Written by Tianna DuPont, WSU Extension, Tree Fruit Specialist. April 10, 2017.

With the large number of fire blight infections last year plan as if fire blight is in your neighborhood this year. Time will tell in the next week or so if conditions will be favorable during bloom. But I think this year it is important to be prepared for high pressure. Using biologicals as part of your integrated program for conventional or organic is an important tool to help reduce the build up of the pathogen in flowers. Consider using Blossom Protect (Aureobasidium pullulans, yeast) or Bloomtime biological (less russet risk). When using Blossom Protect make sure to:

Tips for use of Blossom Protect

  • Apply to every row. Research has found better colonization of flowers by the yeast strains when it has been spray applied to the whole tree. That is, yeasts that colonize pome flowers do not appear to spread flower-to-flower as well as bacteria.
  • Apply early. Applications during early bloom (30 to 70%) allow sufficient time for the yeast population to grow, which leads to more effective control.
  • Use buffer. Blossom protect applications with the companion material, Buffer Protect, have shown significantly better control than with Blossom Protect alone.
  • Re-apply after lime-sulfur. Lime sulfur applications are both anti-bacterial and anti-yeast and will affect the populations of an applied biological. Reapplication of the biological after lime sulfur treatment is necessary, or wait to use Blossom Protect until after lime sulfur.

For details on Fire Blight Management

Tianna DuPontTianna DuPont,

Tree Fruit Extension Specialist

(509) 663-8181 ext 211

(509) 713-5346