Farm Focus: Fire Blight in the Apples


As we are all rejoicing over the arrival of our cherries, and though slim, apricots, we are at the same time lamenting about the discovery of extensive damage to our apple trees from fire blight.   


Fire blight is the result of an infection caused by the bacterium, Erwinia amylovora which can overwinter on a trees woody portions.  If conditions in the spring are warm and moist, as they were in the early spring this year when we were experienced a week of dewy mornings which turned into 80 degree days, the bacterium becomes highly activated and multiplies. 

Rain and insects move the bacterium from the woody portions onto the more tender and easily infected portions of the tree such as new shoots and flowers. Even if only one blossom in the orchard becomes infected, many more are likely to become so because bees act as vectors for spreading the bacterium during bloom. 

The infected flowers and surrounding shoots wilt and turn brown as a result of infection.  Our tree team is now busy in the orchard working to remove infected flowers and shoots in order minimize the damage to our trees and our fall crop.  By removing the infected portions we are able to save fruit that has formed on the tree and which has not yet been infected.  If we don't remove the diseased tissue from the tree, the bacteria would eventually work its way down the branches which hold the fruit. Healthy fruit will become infected and then the bacterium would continue to travel into scaffold branches and on into the trunk, killing the tree. 

Our crew can't use pruning shears to cut away the diseased tissue making the work more laborious.  One cut using the shears will place the bacterium onto the shears and infect any other part of the tree the shears cut.  So, our crew is going through each and every tree and removing the diseased portions by hand. We only have four acres of apple trees so our crew of 15 should be able to remove all of the infected tissue in about four days.

The good news in all of this is that we caught the fire blight early enough to save our crop and our trees.  Though we will likely see reduced harvest volume this fall, we can still look forward to biting into our crisp and sweet-tart Pink Lady apples.