A NEW EXPERIMENTAL DESIGN FOR TESTING CONTROL AGENTS FOR FIRE BLIGHT ON BLOSSOMS UNDER NEARLY NATURAL CONDITIONS

An experimental field design was developed which allowed the testing of control agents for fire blight under nearly natural conditions of infection.
Single plots consisted of at least six trees.
They were replicated four times and randomly distributed.
One tree in each plot was artificially inoculated by spraying a bacterial suspension of Erwinia amylovora during full bloom.
The trees left uninoculated were secondarily infected by natural means, such as wind, rain, and insects.
The directly inoculated and secondary infected trees were evaluated separately.
The compounds tested were; biological control agents, proposed inducers of systemic acquired resistance, and bactericides.
The incidence of infected blossom clusters was lower in the secondary infected trees, and resembled the incidence of infection under natural conditions.
The efficacies of the tested compounds, including the reference product streptomycin, were mostly higher in secondary than in directly inoculated trees.
We believe that the higher efficacies in secondary infected trees resemble closely natural infection conditions.
Nevertheless, none of the agents tested was an alternative to streptomycin.

IX International Workshop on Fire Blight

E. Moltmann, A. Fried, W. Jelkmann

Erwinia amylovora, apple, pear, biological control, inducers of systemic acquired resistance, bactericides, antibiotics

https://doi.org/10.17660/ActaHortic.2002.590.45