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Grant J. Klein and Robert L. Green

Turfgrass management best management practices (BMPs) encompass a wide variety of activities, including fertilization, irrigation, mowing, pest control, and soil management. Little attention is given to determining just how effective information regarding BMPs is being assimilated and used by professional turfgrass managers. The objectives of this study were to assess the current perception and implementation of selected turfgrass BMPs and to determine whether or not those perceptions and implementations differed 1) between turfgrass advisors and managers and 2) between general and sports turfgrass managers. Professionals from the turfgrass industry, with an average of 13 years of experience and largely comprised of decision-makers (88%), were surveyed at the University of California, Riverside, Turfgrass Research Conference and Field Day in Fall 1998 and 1999. Turfgrass managers, especially sports turfgrass managers, were found to be the most committed to implementing the BMPs in the survey. Overall, survey respondents considered BMPs to be important and not highly difficult to implement. Limitations to the adoption of BMPs were a lack of financial backing, employee education, and necessary time—all of which could be remedied with a sufficient commitment of resources by the turfgrass industry.

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Pamela Korczynski, James E. Faust and Robert Klein

Paclobutrazol drenches (1 ppm, 118.4 mL per pot) were applied to Poinsettia `Freedom' Red' on 1, 11, 21, and 31 Oct. in 1997 and 1998. Plant heights were recorded twice weekly throughout the experiment, and internode length and bract area were measured at harvest. The total bract area of the three true bracts and the top three transitional bracts was reduced by 5.8%, 13.6%, 4.2%, and 2.3% for the 1, 11, 21, and 31 Oct. application dates, respectively; however, all plants were highly marketable. At the time of each drench application, the most newly unfolded leaf was marked. The internode lengths for the three internodes below this leaf and the internodes that developed after the drench application were typically between 5 and 10 mm in length, while the internode lengths of the control plants were typically 10 to 25 mm, depending on node number. Plant height increased 62, 51, 47 and 19 mm following application on the 1, 11, 21, and 31 Oct. application dates, respectively. The 1, 11, 21, and 31 Oct. drench applications reduced total stem elongation from 1 Oct. to anthesis by 64%, 49%, 28%, and 15%, respectively. Paclobutrazol drenches did not affect time to anthesis.

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James E. Faust, Pamela C. Korczynski and Robert Klein

Experiments were conducted to evaluate the effects of paclobutrazol drenches on poinsettia (Euphorbia pulcherrima) `Freedom Red' height and flowering. In 1997 and 1998, paclobutrazol drenches [(a.i.) 0.118 mg/container; (28,350 mg = 1.0 oz)] were applied to poinsettias grown under natural photoperiods on four dates from 1 Oct. to 2 Nov. On plants receiving the paclobutrazol drench application during the second week in October, bract area was reduced by 15% and 12% compared with that of the control in 1997 and 1998, respectively; however, the bract area reduction was commercially acceptable. Anthesis date was not significantly affected during either year. Plant height and internode length measurements indicate that paclobutrazol drench applications had both a rapid and a long-term impact on poinsettia stem elongation. Paclobutrazol drenches applied in late October or early November are an effective tool for controlling late-season stem elongation of `Freedom Red' poinsettias grown under natural photoperiods. These late-season applications have the least risk for negatively affecting bract size while still reducing stem elongation in the last few weeks of the crop. Chemical names used: (±)-(R*,R*)-b-[(chlorophenyl)methyl]-a-(1,1-dimethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol).

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Robert L. Green, Grant J. Klein, Francisco Merino and Victor Gibeault

