• An Update on Termiticide Degradation in Arizona Soil

      Baker, Paul B.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Termiticide applications are the standard practice in the pest control industry to protect structures from the invasion of termites. However, information related to termiticide persistence is lacking. In 2 field trials, soil residues analysis were carried out to determine degradation among existing and candidate termiticides in 3 different chemical classes. Plots were established to simulate industry standards for the application of termiticides. Study 1 termiticides tested were Dragnet FT (permethrin, 0.5% and 0.25%;), Prevail FT (cypermethrin, 0.25%;), Biflex FT (bifenthrin, 0.06%;), Fury TC (zeta-cypermethrin, 0.125%;) Premise 75 (imidacloprid, 0.05%,), Dursban TC (chlorpyrifos, 1% and 0.75%) and the untreated check. In Study 2 termiticides tested were DeltaGard SC (deltamethrin 0.075%, 0.125% and 0.25%); Dragnet FT (permethrin 0.5%;)and the untreated checks. In study 1, in general, all termiticides showed more degradation in the exposed plots than those covered by the concrete slab. In the exposed plots, specifically in the 4th year, four of the eight treatments had no residues In comparison, the covered plots had only 1 treatment, with no residues. In general the pyrethroids of permethrin at 0.25% and 0.5% along with bifenthrin at 0.06% held up longer than the organophosphate chlorpyrifos or imidacloprid the chloronicotinyl compound. Study 2, after one year, the exposed plots showed a slightly greater degradation than the covered plots. However, due to plot-to-plot variation no conclusions can be drawn from the data, other than the permethrin plots showed less than 40% remaining in any plot.
    • Seed Propagation of Cordia boissieri and Cordia parvifolia

      Schuch, Ursula K.; Davison, Elizabeth; Kelly, Jack; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Cordia boissieri and Cordia parvifolia are plants commonly used in landscapes in the Southwest. Although they are available in the nursery trade, Cordia species are recalcitrant to germinate from seeds. The objective of the study was to determine a reliable propagation protocol for each species. Germination percentages for Cordia boissieri of 70 to 100% were obtained when seeds were stratified under warm conditions before germination. However, with prolonged storage seeds lose viability and age of the seed and seed storage conditions need further investigation. Seeds of Cordia parvifolia collected from local sources had low viability and did not germinate in response to several different seed treatments.
    • Drought Tolerance of Twenty one Saltgrass (Distichlis) Accessions Compared to Bermudagrass

      Pessarakli, Mohammed; Marcum, K. B.; Kopec, David M.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Fourteen (14) Arizona accessions and 7 Colorado accessions of Saltgrass (Distichlis spicata), collected from Arizona and Colorado and 1 Bermudagrass (Cynodon dactylon), cultivar Midiron (check), were studied in a greenhouse to evaluate their growth responses in terms of shoot dry weights and percentage of visual green under drought stress conditions. Plants were grown under normal (daily watering and weekly fertilizer application) for one year for complete establishment. Then, the plants were deprived from water for four months (January 5, 2001 - May 5, 2001). Plant clippings were harvested weekly, oven dried at 60 °C, and the dry weights were recorded. At each harvest, percentage of green cover were also estimated and recorded. After the last harvest, plants were re-watered to assess and compare the percent of recovery. Overall, the results (both shoot dry weights and the percent of the visual green) show that the A138 and A137 (Arizona accessions) were the best accessions and the C66 (Colorado accession) was the worst. Both the shoot dry weights and the percent of visual green cover decreased as the drought period progressed. In general, most of the saltgrass accessions were more tolerant to drought stress than the bermudagrass.
    • Overseeding Fairway Trials

      Kopec, David M.; Gilbert, Jeffrey J.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Fifty-one overseed entries were evaluated in 1997-1998 for turfgrass performance. New experimental accessions of perennial ryegrass were darker in color than most of the commercially available germplasm included in this test. Ryegrass germplasm had better turfgrass quality after April, than did mixtures of perennial ryegrass with Poa trivialis, which performed well in December, January and March. General appearance for total plot leaf texture was best generally among the Poa trivialis containing mixtures. Hybrid (or intermediate) ryegrasses (L. which are crosses between perennial X annual ryegrass, are generally closer to annual ryegrass in performance. There was a vast improvement in L. hybridum (Pick YNC) when compared to annual ryegrass alone for turf performance. Intermediate and annual ryegrasses did show signs of decline in June (more so than ryegrass or Poa trivialis blends), which was desirable from a transition standpoint.
    • Field Performance of Selected Mowed Distichlis Clones, USGA Research Report #1

