Found these aphids on a plum tree. Only one side of the tree was infested - the western side, from top to bottom. There were none on the eastern side of the tree. The tree stayed that way until September, when they all disappeared. Also, any idea what that brown larval thing is? They too were scattered throughout the infested side. For the two months the tree was infested (only this one tree was infested) there were also hundreds of ladybugs feasting on the aphids - Asians, 7-spots and Western Blood Reds. A lot of flies, wasps and spiders that don't normally hang out on this particular tree also made frequent visits.