Thus, until we have more experience with Messenger, it should be used only as a means of adding extra protection to existing streptomycin programs. Messenger should not be used as a substitute for streptomycin. Minimizing shoot blight damage begins by pruning out infected limbs as soon as symptoms are detected and before extensive necrosis develops. When pruning out active cankers, cuts should be made at least 12 inches below symptoms. Growers should use management systems that promote early cessation of tree growth without adversely affecting tree vigor.
Excessive vigor is an important component of orchard risk for fire blight.
When tree growth continues past mid summer, the likelihood that late season or trauma blight infections will overwinter increases. Nitrogen fertilizer should be applied based on foliar analysis. In young blocks, it is possible to use Apogee as a means to terminate growth and possibly minimize the damage due to fire blight. The thoughts behind this approach will be featured in an article next week. After midsummer, when trees have hardened off for the season, streptomycin protection following trauma events may be unnecessary because trees are thought to be fairly resistant to fire blight after tree growth stops for the season.