Ninety-nine percent of problems that arise after pruning are due to improper techniques, rather than a lack of dressing applied to the wound.

Cuts that are made too close to the main trunk (called a flush cut) are not good, nor are cuts that leave too large a stub.

All pruning cuts, on large or small trees, should be made just outside what is called the branch collar in order that the tree or shrub can swiftly seal itself from problems.
This process is called compartmentalization, and is a physiological response that most woody plants have to injury. Using a pruning paint or dressing can impede this natural phenomenon.

Compartmentalization can only occur if the branch collar is not removed or cut into. I'm linking you to a small slide show with lots of information in the form of images. You'll be able to identify branch collars on just about anything after you review it. Just click on the directional arrow to view the whole presentation.

Also, be sure to sterilize your pruners, loppers, or hand saw prior to use. We can transfer pathogens via our hands, gloves, clothes, too. I prefer straight rubbing alcohol to bleach.

Air borne pathogens, by the way, can enter a tree through any kind of wound...even those that may seem insignificant.

Here is a link that might be useful: Removing branches

Rhizo as always has given you excellent advice and the link is exceptional. I would only add a little caveat that 1:10 or 1:20 bleach to water solution is more effective in killing pathogens. Rhizo, we're not even using rubbing alcohol in nursing anymore, to cleanse an injection or IV site. We have known for years that all rubbing alcohol does is move the pathogens around. It doesn't really kill much of anything. You're much better off using a bleach solution. This was also recommended by Tom Shea at my Citrus class are UC Riverside Extension. May I ask why you prefer rubbing alcohol?

Patty S.

I've never had a pruning cut become infected. And I don't disinfect or coat the cut surface. I've also never seen a graft or budding site become infected. Don't say it can't happen and I'm in a generally dry climate so YMMV.