Applied Turfgrass Science最新文献

Laboratory and field studies were conducted in 2010 and 2011 to evaluate the volatility of commonly used turfgrass broadleaf herbicides when applied to tall fescue (Lolium arundinaceum Schreb.). Herbicides were applied at the highest label rate for dandelion (Taraxacum officinale G.H. Weber ex Wiggers) control. Turfgrass flats treated with herbicides were placed in enclosures containing tomato plants. In laboratory experiments, tomatoes exposed to turfgrass treated with products containing amine formulations of synthetic auxin herbicides exhibited minimal injury, but exposure to products containing low-volatile ester formulations caused significant negative effects on tomato quality, epinasty, and callus formation. Generally, products containing low-volatile ester formulations of synthetic auxin herbicides exhibited less volatility, compared to 2,4-D butyl ester (volatile standard). A subsequent field study corroborated the laboratory results, although injury symptoms were less severe. Turfgrass managers should avoid herbicides containing low-volatile ester formulations when vulnerable non-target plants are nearby, and/or when environmental conditions such as high temperature favor volatility.

As an athlete accelerates, stops, and changes direction, numerous forces are transmitted to the lower extremities. The interaction between an athlete's shoe and the playing surface has been indicated as a factor in lower extremity injury risk. In particular, high rotational forces may result in increased injuries to the lower extremities. Rotational traction forces produced by eight different cleated shoes on Kentucky bluegrass (Poa pratensis L.), AstroTurf GameDay Grass 3D, FieldTurf Revolution, and Sportexe Omnigrass 51 under three normal loads (vertical forces) of 787, 1054, and 1321 N were measured using Pennfoot, a portable traction testing device. Of the treatments in this study, shoe type influenced rotational traction most, with differences among shoes being nearly four times as large as those among playing surfaces. Traction was either the same or within several Nm on each surface tested. Traction on the three synthetic turf surfaces ranged from 49.3 to 53.1 Nm and the traction level of Kentucky bluegrass was 52.3 Nm. Traction levels among shoes ranged from 43.8 to 58.6 Nm. The results of this study indicate that footwear selection has a larger effect on rotational traction, and potentially injury risk, than the playing surfaces evaluated in this study.

Flumioxazin is a protoporphyrinogen oxidase (Protox) inhibitor with potential for postemergence (POST) control of annual bluegrass (Poa annua L.) and preemergence (PRE) control of smooth crabgrass [Digitaria ischaeum (Schreb.) Schreb. ex Muhl.] in bermudagrass [Cynodon dactylon (L.) Pers.]. However, flumioxazin efficacy is reduced under low temperatures, and control is often inconsistent on mature annual bluegrass. The objective of this research was to evaluate the use of adjuvants on flumioxazin efficacy for POST control of annual bluegrass and residual smooth crabgrass in bermudagrass. Tank-mixing methylated seed oil, nonionic surfactant, or ammonium sulfate did not improve POST annual bluegrass control from flumioxazin at 0.42 kg active ingredient (a.i.) ha⁻¹ alone. Granular urea antagonized flumioxazin efficacy and increased the time to achieve 50% annual bluegrass control (C₅₀) by more than 4 weeks. Flumioxazin alone controlled annual bluegrass >80% at 9 weeks after treatment in both years. All treatments provided excellent (90 to 100%) control of smooth crabgrass at 4 months after treatment (MAT) and ≥89% control at 5 MAT. All flumioxazin treatments provided >70% control of smooth crabgrass and reduced grid count cover >65% from the untreated at 7 MAT. Although adjuvants did not enhance speed of annual bluegrass control from late-winter applications, flumioxazin alone controlled annual bluegrass >80%, and provided >80% PRE control of smooth crabgrass.

This study compared simulated spills of three fuel types at two temperatures on turf damage and recovery. Field research was initiated in Fayetteville, AR on 8 June 2012. Experimental design was a randomized complete block design with four replications. Factors included fuel type, application temperature, and turfgrass surface. Fuel types were petroleum diesel (PD), a 20% biodiesel and 80% petroleum diesel blend (B20), and 100% biodiesel (B100) applied at 32°C and at 74°C. Turfgrass surfaces included creeping bentgrass (Agrostis stolonifera L. ‘SR1020’) and bermudagrass (Cynodon dactylon var. dactylon ‘Tifeagle’) putting greens and creeping bentgrass (‘SR1020’), bermudagrass (‘Tifsport’), and zoysiagrass (Zoysia japonica Steud. ‘Meyer’) fairways. For Trial 1, 20 mL was applied at the center of each 929-cm² plot on 8 June 2012, and data collection extended through 20 July 2012 (42 days). For Trial 2, 10 mL was applied at the center of each 929-cm² plot on 20 July 2012, and data collection extended through 31 Aug. 2012 (42 days). In 8 of 10 comparisons, there was a statistically significant fuel type-by-week-after-application interaction, with PD applications resulting in greater damage and slower recovery and B100 resulting in less damage and more rapid recovery. B20 was generally intermediate to PD and B100.

