Interaction between saflufenacil and imazethapyr in red rice (Oryza ssp.) and hemp sesbania (Sesbania exaltata) as affected by light intensity

Abstract

Saflufenacil is a broadleaf herbicide for preplant burndown and pre-emergence applications in various crops. This study was established to evaluate the absorption and translocation of saflufenacil in hemp sesbania and imazethapyr in red rice as a function of their post-emergence interaction and light intensity. Imazethapyr plus saflufenacil provided a greater uptake (30%) and translocation (35%) of (14) C-imazethapyr than imazethapyr alone. In the section above treated leaf (ATL), a higher percentage of the absorbed imazethapyr (23%) was quantified in the imazethapyr plus saflufenacil treatment after 168 h. Faster basipetal movement of imazethapyr was identified under higher light availability. Absorption of (14) C-saflufenacil ranged from approximately 40 to 60% among herbicide and light intensity treatments. At 12 and 24 h after treatment (HAT) a greater percentage (15-20%) of the absorbed saflufenacil was quantified above the treated leaf at the two lower light intensities. Similar trends were observed for basipetal movement of saflufenacil. Saflufenacil enhanced absorption, overall translocation and acropetal movement of imazethapyr in the TX4 red rice. Basipetal movement of imazethapyr was faster under higher light intensities. Overall, imazethapyr improved absorption of saflufenacil in hemp sesbania plants. Reduction in light intensity resulted in greater translocation of saflufenacil, promoting acropetal and basipetal distribution at the two lower light intensity treatments.