How to Prune Out Diseased Wood
The Shigo method cuts away diseased wood and ensures your plant won’t be reinfected
In pruning texts and articles you’ll often see references to the 3 D’s. This stands for dead, damaged, and diseased wood. All three types are harmful to your plant and should be removed. Diseased wood presents a particular challenge, because you only want to remove the branches and sections of plant that are infected. But you need to be sure you prune out all of the disease to ensure that none is left behind to wreak havoc on your plant. The Shigo method shows you how to do this quickly and effectively.
Locate the branches that are infected and showing signs of disease. First, make an undercut at the halfway point of a larger branch. The cut should be roughly the depth of your saw’s teeth.
Saw down through the top of the branch with an overcut to meet up with your initial undercut. You’re aiming to take some of the weight off the branch in order to remove it without splitting or peeling. This is especially important with thin-barked species.
Continue down the infected (not cut in half) branch to the branch collar, and again make an undercut.
Make another overcut, and once again meet up with the undercut. Make your cut cleanly right against the branch collar. This ensures healing will take place quickly.
Be sure there are no signs of disease within the wood that is left behind.
Sanitize your pruning tools to prevent passing the disease to future pruning projects.
In this video supplement to the 2013 edition of Common Sense Pest Control from Taunton Press, Steven Ash demonstrates this integrated pest management (IPM) pruning cut.