Semester of Graduation
Spring 2026
Degree
Master of Science (MS)
Department
Plant, Environmental, and Soil Sciences
Document Type
Thesis
Abstract
Iptriazopyrid is a novel HPPD inhibiting herbicide currently being registered for use in rice production. Studies were conducted in 2024 and 2025 at the H. Rouse Caffey Rice Research Station (RRS) near Crowley, Louisiana to evaluate herbicide mixture interactions when iptriazopyrid was applied independently or mixed. Across all of the studies evaluated, iptriazopyrid was applied at 50 g ai ha-1 alone and mixed with auxin, contact, ACCase inhibiting, and ALS inhibiting herbicides.
Auxin herbicides consisted of florpyrauxifen at 29 g ai ha-1, triclopyr at 420 g ae ha-1, quinclorac at 420 g ae ha-1, or 2,4-D at 1060 g ae ha-1. Iptriazopyrid alone controlled barnyardgrass 68 to 80% across rating dates whereas broadleaf signalgrass was only controlled 27 to 31%. Antagonism for barnyardgrass control was observed across all rating dates when iptriazopyrid was mixed with triclopyr or 2,4-D. Iptriazopyrid mixed with 2,4-D was also antagonistic for broadleaf signalgrass control. The most compatible mixture was iptriazopyrid mixed with florpyrauxifen.
Contact herbicides consisted of carfentrazone at 17.5 g ai ha-1, saflufenacil at 25 g ai ha-1, bentazon at 840 g ai ha-1, propanil at 4500 g ai ha-1, or thiobencarb at 6700 g ai ha-1. When iptriazopyrid was mixed with bentazon, propanil, and thiobencarb antagonism was observed for barnyardgrass control at 14, 21, and 35 DAT. Antagonism was also documented for yellow nutsedge and rice flatsedge when iptriazopyrid was mixed with carfentrazone, saflufenacil, and thiobencarb at 35 DAT.
ACCase inhibiting herbicides consisted of quizalofop at 120 g ai ha-1, fenoxaprop at 122 g ai ha-1, cyhalofop at 417 g ai ha-1, or quizalofop + safener at 120 g ai ha-1. Barnyardgrass control was not antagonized when iptriazopyrid was mixed with ACCase inhibiting herbicides at 28 and 35 DAT. However, iptriazopyrid added sedge and broadleaf activity to the mixtures.
ALS inhibiting herbicides consisted of bispyribac-sodium at 40 g ai ha-1, penoxsulam at 32 g ai ha-1, halosulfuron at 70 g ai ha-1, halosulfuron plus thifensulfuron at 53 g ai ha-1, halosulfuron plus prosulfuron at 105 g ai ha-1, bensulfuron at 70 g ai ha-1, or orthosulfamuron at 147 g ai ha-1. Antagonism was observed consistently for barnyardgrass control when iptriazopyrid was mixed with bispyribac-sodium, penoxsulam and orthosulfamuron across both years. Halosulfuron containing products were not consistently antagonistic when mixed with iptriazopyrid and could possibly be a compatible mixture for sedge and broadleaf control.
Date
3-26-2026
Recommended Citation
Sparks, Gavin R., "Mixture Interactions of Iptriazopyrid in Louisiana Rice" (2026). LSU Master's Theses. 6332.
https://repository.lsu.edu/gradschool_theses/6332
Committee Chair
Webster, Connor L.
LSU Acknowledgement
1
LSU Accessibility Acknowledgment
1