SURVIVAL OF ERWINIA AMYLOVORA ON APPLE FLOWERS TREATED WITH ANTIBACTERIAL IMINOPYRROLIDINE COMPOUNDS

Two natural compounds (IMP-Val and IMP-Thr) consisting of an amino acid residue conjugated to an iminopyrrolidine carboxylic acid structure (IMP), and a synthetic derivative (IMP-Leu), which inhibit the growth of Erwinia amylovora on agar plates, were tested for their ability to inhibit E. amylovora on apple and pear flowers. Populations of E. amylovora on flowers treated before inoculation with one of these three compounds at either 100 ppm or 200 ppm were found similar to that growing on flowers treated with water and higher than those found on streptomycin-treated flowers. E. amylovora recovered from flowers treated with either IMP-Leu or IMP-Thr was still pathogenic and was still inhibited by either IMP-Leu or IMP-Thr on agar plates with minimal medium. The presence of yeast extracts in the minimal medium prevented inhibition of E. amylovora on agar plates by all IMP-derivatives tested. This suggests that the presence some compounds, presently unknown, on apple and pear flowers of prevents the IMP derivatives from inhibiting E. amylovora.