USE OF ANTIBIOTICS TO CONTROL FIRE BLIGHT IN FRANCE: ENVIRONMENTAL HAZARDS AND ESTABLISHED LEGISLATION

Several unexpected effects of the use of antibiotics to control bacterial plant diseases of fruit trees were examined: The man who performed the treatment by spraying streptomycin in pear and apple orchards during two years consecutively did not show any sensitivity to the antibiotic and no modification in his intestinal microflora was recovered.
The control of the persistence of streptomycin on pear and apple trees showed that no residues were detected on leaves and fruits four weeks after the last treatment.
The effects of repeated streptomycin sprays on leaf microflora on pear trees involved an increase of pre-existing streptomycin-resistant bacterial populations.
The treatments did not select any R-plasmid in Enterobacteriacae although a streptomycin and oxytetracyclin resistant carried plasmid has been detected in one isolate of Erwinia herbicola. The transfer by conjugation of RP4 plasmid occurred between a pathogenic bacteria of Hazelnut (Xanthomonas campestris pv. corylina) and an epiphytic bacteria (E. herbicola) in woody tissues and on leaf surfaces of Hazelnut (Corylus avellana L.). An investigation of R plasmid among epiphytic Enterobacteriacae showed they were rare, only two R plasmids among more than three hundred streptomycin resistant isolates were recovered.
Using partly this study legislation was established to control the unexpected effect of antibiotics as the use of the flumequine was permitted in France in 1986.

IV International Workshop on Fire Blight

C. Manceau, L. Gardan, J.P. Paulin

https://doi.org/10.17660/ActaHortic.1987.217.33