Mature Uroleucon rudbeckiae are shiny, bright red with yellowish legs and black antennae. The siphunculi are less than 1.6 times as long as the cauda, with reticulation of small polygonal cells on at least the distal quarter of their length. The cauda is dull yellow or sometimes dark in colour. The body length of adult Uroleucon rudbeckiae is anywhere between 2.4 and 3.2mm.