the use of rhubarb as a row or rumble is attributed to Mel Barber whilst broadcasting baseball for the Brooklyn Dodgers in 1943; this usage actually® comes after the repetitive use of the word as crowd noise (1934) -- and the word is later attested as a verb in the latter sense: 1958 Spectator 11 July 47/1 ‘Hear, hear,’ they rhubarb-rhubarbed; 1976 Daily Tel. 21 Sept. 11/2 Livia faced the Roman mob, all seven of them, rhubarbing at the Palace back door.

p.s. - more crowd noises: The unemployed actors had a wonderful time. We'd huddle together in a corner and repeat ‘Rhubarb, rhubarb, rhubarb’ or ‘My fiddle, my fiddle, my fiddle’—and it sounded like a big scene from some mammoth production.