Potent and specific bactericidal effect of juglone (5-hydroxy-1,4-naphthoquinone) on the fire blight pathogen Erwinia amylovora

J Agric Food Chem. 2012 Dec 12;60(49):12074-81. doi: 10.1021/jf303584r. Epub 2012 Nov 29.


A screening of plant quinones for inhibiting effects on the bacterial fire blight pathogen Erwinia amylovora was performed. The most active compound, juglone from walnuts, has a potent and specific bactericidal effect on E. amylovora and minimal inhibitory concentrations of only 2.5-10 μM, with stronger effects at lower, but still physiological, pH values. In vitro tests with juglone and inoculated flowers of apple (Malus domestica) showed an efficacy of 67% in preventing infection. In two years of field tests juglone had variable degrees of efficacy ranging from 40 to 82%, seemingly due to environmental conditions. A phytotoxic reaction to juglone, which is known for its allelopathic effect on plants, was restricted to browning of petals; later fruit russeting was not observed. Juglone is a promising candidate for the development of a new environmentally friendly plant protectant to replace the antibiotic streptomycin currently used in fire blight control.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Agrochemicals / pharmacology
  • Anti-Bacterial Agents / pharmacology
  • Drug Evaluation, Preclinical
  • Drug Stability
  • Erwinia amylovora / drug effects*
  • Erwinia amylovora / pathogenicity*
  • Flowers / drug effects
  • Flowers / microbiology
  • Germination / drug effects
  • Hydrogen-Ion Concentration
  • Malus / drug effects*
  • Malus / microbiology*
  • Microbial Sensitivity Tests
  • Naphthoquinones / pharmacology*
  • Plant Diseases / microbiology
  • Plant Diseases / prevention & control
  • Quinones / chemistry
  • Quinones / pharmacology
  • Toxicity Tests / methods


  • Agrochemicals
  • Anti-Bacterial Agents
  • Naphthoquinones
  • Quinones
  • juglone