June 27, 2017
A pretty strong storm with high winds and hail just blew through East Montpelier and Calais; my colleague up in South Burlington reports barely a puff of wind up there. The point here is that hail may have affected area orchards, but as is usually the case, was highly variable in location and severity. Aside from the crop damage implications, which require a call to your crop insurance agent within 24 hours, there is the potential for fire blight (FB) infection to be spread to damaged fruit and tissues.
However, there are three things that need to be present for trauma-induced FB to occur: 1) active FB infections in the orchard; 2) hail and/or high winds that could cause open wounds to plant tissues, and; 3) sufficient heat for bacteria to multiply and infect. If you have no FB in your orchard or in the immediate vicinity, there is no need to treat. If you missed the storms, again, no need to treat. And the weather has been relatively cool but there have been sufficient warm spells and a warmup is expected on Friday, so that is not a mitigating factor.
I have been scouting some orchards in the state and have seen sporadic FB, including in our own UVM orchards. Still, even if sporadic and you were affected by the storm (and I don’t mean rain and a little wind, I mean hail and ‘whip the trees around’ wind) treatment is justified. By now growers should know the FB status in your orchards. If there is any question, consider treating. But if there is no FB, there is no need to spray.
Materials need to go on within 24 hours of a trauma event. Streptomycin is the gold standard and should be the only material considered if you aren’t certified organic. If organic, Serenade or Cueva + Double Nickel may be effective but I am not guaranteeing excellent results.
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