Plum pox show no symptoms on leaves or fruit. Not all infection in "Prunus" are characterized by a ring symptom on leaves. Several cultivars show yellowing line patterns and blotches, or necrotic ring symptoms on expanded leaves. Leaf distortion has also been observed. Infected fruit can develop yellow rings or blotches, or brown rings, and some plum and apricot fruit can be severely deformed and bumpy. The seed of many infected apricots and some plums show rings. Many non-"Prunus" species, in at least nine plant families, have been infected artificially with one or more strains of the plum pox virus, and in
Plum cake many who ate a light style of plum cake with tea, into which he would dip the cake, which he described as bun-like with currants "dotted here and there". Elizabeth David wrote that "Christmas mincemeat and Christmas plum pudding and cake are all such typical examples of the English fondness for spiced fruit mixtures that it seems almost unnecessary to include recipes for them ..." Plum cakes were raised by whipping air into the cake batter, rather than by the use of yeast. A range of plum cakes and puddings were published in the popular Book of Household Management (published