      Kopec, David M.; Marcum, Kenneth P.; Hughes, Harrison; Christiansen, Dana; Koski, Anthony; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Twenty-one clonal selections of saltgrass (Distichlis) were evaluated in March and May for initial green-up, plot growth, unmowed canopy height, number of satellite plants emerging from rhizomes and floral expression. Accessions were statistically different for all variables measured. Colorado’s accessions (5 of 7) were upright in growth habit and had the greatest number of satellite plants at the surface in March. These plants also had the greatest percent plot coverage. Arizona’s accessions had lower growth in height, were more compact in growth and were less sprawling. However, their plot coverage (grow-in) was not as great as the upright, rapid growing Colorado accessions. Of the twenty-one clones included, thirteen are males and eight are females, with expression ranging from 1 to more than 200 flowering culms per plot.
    • Response of Poa annua to Post-Emergence Application of Sulfentrazone Herbicide

      Kopec, David M.; Gilbert, Jeffrey J.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Poa annua (annual bluegrass) is a major weed problem in winter turfs. It is a cosmopolitan and well adapted weed in most turfgrass settings. Cultural management programs to control or eliminate Poa annua are either limited or unsuccessful. Sulfentrazone herbicide was applied to perennial ryegrass turf (as overseeded bermudagrass) which had high levels of Poa annua infestation (45%-75%) at 0.125, 0.250 and 0.375 lb. AI/A. There was essentially a limited response of Poa annua to Sulfentrazone at these rates when applied on March 7, 1997. EMBARK LITE (Mefluidide) was applied once at 0.125 lb. AI/A and caused some initial discoloration to the turf at 10 DAT. At 25 DAT percent control of Poa annua (seed heads) reached 90% or greater which declined to 58% on April 15 (40 DAT). Turfgrass color was enhanced from the single application of Mefluidide at 25 and 40 DAT on golf course rough turf maintained at a mowing height of 1.50 inches. Sulfentrazone exhibited minimal or no effect on Poa annua when applied as a post emergence treatment.
    • Influence of pH 11 Water on Termiticide Degradation in Arizona

      Baker, Paul B.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Termites continue to be Arizona’s number one urban pest. Factors that influence the persistence of termiticides are constantly under investigation. High pH has been identified as a potential concern for persistence in termiticides. I studied the influence of pH 11 water on five termiticides applied to commercial ABC fill 10 months post-treatment. In general, the addition of pH 11 water had little influence on termiticide persistence under Arizona conditions. Initially plots treated with Ph 11 water had higher residues than those that did not receive the treated water; over time these differences diminished.
    • Sulfentrazone Effects on Purple Nutsedge

      Kopec, David M.; Gilbert, Jeffrey J.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Sulfentrazone was applied to a highly infested purple nutsedge groundcover as either single or double combination (split) applications for initial evaluation for weed control during the summer of 1996. One time single applications at 0.125 lb. AI/A resulted in 15% or less control, from 10 to 64 days after treatment (DAT). Nutsedge control from 0.25 lb. and 0.38 lb. AI/A treatments were not significantly different from each other (ranging in 10% difference or less) but was greater than the low rate 0.125 lb. AI/A. Single applications of imazaquin and halsulfuron (at known label rates) had better control than sulfentrazone at the rates tested here when tested as single applications. Single applications at 0.50 lb. AI/A appear warranted for sulfentrazone. Split (multiple) applications greatly enhanced the activity of Sulfentrazone at the two higher split rate treatments, both which resulted in a total application of 0.50 lb. AI/A total. The 0.375/0.125 split application had slightly better control than the 0.250/0.250 split treatments. Split applications of imazaquin or halsulfuron at known label rates resulted in slightly higher control. All plots experienced re-growth. Based on these results, sulfentrazone does have activity against purple nutsedge. Additional treatments in a new and different rate structure appear warranted to increase initial control and longevity of effect.
    • Spring Transition of Tifway (419) Bermudagrass as Influenced by Herbicide Treatments

