Applied Turfgrass Science最新文献

Etiolation is an abnormal elongation and chlorosis of turfgrass plants that has become problematic in recent years, and bacteria have been implicated as causal agents. The frequent reports of etiolation are of concern to turfgrass managers, since management practices for bacterial diseases in turf are not well developed. The purpose of this research trial was to evaluate fungicides and nonregistered antibiotics for management of etiolation in creeping bentgrass turf. This 2-year field study evaluated oxytetracycline, streptomycin sulfate, acibenzolar-S-methyl + chlorothalonil (ASM + C), potassium phosphite (PPP), hydrogen dioxide, fosetyl-Al [pigmented (FAP) and nonpigmented (FA)], and copper + mancozeb for their effects on etiolation caused by Xanthomonas translucens on creeping bentgrass putting-green turf. Reductions in etiolation severity were observed with oxytetracycline treatment in both years and with ASM + C in the second year of study. While ASM + C did not reduce etiolation in the first year, turf quality with ASM + C alone and in combination with PPP was superior to all other treatments in both years. While PPP and FAP did not reduce etiolation, turf quality of these plots was often better than the control. Both antibiotics in addition to copper + mancozeb had phytotoxicity that reduced turf quality. Preventative applications of ASM + C were the most effective in reducing etiolation of creeping bentgrass while maintaining turf quality.

Paint applied as an aerosol has been the standard in marking water hazards and out-of-bounds lines on golf courses. Experiments were conducted in Citra, FL and Manhattan, KS to compare aerosol treatments to paint applied in bulk with a backpack applicator or sport field line applicator, with or without the inclusion of the growth regulator Primo (active ingredient trinexapac ethyl), for persistence of water hazard and out-of-bounds lines on bermudagrass. Regardless of applicator type, no water hazard or out-of-bounds line retained acceptable color intensity longer than 5 weeks. Applying red paint in bulk with Primo through the backpack sprayer or sport field line applicator resulted in lines that provided a lateral water hazard line of acceptable color intensity for about 16 and 8 days longer in Florida and Kansas, respectively, compared to aerosol-applied paint. Likewise, white paint applied with Primo to mark out-of-bounds lines with a backpack applicator persisted about 6 days longer in Florida than that applied with an aerosol. Enhancing line intensity and persistence with bulk paint that is lower in price compared to aerosol paint, combined with Primo, may be of interest to golf course superintendents and others responsible for marking water hazard and out-of-bounds lines on golf courses.

Soil cultivation is commonly used to manage organic matter (OM) accumulation in golf course putting greens. Our objectives were to determine: (i) if hollow-tine cultivation is more effective than solid-tine cultivation at managing OM and water infiltration, (ii) if venting methods are effective at managing OM and water infiltration, and (iii) if venting alters or interacts with effects of early- or late-season cultivation. The study was a 3 × 5 factorial repeated on two ‘Providence’ creeping bentgrass (Agrostis stolonifera L.) research putting greens. Tine treatments were hollow-tine, solid-tine, or no-tine cultivation. Venting treatments were Hydroject, PlanetAir, quad needle tine, bayonet tine, or no venting. Soil samples were collected and analyzed for OM content using loss on ignition. Water infiltration rates were determined in situ. After 2 years, there were few consistent differences found among the tine and venting treatments, and there were no significant interactions regarding OM concentration. This response was attributed to the small amount of surface area impacted by cultivation and to the equalization of topdressing quantity across all treatment combinations. Hollow-tine and solid-tine cultivation increased infiltration compared with no cultivation. In general, Hydroject treatments increased water infiltration rates more than all other venting treatments regardless of tine treatment.

Amicarbazone controls annual bluegrass (Poa annua L.) in bermudagrass [Cynodon dactylon (L.) Pers.] turf overseeded with perennial ryegrass (Lolium perenne L.). There is, however, a risk of perennial ryegrass injury, depending on application timing. The objective of this research was to determine the effect of the timings between overseeding and amicarbazone applications on perennial ryegrass. Amicarbazone was applied at 0, 2.1, and 2.8 oz a.i./acre at 6, 8, 10, and 12 weeks after overseeding (WAOS) in Florida and South Carolina. In Florida, perennial ryegrass maximum injury was greater at 6 WAOS (79%) than at 8 to 12 WAOS (6 to 30%). Conversely, in South Carolina, minor perennial ryegrass injury was observed in plots treated 6 to 10 WAOS, but 48% injury was observed in plots treated 12 WAOS. In all sites, plots treated at 6 WAOS exhibited up to fourfold reduction in perennial ryegrass cover compared with the untreated control (88%). Overall, annual bluegrass control was acceptable to excellent (73–99%) with amicarbazone applications in South Carolina. In Florida 24 weeks after initial treatment, all treatments controlled annual bluegrass 64 to 98% except applications at 6 WAOS (25–42%). Results suggest that amicarbazone should be applied at least 8 to 10 WAOS to minimize loss of perennial ryegrass cover, but applications at this time will provide adequate annual bluegrass control.

Larvae of the Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae), are rarely found in golf course putting greens despite seemingly ideal characteristics. Sand-based putting green root zones are often maintained at relatively low volumetric water contents that could be unsuitable for survival of P. japonica eggs or larvae. Putting greens also receive frequent applications of fungicides throughout the growing season, and it is possible that these chemicals deter females from laying eggs. This study was conducted to determine how the volumetric water content of sand putting green soils and the application of the fungicide active ingredients propiconazole and chlorothalonil affect the oviposition (i.e., egg laying) behavior of the Japanese beetle. In a soil moisture choice assay, adult females avoided investigating (i.e., digging) in soils maintained just above the wilting point of the turfgrass (∼5% volumetric water content). In another experiment, neither the application of propiconazole nor chlorothalonil had any effect on female investigation. Recovery of larvae was low in both assays, possibly due to the coarse texture of the sandy soils used in these studies. These findings suggest that conservative irrigation could lessen infestations of P. japonica, and that single applications of propiconazole or chlorothalonil do not affect female oviposition choice.