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Research was conducted to determine the tolerance of 11 grass species used in minimal‐to‐no‐mow turf areas to three postemergence herbicides applied at one‐ and twofold the maximum label rates in 2018 and 2019. Grasses were transplanted into field plots in West Lafayette, IN, in 2018 and 2019, allowed time to establish (∼1−2 mo), and then either treated with one application of quinclorac, sethoxydim, and topramezone at two rates or not treated. All 11 grass species had acceptable tolerance (≤20% injury) to quinclorac applied at 0.845 kg acid equivalent (a.e.) ha–1. Quinclorac at 1.69 kg a.e. ha–1 produced moderate injury (≥21% injury) on only little bluestem [Schizachyrium scoparium (Michx.) Nash.], prairie dropseed [Sporobolus heterolepis (A. Gray) A. Gray], and switchgrass (Panicum virgatum L.). Strong creeping red fescue (Festuca rubra L. ssp. rubra Gaudin), which had ≤5% injury from all three herbicides, exhibited the greatest tolerance among grass species tested. With the exception of strong creeping red fescue, sethoxydim significantly injured all other grass species. Injury from topramezone varied among grass species and herbicide rates. Grasses tolerant (≤20% injury) to topramezone at both rates were big bluestem (Andropogon gerardii Vitman), broomsedge bluestem (Andropogon virginicus L.), indiangrass [Sorghastrum nutants (L.) Nash], strong creeping red fescue, and tall fescue [Festuca arundinacea Schreb.; syn. Schedonorus arundinaceus (Schreb.) Dumort., nom. cons.]. Tolerance among species was variable to quinclorac, sethoxydim, and topramezone, and thus turf managers should first identify desired grass species prior to herbicide application. Core Ideas: Information is needed on the herbicide tolerance of grass species used on golf courses.Eleven grasses species were tolerant to quinclorac applied at a rate 0.845 kg acid equivalent ha−1.Sethoxydim significantly injured 10 of 11 grass species.Injury from topramezone varied among grass species and herbicide rates.Turf managers must identify desired grasses prior to herbicide selection and application. [ABSTRACT FROM AUTHOR]

Renovation is an opportune time for golf courses to address annual bluegrass (Poa annua L.) weed populations. Dazomet (tetrahydro-3,5-dimethyl-2H-1,3,5- thiadiazine-2-thione) is an effective fumigant, but without a tarp cover, it is only effective at the highest labeled rates. Fraise mowing cultivation could be used to help remove surface material and allow practitioners to effectively fumigate at lower rates. In Summer 2018 and Summer 2019, two cool-season fairway renovation experiments were conducted in East Lansing, MI. The objective of these experiments was to assess annual bluegrass control and creeping bentgrass establishment following dazomet applications to fraise mowed surfaces. In the first experiment (fraise mowing surface disturbance experiment), dazomet was applied at a fixed rate (294 kg·ha-1) to fraise mowed plots at varying levels of surface disturbance (0%, 15%, 50%, and 100%) to a depth of 1.9 cm. In the second experiment (dazomet rate experiment), fraise mowing removed 100% of surface material at a depth of 1.9 cm and dazomet was applied at five rates (0, 294, 588, 147 + 147, and 294 + 294 kg·ha-1). Both experiments were conducted on two soils (sand topdressed vs. native) and evaluated two methods of fumigant incorporation (solid-tine cultivation vs. tillage). Five days after treatments were applied, plots were seeded with 'Pure Select' creeping bentgrass (Agrostis stolonifera L.). The level of fraise mowing surface disturbance had no effect on annual bluegrass emergence, and creeping bentgrass cover was poorest in native soils at the highest levels of surface disturbance. In the dazomet rate experiment, dazomet applied twice at 294 kg·ha-1 provided the most consistent control of annual bluegrass. With the exception to single applications of 294 in 2018, all dazomet treatments allowed for greater creeping bentgrass establishment than the nontreated control. Fraise mowing cultivation may simplify the removal of surface material from large areas; however, even when combined with dazomet applied at the highest rates, it fails to provide complete annual bluegrass control. [ABSTRACT FROM AUTHOR]

Two desirable traits consistent in emerging creeping bentgrass (Agrostis stolonifera L.) cultivars are increased canopy density and fine leaf texture. Although the former is often associated with reduced incorporation of applied materials into the turf system, the effects of the latter have not yet been characterized. Some practitioners believe these boundaries can be overcome by topdressing with a dried sand, which they propose settles differently than conventional moist sand. In 2018, two topdressing studies were conducted to evaluate incorporation of moist and dried topdressing sands when applied to six creeping bentgrass cultivars of varying textures into vertically mowed and uncultivated systems. Cultivars were topdressed with dried sand or with moist sand and then incorporated with one of two brushing systems. Across trials, neither brush consistently outperformed the other. A larger proportion of applied topdressing sand was retained by the vertically mowed system and was unaffected by the moisture content of sand. Less sand was retained by uncultivated systems, and the distribution of both sands changed significantly. For moist sands, finer-textured cultivars, in general, corresponded with greater removal of coarse fractions and a greater retention of fine fractions. Therefore, we provide supporting evidence that topdressing into vertically mowed systems, regardless of sand moisture content, results in enhanced sand incorporation. When topdressing uncultivated, fine-textured bentgrass putting green systems, however, practitioners could benefit from topdressing with dried sands. [ABSTRACT FROM AUTHOR]

Core Ideas: Trinexapac‐ethyl (TE) is a common plant growth regulator used in turfgrass systems.The effects of TE on herbicide efficacy to control smooth crabgrass were unknown.Mixing TE with postemergence herbicides did not affect smooth crabgrass control. [ABSTRACT FROM AUTHOR]