most important control of fire blight in the orchard is through
acheived through vigilant cultural control. This bacteria is sneaky;
it will disappear for ten years and reappear as soon as you have
grown sure of its eradication.
pruning of all infected branches and shoots, as well as removal
of trees that are too damaged to be pruned, is very important.
This must be done each winter, without fail.
Supplemental nitrogen should be used only when the tree is visibly
stressed. New, growing shoots are good targets for infection,
and fertilizers can increase the duration of vegetative growth.
trees are more damaged by infections.
sprays before green tip may prevent bacteria from residing on
buds and bark.
sprays every 3 to 5 days during bloom, or as predicited by MaryBlyt,
will prevent infections and control recent infections. Antibiotic
sprays are not useful in controlling established infections.
sprays immediately following a trauma event (storms, hail, &
late frost) can be effective.
you have only a few strikes in the orchard, pruning the infected
tissue during the growing season can be cost effective. Make cuts
well before the infection and only at an internode. Leave four
inches of branch remaining before the internode when pruning to
allow any potential small cankers to be easily removed during