      Kopec, David M.; Gilbert, Jeffrey J.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      The transition from perennial ryegrass back to bermudagrass is often problematic. Prolonged periods of ryegrass persistence and/or loss of complete turf is troublesome and not favorable to the reestablishment of the bermudagrass base. A group of select herbicides were applied in May 2000, to assess their response to enhance the removal of perennial ryegrass, and to enhance recovery of the bermudagrass. CORSAIR (Chlorosufuron) applied at 1.0 ounce/product/acre resulted in reduced turfgrass quality from three to six weeks after treatment, with a decrease in color at three weeks. This treatment caused moderate suppression of the turf and an enhanced transition from perennial ryegrass to Tifway (419). MANOR (Metsulfuron) applied at 0.4 ounce/product/acre caused a slight growth suppression, acceptable turfgrass color, but a noticeable decrease in turfgrass quality up to six weeks after application. MANOR increased turf density and minimized scalping by seven weeks after treatment (July 24, 2000). SURFLAN when applied at 1.5 lb AI/A, produced acceptable quality turf, no visible growth suppression, acceptable overseed turf quality and color. SURFLAN did not provide any affect as a transition agent in this test. KERB did not greatly enhance transition, and was slightly more effective at 0.5 lb AI/A, than at the 1.0 lb AI/A rate. Both rates of KERB produced acceptable turfgrass color throughout the test. Turfgrass quality diminished to low levels from July 18 to July 24, ranking lowest in quality. KERB treated turf tended to "scalp" more than other treated turfs and thinned the grass at the high rate of 0.50 lb AI/A. FIRST RATE applied at 75 grams AI/hectare caused slight visible suppression for two weeks after treatment, an acceptable quality turf (on six of seven evaluation dates), acceptable turfgrass color and turf density. FIRST RATE did enhance transition, but less so than CORSAIR, possibly less than MANOR, and certainly less than AEF 130630. PROXY was applied on four dates (four, three, two, and zero weeks prior to June 3), selected as a "calendar target" dates observe transition. PROXY when applied on May 13, provided a short transition effect, for a period of about two weeks. Applications made later had little effect whatsoever, on Spring transition back to bermudagrass. From May 19 to June 5, the two "early" applications of PROXY, generally increased turfgrass color and quality scores, most likely by having a PGR response on perennial ryegrass. AEF 130630 readily enhanced Spring transition from perennial ryegrass to Tifway (419) bermudagrass, especially in May and June. All three application rates caused visual suppression of the turf from May 19 until June 5. Turfgrass color and quality were affected by AEF 130630. The maximum expression occurred for the 0.42 ounce/product/M rate by May 25 (which remained until at least June 5). Mean color scores here were 5.3, on both dates. The high rate 0.64 ounce/product/M actually caused less color reductions in the turf (perhaps as a function of the quicker removal of ryegrass). Reduced turf quality resulted three weeks after treatment for both the low and high rates (means = 5.0). The turf was similar to that of the control plots, afterwards, and superior by both middle and late July time periods.
    • Oxadiazon Applied as a Pre-Emergence for Poa annua with Reference to Fall Overseeding of Bermudagrass Turf

      Kopec, David M.; Gilbert, Jeffrey J.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Ronstar was applied at three rates (1.0, 2.0 and 4.0 lbs. AI/A) at 12, 10, 8, 6 and 4 weeks before overseeding bermudagrass turf with perennial ryegrass on October 20, 1997. On November 7, 1997 (18 DAS) Ronstar treated plots ranged from 20% to 81% for percent plot ryegrass coverage. The greatest mean ryegrass coverage occurred for the 2.0 lbs. rate/@ 12 WBOS. Among the 4 lbs. treatments, there was more or less a linear decrease for ryegrass establishment on a visual plot basis as the application time came closer to the overseeding date. On December 1, Ronstar treated field plots ranged from a low of 29% ryegrass cover (4 lbs./@ 4 WBOS) to 91% (2 lbs./@ 12 WBOS). Among the 4 lbs. treated plots, the 10 and 12 WBOS timing allowed for 82% and 75% mean plot cover respectively, by December 1 (42 DAS). Of the remaining treatments, the 2 lbs./@ 4 WBOS had 61% plot cover (ryegrass) while all other 1 lbs. and 2 lbs. plots had 80% or greater cover at this time. On December 15, 1997 (56 DAS), mean percent plot scores for percentage ryegrass cover ranged from 53% to 100%. The only plot which had significantly less plot cover was 4 lbs./@ 4 WBOS (53%). All other plots had 88% or greater ryegrass cover. Turfgrass color scores showed a significant Atreatment@ effect on December 15, but not on December 29, January 29, March 11 or on April 11. On December 29 (70 DAS), overall turfgrass quality scores ranged from 4.0 (unacceptable) to 7.8. Two treatments which were sub-par included 4 lbs./@ 6 WBOS (5.7 = marginal) and 4 lbs./@ 4 WBOS (4.0 = unacceptable). Treatments which had mean quality values of 7.0 or higher included; 1 lbs./@ 10 WBOS (7.8), 1 lbs./@ 6 WBOS (7.8), 2 lbs./@ 10 WBOS (7.5), 1 lbs./@ 8 WBOS (7.3), 2 lbs./@ 6 WBOS (7.3), 4 lbs./@ 12 WBOS (7.3) and 2 lbs./@ 12 WBOS (7.3). Weed pressure was inadequate to fully assess pre-emergence control of Poa annua. At the close of the test on April 11, 1998, weed control ranged from 8% to 100%. Plots with 90% or greater weed control included 2 lbs./@ 10 WBOS, 1 lbs./@ 4 WBOS, and 4 lbs./@ 12, 8, 6, and 4 WBOS. The 1.0 lbs. AI/A treatment was safe for perennial ryegrass at 12, 10, 8, 6, and 4 WBOS. The 2.0 lbs. AI/A treatment was safe for perennial ryegrass at 12, 10, and 8 weeks. The 4.0 lbs. AI/A treatment was safe at 12 and 10 WBOS.
    • Field Performance of Selected Mowed Distichlis Clones, USGA Research Report #2

      Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Twenty-one clonal selections of saltgrass (Distichlis spp.) were evaluated during the first full summer growing season (May - October 1999) for turf characteristics and general adaptation. Initial percent plot cover in May ranged from 8% to 42% among clonal accessions. Accessions which produced the highest unmowed canopy heights had the greatest initial cover in May. This trend reversed itself by August and September whereby entries which exhibited less elevated foliage tended to produce turfs which had higher shoot densities, greater percent plot cover, visual estimates of density and more acceptable overall turfgrass quality under accumulated mowing pressure. The "treatment" (clonal accession) affect was significant on all dates for all field variables demonstrating clearly that differences exist for growth parameters of Distichlis screened under mowing stress.
    • Fairway Overseed Turfgrass Trials, 1996-1997 Season

      Kopec, David M.; Gilbert, Jeffrey J.; Kerr, Darren E.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Twenty-three overseed entries (and a non-overseed check) were evaluated from November 1996 to June 1997 for turf performance over Tifgreen (328) bermudagrass. Entries varied for turfgrass establishment, color, quality, density, texture and uniformity on all evaluation dates. One annual ryegrass and three intermediate ryegrass Lolium hybridium entries were included. The intermediate type 'Hybrid X-NC' had better performance than 'Froghair' or 'Hybredium' intermediate hybrids in most cases, except for early transition. Entries which consistently had the darkest green genetic color included 'Citation III', 'LPQ-N3', 'EP-20', 'Charger II', '84-91', 'WX-140', and 'Roadrunner'. Entries which consistently ranked high in overall turfgrass performance included 'Citation III', '2-DLM', '84-91', 'Roadrunner', 'Charger II', 'WX-140', '93-7', and 'LPQ-N3'.
    • Field Performance of Selected Mowed Distichlis Clones, USGA Research Report #3

      Kopec, David M.; Adams, Alan; Bourn, Chris; Gilbert, Jeffrey J.; Marcum, Kenneth P.; Pessarakli, Mohammed; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Twenty-one clonal (genotype) accessions of Distichlis are being continually evaluated for field performance as replicated mowed turf plots under desert conditions. The genotype ("treatment") affect was significant for most field variables measured, or assigned to plots using visual rating scales customary for turf evaluations. Genotype differences occurred for percent plot composition color, quality, texture, uniformity and leaf width. Visual stress (prolonged hot weather without irrigation) and leaf hair presence were not significant responses between accessions. Long term mowing stress shows divergent performance amount Distichlis germplasm for growth characters and turf persistence under mowed conditions.
    • Scotts Contec Fertilizer Study - 1998

      Gilbert, Jeff J.; Kopec, David M.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Three slow release fertilizers were evaluated (Contec O.M. Scotts) for turfgrass performance on an overseeded Tifway bermudagrass green from May to October 1998. Products were applied on four dates at the rate of 0.5 and 1.50 lbs. actual -N- per thousand square feet. All fertilizer regime showed little response from June-July for turfgrass clippings, color and quality. After July, differences in color and clippings were detected on X out of X evaluation dates. In general, release/conversion responses occurred approximately one month after application. When coupled with subsequent series applications, the combination of released nitrogen with the water soluble component (approximately 10%) caused the greatest turf response. Clipping production was greatest for the X at the rate of X. Transition from ryegrass to bermudagrass was not affected by fertilizer rate. Additional rates should be tested to investigate seasonal performance of these fertilizers on bermudagrass turfs.
    • Ryegrass Germplasm Overseeding Trials

