The thin, blunt section of the handle of a grafting knife which is used to hold the host tree’s bark open while inserting the cutting. Generally fixed and the head end of the handle (as pictured), occasionally it is a folding “blade”. Alternately, a dull, beveled “horn” near the tip of the knife’s blade, for the same purpose.

A Budding Blade with spud “horn” hear the blade’s tip.