I have a friend who swears that these areas on the branches are the start of black knot on my Prune plum but they don't look like some pictures I have seen elsewhere on the web. Is this really the beginning of the problem or is it something else? It looks to me like the bark has just peeled away around the location where a twig once was?? Thanks Plum-1 Plum-2 Plum-3 Plum-4 PS Sorry for the slightly blurry pics, not quite sure how to focus with my husbands digital camera.:o( Anne