PRODUCTS FROM PSEUDOMONADS FOR POSSIBLE CONTROL OF FIRE BLIGHT

In our search for compounds from Pseudomonas species that may be used for the control of fire blight disease in apple trees, we have obtained seven chemicals for further evaluation.
The chemical work was guided by a standard antibiotic style of bioassay where a zone of growth inhibition appeared around the site of application of compounds to agar plates overlayed with a culture of Erwinia amylovora. Bioactive chemicals were produced in liquid culture media, isolated from the medium, and then purified.
Structural data was then accumulated, thus providing in the first instance a firm indication of the structural class of compound, and in some cases a final chemical structure.
We have undertaken an initial assessment of the biological effectiveness of a number of these chemicals with an immature pear fruit assay, which measures the ability of an individual compound at preventing the development of fire blight symptoms on discs of pear fruit inoculated with 10⁶ cells/ml of E. amylovora. To date, these tests on compounds at an application rate of 50 μg per disc have revealed 2 compounds in particular that may be potentially useful, and several others that were ineffective in preventing the development of fire blight symptoms after 5 days.

VII International Workshop on Fire Blight

R.E. Mitchell, K.L. Ford, J.L. Vanneste

https://doi.org/10.17660/ActaHortic.1996.411.64