Greenhouse experiments were conducted to determine the effects of herbicide placement on POST smooth crabgrass and annual bluegrass control. Soil-plus-foliar, soil-only, and foliar-only applications of indaziflam (52.5 g ai ha−1), dithiopyr (560 ai g ha−1), or quinclorac (840 g ai ha−1) were made to one-tiller smooth crabgrass plants. Similarly, indaziflam (52.5 g ha−1), foramsulfuron (29 g ai ha−1), or prodiamine (840 g ai ha−1) were applied to nontillering annual bluegrass plants in an identical manner. No differences in smooth crabgrass control were detected between soil-plus-foliar and soil-only applied indaziflam from 21 to 35 d after treatment (DAT). By 28 DAT, smooth crabgrass control and biomass reductions with these indaziflam treatments were ≥ 90% and not different than quinclorac. Comparatively, smooth crabgrass control with foliar-only applications of indaziflam never exceeded 28%. Responses on annual bluegrass were similar as soil-plus-foliar and soil-only applied indaziflam exhibited greater efficacy than indaziflam applied foliar-only. By 28 DAT, annual bluegrass control and aboveground biomass reductions with soil-plus-foliar and soil-only treatments were ≥ 86% and not different from foramsulfuron. Comparatively, foliar-only applications of indaziflam controlled annual bluegrass ≤ 2%. These results indicate that root absorption is required for POST control of smooth crabgrass and annual bluegrass with indaziflam. Further research is needed to determine if techniques to enhance indaziflam contact with soil will enhance POST smooth crabgrass and annual bluegrass control in the field.
Nomencalture: Dithiopyr; indaziflam; foramsulfuron; prodiamine; quinclorac; annual bluegrass, Poa annua L.; smooth crabgrass, Digitaria ischaemum (Schreb.) Schreb. ex Muhl.
Se realizaron experimentos de invernadero para determinar los efectos de la localización de herbicidas en el control POST de Digitaria ischaemum y Poa annua. Aplicaciones al suelo-más-foliar, solamente-suelo y solamente-foliar de indaziflam (52 g ai ha−1), dithiopyr (560 g ai ha−1) o quinclorac (840 g ai ha−1) fueron realizadas en plantas de D. ischaemum en estado de un hijuelo. Similarmente, indaziflam (52 g ai ha−1), foramsulfuron (29 g ai ha−1) o prodiamine (840 g ai ha−1) fueron aplicadas a plantas de P. annua sin hijuelos en forma idéntica. No se detectaron diferencias en el control de D. ischaemum entre suelo-más-foliar y solamente-suelo con indaziflam entre 21 y 35 d después del tratamiento (DAT). A 28 DAT, el control y la reducción de biomasa con estos tratamientos con indaziflam fueron ≥90% y no fueron diferentes del quinclorac. Comparativamente, el control de D. ischaemum con aplicaciones solamente-foliar de indaziflam nunca excedió 28%. Las respuestas de P. annua fueron similares, en tanto que las aplicaciones suelo-más-foliar y solamente-suelo de indaziflam exhibieron mayor eficacia que indaziflam aplicado solamente-foliar. A 28 DAT, el control y la reducción de biomasa aérea de P. annua con tratamientos suelo-más-foliar y solamente-suelo fueron ≥86% y no fueron diferentes al foramsulfuron. Comparativamente, aplicaciones solamente-foliar de indaziflam controlaron P. annua ≤2%. Estos resultados indican que se requiere absorción radicular para el control POST de D. ischa
