Semester of Graduation
Master of Science (MS)
Plant, Environmental, and Soil Sciences
A field study was conducted in 2017 and 2018 at the LSU Agricultural Center H. Rouse Caffey Rice Research Station (RRS) near Crowley, LA. to evaluate the influence of different adjuvants in overcoming the antagonism of quizalofop when mixed with bispyribac in Louisiana rice production. The antagonism of quizalofop mixed with bispyribac plus HCOC at 14 DAIT was overcome with a neutral interaction observed at 28 DAIT for barnyardgrass control with an observed control of 91%, compared with an expected control of 97%. The addition of COC, SNS or HCOC into a mixture of quizalofop plus bispyribac provided synergistic or neutral interactions at 14 and 28 DAIT for CL-111, CLXL-745, and red rice control.
A field study was conducted in 2017 and 2018 at RRS in 2017 and 2018 to evaluate the impact of reduced rates of halosulfuron on quizalofop activity in Louisiana rice production. At 28 DAIT, antagonism of quizalofop for barnyardgrass control was observed when mixed with halosulfuron plus thifensulfuron at 53 g ha-1 with an observed control of 89%, compared with an expected control of 98%; however, this antagonism was overcome at the same evaluation date with a neutral interaction for barnyardgrass control when quizalofop was mixed with halosulfuron plus thifensufluron at 34 g ha-1 with an observed control of 96%.
Two Field studies were conducted in 2018 at RRS to evaluate sequential applications of quizalofop applied on previously antagonized weeds from a quizalofop plus propanil mixture to determine the time needed between antagonism and a second application of quizalofop. Quizalofop mixed with propanil followed by a sequential application of quizalofop at 7, 14, and 21 DAIT controlled barnyardgrass with an observed visual value of 97 to 98%, compared with an expected control of 95 to 98%. However, the sequential treatment of quizalofop applied at 28 DAIT to antagonized barnyardgrass resulted in 71% control, compared with an expected control of 67%.
Webster, Lucas C., "Strategies to Overcome Antagonism of Quizalofop-p-ethyl when Applied in Mixture with Other Herbicides" (2019). LSU Master's Theses. 4898.