Indaziflam is a PRE herbicide for control of annual grass and broadleaf weeds in numerous settings, including managed roadsides, railroads, and noncroplands. There is a need for new and improved PRE herbicides for herbaceous vegetation management along roadsides; however, off-target crop injury via spray drift is a concern because of the close proximity of roadside applications to the wide array of crops grown throughout the southeastern United States where indaziflam is used. Greenhouse research was conducted to evaluate the effect of PRE and POST simulated indaziflam spray drift rates on the growth of cotton, bell pepper, soybean, squash, tobacco, and tomato. Simulated indaziflam spray drift rates were 100, 20, 10, 5, or 2.5% of a 73 g ai ha⁻¹ application rate, whereas other herbicide treatments included for comparative purposes were applied at 10% of a typical North Carolina roadside vegetation management application rate. These included sulfometuron (4 g ai ha⁻¹), aminocyclopyrachlor metsulfuron (11 3.5 g ai ha⁻¹), clopyralid triclopyr (21 63 g ai ha⁻¹), or aminopyralid (12 g ai ha⁻¹). In general, plant growth responses varied among herbicides and application timings. Across all evaluated parameters, indaziflam at the 10% simulated drift rate adversely effected plant growth similarly or less than all other herbicides when applied PRE (squash and tomato), POST (bell pepper and soybean), and PRE or POST (cotton and tobacco). No clear trends were observed regarding indaziflam application timing, as PRE squash and tomato, and POST bell pepper and soybean applications were safer than their respective alternative timing, and no significant differences were detected between timings on cotton or tobacco. Across application timings, plant susceptibility to indaziflam-simulated spray drift rates ranked cotton < tobacco < tomato < squash < pepper < soybean. Finally, it should be noted that the lowest simulated indaziflam drift rate (2.5%) caused greater than 20% root mass reduction on cotton (POST), bell pepper (PRE and POST), soybean (PRE and POST), squash (PRE), and tomato (POST). Although this research supports indaziflam use along roadsides, it still poses an off-target plant injury risk. Future research should evaluate techniques to minimize spray drift from roadside pesticide applications.

Nomenclature: Aminocyclopyrachlor; aminopyralid; clopyralid; indaziflam; metsulfuron; sulfometuron; bell pepper, Capsicum annuum L. ‘California Wonder’; cotton, Gossypium hirsutum L. ‘DP 1252 B2RF’; soybean, Glycine max (L.) Merr. ‘SS 5911N R2’; squash, Cucurbita pepo L. ‘Early Prolific Straightneck’; tobacco, Nicotiana tabacum L. ‘K-326’; tomato, Solanum lycopersicum L. ‘Homestead 24’.

Indaziflam es un herbicida PRE para el control de Poa annua y malezas de hoja ancha en numerosas situaciones, incluyendo bordes de caminos, vías de ferrocarriles y áreas no agrícolas. Existe una necesidad de tener herbicidas PRE nuevos y mejorados para el manejo de vegetación herbácea en bordes de caminos. Sin embargo, el daño a cultivos aledaños vía deriva de aspersión causa preocupación debido a la proximidad de las aplicaciones en los bordes de caminos a una gran variedad de cultivos producidos a lo largo del sureste de los Estados Unidos donde se usa indaziflam. Se realizó una investigación en invernaderos para evaluar el efecto de deriva simulada con dosis de indaziflam en PRE y POST sobre algodón, pimentón, soya, calabacín, tabaco, y tomate. Las dosis de deriva simulada de indaziflam fueron 100, 20, 10, 5, ó 2.5% de un