ISHS Acta Horticulturae 338: VI International Workshop on Fireblight
BIOLOGICAL CONTROL OF FIRE BLIGHT BY ERWINIA HERBICOLA: SURVIVAL OF APPLIED BACTERIA IN ORCHARD AND GLASSHOUSE TRIALS |
| Authors: | L.P. Kearns, C.N. Hale |
| Abstract:
Survival of applied E. herbicola 1087 (Eh1087), a naturally occurring E. herbicola isolate that is inhibitory to E. amylovora, was investigated on apple blossoms in the orchard and the glasshouse at three different application dates throughout flowering. Bioassays of E. herbicola control of fire blight disease on excised apple blossoms maintained in humidity chambers were conducted in conjunction with survival experiments. Applied Eh1087 on apple blossoms in the orchard (application rate 7 x 107 cfu/blossom) showed only a 10–40 % survival rate four days post application. However, applied E. herbicola populations still remained 400-to 800-fold higher than naturally epiphytic E. herbicola populations for at least ten days post application. In glasshouse conditions applied Eh1087 populations reached levels 10- to 30-fold higher than naturally epiphytic E. herbicola populations. Most efficient colonisation by Eh1087 was seen at mid-flowering application. At early and mid-blossom stages applied Eh1087 gave 70 % to 80 % protection from fire blight disease, while late blossom applications gave only a 36 % protection from disease. | |
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