I'm hoping someone can help me understand collar rot. At a recent grafting workshop I grafted a Grimes Golden onto MM 111. I have learned that the Grimes is susceptible to collar rot. Here is my question. Collar rot affects the root system and bottom of the tree, and hence the rootstock (in this case 111). So when it is said that Grimes is susceptible to it, does this simply mean that if the rootstock gets collar rot, it will inevitably also travel up and affect the Grimes scion? And if this is so, does this mean that the chance a given grafted Grimes tree will get collar rot is no greater than the chance that any MM 111 rootstock will get it? Any information would be much appreciated.