Published online by Cambridge University Press: 12 June 2017
Paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) at 1.1 and 2.2 kg/ha and paraquat + dinoseb (2-sec-butyl-4,6-dinitrophenol) at 1.1 + 0.7 kg/ha controlled redroot pigweed (Amaranthus retroflexus L.) and barnyardgrass [Echinochloa crus-galli (L.) Beauv.] in hops (Humulus lupulus L. ‘Yakima Cluster’) without reducing hop yield or the alpha and beta acid content of the hop cones. Three applications at about 3-week intervals were required to control weeds until harvest. Two applications controlled hop sucker growth. Paraquat at more than 0.6 kg/ha in the third application caused excessive reduction in hop sucker growth.