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鈥?0 渭M,
with stronger effects at lo
wer, but still physiological, pH values. In vitro tests
with juglone and inoculated flo
wers of apple (
Malus domestica) sho
wed an efficacy of 67% in preventing infection. In t
wo 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 kno
wn for its allelopathic effect on plants,
was restricted to bro
wning of petals; later fruit russeting
was not observed. Juglone is a promising candidate for the development of a ne
w environmentally friendly plant protectant to replace the antibiotic streptomycin currently used in fire
blight control.
Keywords:
bactericides; blight+control&qsSearchArea=searchText">fire blight control; naphthoquinones; pesticide development; plant quinones