Source: NCSU COOPERATIVE EXTENSION, 5/25/21
 
First take a moment to enjoy the beauty of the ooze droplets on the 'Honeycrisp’ shoot above and then after you’re done admiring “nature” think about the millions or billions of sticky Erwinia amylovora cells ready to spread fire blight to other trees nearby. This photo was taken on our “pot lot” at MHCREC where we are growing 'Honeycrisp’ and 'Evercrisp’ in containers for research on ambrosia beetles and rapid apple decline. Keep in mind, this plot is fairly isolated from other apple trees and receives drip irrigation. We went to remove some trees from the pot lot last week and realized a local fire blight epidemic had broken out in the Honeycrisp. Sure, Honeycrisp are quite susceptible to fire blight, but I was puzzled as to the source of inoculum-especially since it has been relatively dry over the past few weeks. My grad student, Sean Gresham than reminded me that we had inoculated six of the hundred or so trees with fire blight last year as part of an ambrosia beetle study and more than likely overwintering populations from those infections were the source of the outbreak. A good but painful reminder for us to clean up any cankers in the winter and ensure that green tip applications of copper are made annually!

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