Many turfgrass extension bulletins and herbicide labels recommend prolonging or suspending mowing practices 1 day or more before and/or after herbicide applications to increase efficacy. However, the effect of mowing timing on herbicide efficacy has not been sufficiently explored. Field experiments were conducted to evaluate the influence of herbicide selection and mowing timing relative to herbicide application on the control of ground ivy (Glechoma hederacea L.). The three mowing treatments included mowing 30 min before herbicide application, mowing 30 min after herbicide application, and not mowing for at least 7 days prior to and at least 3 days after herbicide application. Aminocyclopyrachlor resulted in the greatest reduction of ground ivy cover in 2011 and 2012. Like aminocyclopyrachlor, 2,4-D ester and metsulfuron reduced ground ivy cover both years, while triclopyr reduced ground ivy cover as well as aminocyclopyrachlor in 2012. Although 2,4-D + mecoprop (MCPP) + dicamba was not among the best performing herbicides, it reduced ground ivy cover compared with the untreated check in both years. There were no mowing or mowing-by-herbicide interactions on any of the rating dates. Thus, this research suggests that the timing of lawn mowing relative to herbicide application has little measurable impact on herbicide efficacy on ground ivy.

Flazasulfuron may be safely applied to actively growing seashore paspalum (Paspalum vaginatum Sw.), but applications for annual bluegrass control in late winter or spring could be injurious. A 3-year field experiment was conducted to evaluate tank mixtures of flazasulfuron with amicarbazone at turf dormancy or partial greenup to determine if combinations could enhance annual bluegrass control and mitigate seashore paspalum injury compared to exclusive treatments. Single applications of flazasulfuron at 26 g a.i. ha⁻¹ at both timings provided good (80 to 89%) to excellent (>90%) control of annual bluegrass in 2 of 3 years, while sequential applications provided ≥86% control at both timings in all 3 years. Tank mixtures of flazasulfuron at 26 g ha⁻¹ plus amicarbazone at 196 g ha⁻¹ significantly improved annual bluegrass control from flazasulfuron alone at 26 g ha⁻¹ at both timings in 2 of 3 years. Amicarbazone tank mixtures did not improve annual bluegrass control from flazasulfuron at 52 g ha⁻¹ alone at either timing. Late winter applications of amicarbazone at 196 g ha⁻¹ alone provided poor annual bluegrass control (<70%) in 2 of 3 years while applications at turf greenup provided ≥88% control in all 3 years. Pronamide provided fair control (70 to 78%) and excellent control (≥90%) of annual bluegrass in 2 of 3 years when applied at dormancy or at greenup, respectively. All flazasulfuron treatments caused 36 to 54% injury when applied at greenup but single applications at dormancy caused 13 to 29% injury. Amicarbazone and pronamide alone never injured seashore paspalum greater than 17% at both application timings and treatments at greenup provided the best combinations of annual bluegrass control and turf tolerance.

Weed control is important during establishment of cool-season grasses, especially when seeded in spring near summer annual weed germination. Our objectives were to determine (i) turf safety and weed control from sequential applications of newly-released herbicides on tall fescue at three seeding dates (May, June, July) and (ii) turf safety and weed control from newly-released herbicides applied at seeding or shortly after emergence of spring-seeded Kentucky bluegrass or tall fescue. No herbicides tested negatively affected turfgrass establishment and usually improved turf establishment by reducing weed competition. Mesotrione consistently provided effective weed control and turf cover from either single or sequential applications over different locations, years, seeding dates, and turf species. Quinclorac or siduron applied as single or sequential applications or quinclorac+carfentrazone as a single application provided effective weed control and turf cover depending on seeding date and application regime. Although spring seeding can be achieved with high maintenance, it is strongly recommended to seed cool season grasses at the optimal time from late summer to early fall.