EPPO Global Database

EPPO Reporting Service no. 05 - 1991 Num. article: 1991/05

Streptomycin resistance of Erwinia amylovora in Washington state (US)

In Washington state (US) 138 pathogenic strains of Erwinia amylovora out of 44 pear orchards were sampled to evaluate their sensitivity to streptomycin, oxytetracycline and copper.
A total of 98 strains sampled from 38 orchards were resistant to streptomycin. Streptomycin-resistant strains were even sampled from orchards with no recent history of streptomycin usage.
All strains were susceptible to high dosages of oxytetracycline and copper (CuSO4), however, all collected E. amylovora strains developed spontaneous mutants with a low level tolerance to the CuSO4 treatment. This might indicate a potential of E. amylovora to build up a resistance against copper compounds.


Loper, J.E.; Henkels, M.D.; Roberts, R.G.; Grove, G.G.; Willett, M.J.; Smith, T.J. (1991) Evaluation of streptomycin, oxytetracycline, and copper resistance of Erwinia amylovora isolated from pear orchards in Washington State.
Plant Disease 75, 287-290.