Integration of Benzobicyclon (Rogue) into a Quizalofop-Resistant Rice System for Improved Weed Control and Reduced Selection for Resistance.

Resistance to quizalofop-p-ethyl is the newest herbicide tolerance technology in rice fields. This technology provides resistance to the herbicides Provisia® and Highcard™ and adds a new mode of action for weedy rice control to the rice weed control portfolio. However, using additional chemistries is essential to ensure the prolonged viability of this technology and avoid weed resistance. Therefore, this study evaluated how benzobicyclon (Rogue®) fits into a Max-Ace® rice system where Highcard is used for weedy rice (Oryza spp.) and barnyardgrass [Echinochloa crus-galli (L.) P. Beauv.] control. The experiment was conducted in 2022 in Stuttgart, Arkansas, and organized in a two-factor randomized complete block with a split-plot setup. The whole-plot factor was with or without benzobicyclon postflood (POSTF), and the sub-plot factor was herbicide programs: 1) no herbicide, 2) quizalofop sprayed at early postemergence (EP) and preflood (PREF), 3) quizalofop sprayed at EP and POSTF, 4) quizalofop sprayed at PREF, and 5) quizalofop sprayed at POSTF, respectively. Weedy rice and barnyardgrass control was visually rated 4 weeks after POSTF treatments. Rough rice yields were obtained at the end of the season. For both weeds evaluated, the lowest control levels were obtained when quizalofop was only sprayed POSTF without benzobicyclon. Barnyardgrass and weedy rice control were above 95% whenever repeated herbicide applications of quizalofop were present, independently of benzobicyclon. The lowest yield was obtained in the treatment with a single application of quizalofop POSTF. The highest yields were obtained when treatments included benzobicyclon POSTF, or when quizalofop was sprayed twice in the season without benzobicyclon. The alliance of Max-Ace rice systems with an alternative herbicide like benzobicyclon is a potent weed control option to reduce the development of herbicide resistance throughout the years. [ABSTRACT FROM AUTHOR]