Buckhorn plantain is a perennial weed in turfgrass and efficacy of POST herbicides is often inconsistent for control in spring. Indaziflam is a cellulose biosynthesis inhibitor used for PRE control of annual weeds in turf and applications have shown to be injurious to established buckhorn plantain. The objectives of this research were to evaluate (1) effects of indaziflam application rate and placement on buckhorn plantain injury; (2) effects of tank-mixing indaziflam with POST herbicides for buckhorn plantain control; and (3) physiological effects of indaziflam on absorption and translocation of ¹⁴C-2,4-D in buckhorn plantain. In greenhouse experiments, indaziflam reduced buckhorn plantain shoot mass 61 to 75% from the nontreated at 4 wk after treatment (WAT) and hierarchical rank of application placements were: foliar soil ≥ soil ≥ foliar. Differences in biomass reduction from application rates (27.5 and 55 g ai ha⁻¹) were not detected. In field experiments, indaziflam at 55 g ha⁻¹ controlled buckhorn plantain 34% at 9 WAT but enhanced the speed of control from all herbicides tested in tank mixtures. Exclusive applications of 2,4-D or 2,4-D dicamba MCPP provided poor control (< 70%) of buckhorn plantain at 9 WAT, but tank mixtures with indaziflam provided 81 and 98% control, respectively. Fluroxypyr and simazine alone controlled buckhorn plantain < 38% but tank mixtures with indaziflam enhanced control more than twice as much from exclusive applications. Tank-mixing indaziflam with metsulfuron did not improve control from metsulfuron alone after 9 wk. Bermudagrass injury was not detected from any treatment. In laboratory experiments, ¹⁴C-2,4-D absorption and translocation in buckhorn plantain was similar with or without indaziflam tank mixtures at 72 and 168 h after treatment. Overall, indaziflam may improve buckhorn plantain control from POST herbicides by providing additive phytotoxicity in tank mixtures in spring.

Nomenclature: Buckhorn plantain, Plantago lanceolata L.; bermudagrass, Cynodon dactylon L.

Plantago lanceolata es una maleza perenne en céspedes y la eficacia de herbicidas POST es comúnmente inconsistente para su control en la primavera. Indaziflam es un inhibidor de la biosíntesis de cellulose usado para el control PRE de malezas anuales en césped y su aplicación ha demostrado ser dañina para plantas establecidas de P. lanceolata. Los objetivos de esta investigación fueron evaluar (1) los efectos de la dosis y lugar de aplicación de indaziflam sobre el daño de P. lanceolata; (2) los efectos de mezclar en tanque indaziflam con herbicidas POST para el control de P. lanceolata; y (3) los efectos fisiológicos de indaziflam en la absorción y translocación de ¹⁴C-2,4-D en P. lanceolata. En experimentos de invernadero, indaziflam redujo la masa de tejido aéreo de P. lanceolata 61 a 75% en comparación al testigo no-tratado a 4 semanas después del tratamiento (WAT) y el ranking jerárquico del lugar de aplicación fue: foliar suelo ≥ suelo ≥ foliar. No se detectaron diferencias en la reducción de biomasa según la dosis de aplicación (27.5 y 44 g ai ha⁻¹). En los experimentos de campo, indaziflam a 55 g ha⁻¹ controló P. lanceolata 34% a 9 WAT, pero mejoró la velocidad de control de todos los herbicidas evaluados en mezclas en tanque. Aplicaciones exclusivas de 2,4-D o 2,4-D dicamba MCPP brindaron un control pobre (<70%) de P. lanceolata