Interactions Observed with Clomazone plus Pendimethalin when Mixed with Postemergence Rice Herbicides
Semester of Graduation
Master of Agriculture (MAgr)
Plant, Environmental Management, and Soil Sciences
A study was conducted at the Louisiana State University Agricultural Center’s H. Rouse Caffey Rice Research Station (RRS) in 2017 and 2018 to evaluate whether the pre-packaged mixture of clomazone plus pendimethalin should be applied delayed preemergence (DPRE) or postemergence (POST) within a herbicide residual overlay with saflufenacil, clomazone, or quinclorac. POST applications also included penoxsulam or halosulfuron in combination with the second residual application. No differences were observed with barnyardgrass control at 14 DAT across all treatments with 92 to 98% control. At 42 DAT, barnyardgrass treated with either clomazone plus pendimethalin applied at either timingin combination with either clomazone or quinclorac applied POST controlled barnyardgrass 95 to 96%. However, when saflufenacil was applied PRE regardless of the POST herbicide or when saflufenacil was applied POST with halosulfuron resulted in reduced barnyardgrass control, 78 to 81%, compared with control with all other residual combinations, 95 to 96%. Yellow nutsedge and rice flatsedge increased when treated with halosulfuron compared with penoxsulam across all evaluation dates.
A study was conducted at RRS in 2017 and 2018 to evaluate the interaction between various rates of clomazone plus pendimethalin mixed with various rates of propanil. A synergistic response occurred when barnyardgrass was treated with all herbicide mixtures at 56 DAT. Yellow nutsedge control when treated with all herbicide mixtures was neutral except when treated with 1145 g ha-1 of clomazone plus pendimethalin mixed with 4485 g ha-1 of propanil. Rice flatsedge control at 28 DAT produced neutral interactions for all herbicide mixtures.
A study was conducted in 2017 and 2018 at RRS to evaluate the activity of quizalofop applied independently or in a mixture with clomazone, pendimethalin, clomazone plus pendimethalin, and a pre-packaged mixture of clomazone plus pendimethalin. Even though antagonism occurred at 7 DAT for all mixtures except when pendimethalin was mixed quizalofop, control of barnyardgrass was 94 to 98% at 14, 28, and 42 DAT with all herbicide mixtures. A neutral interaction occurred for CL-111, CLXL-745, and red rice control when treated with all herbicide mixtures and evaluation dates. Rice yield decreased when not treated with the initial quizalofop application.
Osterholt, Matthew, "Interactions Observed with Clomazone plus Pendimethalin when Mixed with Postemergence Rice Herbicides" (2018). LSU Master's Theses. 4830.