Bacteria and fungi cause the majority of crabapple diseases. Knowledge of these pests and selecting proper tree environments lead to healthy crabapples.
Readers asked for more crabapple information and here are the nuts and bolts of why crabapple diseases ruin even the most beautifully designed landscape.
The growing season of 2007 was a tough one for crabapples in New England. A warm and wet spring in New England caused infection in a lot of blossoms and newly emerging shoots. Photos at the end of my article Crabapple Diseases: Disease Knowledge and Proper Environment Lead to Healthy Trees
give some idea of what area crabapple trees looked like, and what kind of hazards they produced.
A culprit, other than weather in April, May and June, continues to be the abundance of neglected eating apple trees and crabapple trees growing wild, like around farmhouses and cellar holes. They may appear romantic in song, verse, paintings and photos, but they harbor bacterial and fungal diseases.
The 40-year-old, 30-foot-high pink-flowered crabapple tree that graces the small deck entrance into my kitchen was completely defoliated and all the fruit prematurely dropped. This was the worst I've ever seen it. It was so bad that despite the fact that I was constantly sweeping away masses of dead leaves and withered rotting fruit, my family could not use the space because it was so filthy!
Yes, there are many old trees around my neighborhood and property that harbor diseases. And no, I won't spray fungicide. That is time-consuming (requires many applications), expensive and not particularly healthy.
Fungicide applications do work relatively well. There were no diseases showing in the UMass (Amherst, MA) Cold Spring Orchard that is culturally well cared for and receives required timely fungicide applications.
I can only hope that my crabapple tree will be its usually lovely self during the 2008 growing season.
