BIOCONTROL OF FIRE BLIGHT WITH THE BACTERIAL ANTAGONIST RHANELLA AQUATILIS RA39 IN COMBINATION WITH AROMATIC COMPOUNDS

The bacterial strain Ra39 of Rahnella aquatilis significantly reduced fire blight incidence on blossom in the field.
However, efficacy of Ra39 in reducing the disease was lower than that of streptomycin and was not high enough for commercial purposes.
To increase the efficiency of control, Ra39 was combined with different aromatic compounds, which inhibited the fire blight pathogen in vitro.
In the laboratory, on petri dishes Ra 39, in contrast to Erwinia amylovora, showed no sensitivity to aromatic compounds like benzoate and vanillate and was able to degrade these compounds.
In the field, a combination of Ra 39 and benzoate reduced fire blight on blossoms to levels (68%) nearly similar to that of streptomycin (77%) and higher to that obtained with Ra39 by itself.
In conclusion, the combination of Ra39 and benzoate represents an effective alternative to chemicals for control of fire blight.

X International Workshop on Fire Blight

W. Zeller, P. Laux

Erwinia amylovora, apple, antagonistic bacterium, Na-Benzoate, disease control efficacy

https://doi.org/10.17660/ActaHortic.2006.704.50