the next century and alter climate regimes, yet the extent that these changes will affect plant diseases remains unclear. In this study conducted over five years, we assessed how elevated CO2 and interannual climatic variability affect Cercospora leaf spot diseases of two deciduous trees. Climatic data varied considerably between the five years and altered disease expression. Disease incidence and severity for both species were greater in years with above average rainfall. In years with above average temperatures, disease incidence for Liquidambar styraciflua was decreased significantly. When significant changes did occur, disease incidence and severity always increased under elevated CO2. Chlorophyll fluorescence imaging of leaves revealed that any visible increase in disease severity induced by elevated CO2 was mitigated by higher photosynthetic efficiency in the remaining undamaged leaf tissue and in a halo surrounding lesions.

Original languageEnglish (US)
Pages (from-to)108-114
Number of pages7
JournalEnvironmental Pollution
Issue number1
StatePublished - Jan 2010


  • Cercis canadensis
  • Cercospora leaf spot
  • Climate change
  • Duke FACE
  • Free-air CO enrichment
  • Fungal plant pathogen
  • Liquidambar styraciflua
  • Plant disease
  • Plant-pathogen interactions

ASJC Scopus subject areas

  • Toxicology
  • Pollution
  • Health, Toxicology and Mutagenesis


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