Bermudagrass [Cynodon dactylon (L.) Pers × C. transvaalensis Burtt-Davy] greens across the southern United States are normally overseeded in the fall to provide a uniform green playing surface and tolerance to wear during winter bermudagrass dormancy. The spring transition from overseed grass back to bermudagrass is a major problem associated with overseeding because there can be a decline in putting green quality and playability. There have been recommendations, but relatively few published reports, on the effect of treatments associated with seedbed preparation and overseeding on bermudagrass spring transition. The objective of this 2-year study was to determine if spring transition of an overseeded `Tifgreen' bermudagrass green was influenced by fall-applied scalping level, chemical, and seed rate treatments. Treatment factors and levels were designed to reflect the range of practices used by golf course superintendents in the region at the time of the study. The green was located in the Palm Springs, Calif., area, which has relatively mild winters and a low desert, southern California climate. The first year of the study was from Sept. 1996 to July 1997 and the second year was from Sept. 1997 to July 1998. Scalping level treatments included a moderate and severe verticut and scalp; chemical treatments included a check, trinexapac-ethyl at two rates, and diquat; and seed rate treatments included a high and low rate of a mixture of `Seville' perennial ryegrass (Lolium perenne L.) and `Sabre' rough bluegrass (Poa trivialis L.). The plot was maintained under golf course conditions and a traffic simulator was used to simulate golfer traffic. Visual ratings of percent green bermudagrass coverage were taken every 3 weeks from 20 Feb. 1997 to 29 July 1997 and from 11 Nov. 1997 to 22 July 1998. Visual turfgrass quality ratings were taken during the second year of the study. Results showed that spring transition was not influenced by fall-applied treatments during both years. Also, visual turfgrass quality was not influenced during the second year. Chemical names used: [4(cyclopropyl-αhydroxy-methylene) -3,5-dioxocyclohexanecarboxylic acid ethyl ester (trinexapac-ethyl); 9,10-dihydro-8a-, 10a-diazoniaphenanthrene (diquat).

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Robert L. Green, Grant J. Klein, Francisco Merino and Victor Gibeault

Bermudagrass [Cynodon dactylon (L.) Pers × C. transvaalensis Burtt-Davy] greens across the southern United States are normally overseeded in the fall to provide a uniform green playing surface and tolerance to wear during winter bermudagrass dormancy. The spring transition from overseed grass back to bermudagrass is a major problem associated with overseeding because there can be a decline in putting green quality and playability. There have been recommendations, but relatively few published reports, on the effect of treatments associated with seedbed preparation and overseeding on bermudagrass spring transition. The objective of this 2-year study was to determine if spring transition of an overseeded `Tifgreen' bermudagrass green was influenced by fall-applied scalping level, chemical, and seed rate treatments. Treatment factors and levels were designed to reflect the range of practices used by golf course superintendents in the region at the time of the study. The green was located in the Palm Springs, Calif. area, which has relatively mild winters and a low desert, southern Calif. climate. The first year of the study was from September 1996 to July 1997 and the second year was from September1997 to July 1998. Scalping level treatments included a moderate and severe verticut and scalp; chemical treatments included a check, trinexapac-ethyl at two rates, and diquat; and seed rate treatments included a high and low rate of a mixture of `Seville' perennial ryegrass (Lolium perenne L.) and `Sabre' rough bluegrass (Poa trivialis L.). The plot was maintained under golf course conditions and a traffic simulator was used to simulate golfer traffic. Visual ratings of percent green bermudagrass coverage were taken every 3 weeks from 20 Feb. 1997 to 29 July 1997 and from 11 Nov. 1997 to 22 July 1998. Visual turfgrass quality ratings were taken during the second year of the study. Results showed that spring transition was not influenced by fall-applied treatments during both years. Also, visual turfgrass quality was not influenced during the second year. Chemical names used [4(cyclopropyl-_hydroxy-methylene)-3,5-dioxocyclohexanecarboxylic acid ethyl ester (trinexapac-ethyl); 9,10-dihydro-8a-, 10a-diazoniaphenanthrene (diquat).

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Robert L. Green, Laosheng Wu and Grant J. Klein

Summer decline of annual bluegrass (Poa annua L.) putting greens is a major concern of golf course superintendents. Low soil water infiltration rates and high concentrations of salts in the root zone are contributing factors. This study was conducted to determine the effects of summer cultivation treatments on field infiltration rates of water, soil salinity, oxygen diffusion rates (ODR), bulk density, total and air-filled porosity, and root weight density. This research was conducted during two summer seasons (1996 and 1997) on a practice putting green located at Industry Hills Golf Courses, City of Industry, Calif. The green was constructed to U.S. Golf Association (USGA) specifications in 1978. Cultivation treatments consisted of: 1-3) water injection cultivation (WIC) applied with a Toro HydroJect every 21 d (raised position), and every 14 or 21 d (lowered position); 4) solid tine cultivation (STC) applied every 14 d; and 5) no cultivation (check). Results showed WIC and STC significantly increased field infiltration rates of water and lowered overall soil electrical conductivity of the extract (ECe) at depths of 2.5 to 7.5 cm and 7.5 to 15.0 cm in the root zone. The effects of WIC, raised position, did not differ significantly from those of STC, but infiltration rates of water were greater on all rating dates. Cultivation treatments had no significant effects on overall soil ODR, bulk density, and porosity or on overall root weight density.