The population dynamics of Brachycaudus schwartzi aphids on peach orchards and Brachycaudus prunicola on plum orchards were detected in the region of Plovdiv during 2014. The former species had not previously been reported in Bulgaria, and the latter is poorly studied. The distribution of the two species in southern Bulgaria was studied in July and August. Both species were widespread and were found in most of the areas examined, with the exception of Haskovo, Yambol, Kardzhali and the southern part of the region of Bourgas. Br. prunicola occurred in the orchards till September, but the aphid colonized only shoots at the base of the plum trees. It can be concluded that the species is not a primary pest on plums (Prunus domestica) despite its wide distribution. The population density of Br. schwartzi increased in the second half of the vegetation period in all peach orchards. The species could be considered as a pest of economic importance since it caused heavy deformations on the leaves and shoots. The control would be difficult because it coincides with the harvest.