      Kopec, David M.; Gilbert, Jeffrey J.; Jensen, David M.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      A field test was conducted to evaluate the turf performance of improved hybrid ryegrass (sometimes called intermediate ryegrass) Lolium hybridum versus that of perennial ryegrass germplasm (Lolium perenne) for winter overseeding purposes. "Gulf" annual ryegrass was also evaluated for comparison purposes. On all evaluation dates, the treatment effect was significant for all visual response variables measured (quality, color, texture, density, etc.). The mixture of LHRT hybrid ryegrass/Poa trivialis established quicker than other treatments during the first month (November). Perennial ryegrass entries provided the darkest color turf. Among hybrid ryegrasses, Pick A-97 was slightly darker in turf color when compared to LHRT. LHRT alone was darker in color than when mixed with Poa trivialis. In terms of overall turf quality, Pick A-97 and LHRT hybrid ryegrasses were essentially equal in performance. The spring decline was greater among hybrid ryegrasses than that of perennial ryegrass. Both hybrid ryegrasses (A-97 and LHRT) were superior to annual ryegrasses in all aspects of turf performance. By mid-June of 1999, Pick A-97 had more bermudagrass present (52%) than LHRT (28%). LHRT had more straw-colored (dead transition grass) than A-97 as well. By early July, A-97 and LHRT had 72% and 62% bermudagrass, respectively, and essentially the same amount of overseed present (20-23%). LHRT had 15% plot straw at this time, while A-97 had 8%. Among perennial ryegrasses, Sunshine had the slowest transition (42%), followed by Jiffie (50%) and Future 2500 (71%) by early July. The addition of Poa trivialis to LHRT hybrid ryegrass increased overall quality of the LHRT alone, but slowed transition slightly, most likely due to increased canopy densities achieved by the addition of Poa trivialis. This test demonstrated that the hybrid ryegrass germplasm tested here provided adequate fairway turf performance, and that transition among and between Lolium germplasm is variable, and genetically dependant.
    • Growth Responses of Desert Saltgrass under Salt Stress

      Pessarakli, Mohammed; Marcum, K. B.; Kopec, David M.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Saltgrass (Distichlis spicata), clonal accession WA-12, collected from Wilcox, Arizona was studied in a greenhouse to evaluate its growth responses in terms of shoot and root lengths, shoot fresh weight, and shoot and root dry weights under control and salt (sodium chloride) stress conditions. Plants were grown under control (no salt) and three levels of salt stress (100, 200, and 400mM NaCl equivalent to 6250, 12500, and 25,000 g Lᴮ¹ sodium chloride, respectively), using Hoagland solution in a hydroponics system. Plant shoots (clippings) were harvested weekly, oven dried at 60 °C, and dry weights recorded. At each harvest, both shoot and root lengths were measured and recorded. At the last harvest, plant roots were also harvested, oven dried, and dry weights were determined and recorded. The results show that the shoot and root lengths decreased with increasing the salinity levels, however, both shoot fresh and dry weights significantly increased at 200mM NaCl salinity compared with the control or the 400mM NaCl level. Root dry weights at both 200mM and 400mM NaCl salinity levels were significantly higher than the control.
    • Field Performance of Selected Mowed Distichlis Clones, USGA Research Report #4

      Kopec, David M.; Adams, Alan; Bourn, Chris; Gilbert, Jeffrey J.; Marcum, Kenneth P.; Pessarakli, Mohammed; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Clonal accessions (genotype selections) of Distichlis continue to show divergent responses for turf-type growth habit and general turf-type adaptation under field mowing stress. The treatment (clonal accession) affect was significant for all field response variables from mid July to mid August (data collections for Report #4, except for "percent plot straw" on October 12. In July 2000, mean percent plot green cover ranged from 47% to 96% among clonal accessions. Turfgrass quality in July was best among the entries A138, A86, A137, A48, A51, and A40. These entries had the greatest percent plot cover, moderately fine leaf texture, and high shoot density, compared to other entries. In the calendar year 2000, (includes weather conditions in Report #3), the test site was exposed to atmospheric conditions which included a reference ET. of 3.59" (January); 4.42" (February); 6.23" (March); 8.96" (April); 11.32" (May); 9.08" (June); 9.31" (July); 7.53" (August); 7.37" (September); 3.55" (October). The test was subjected to severe drought conditions throughout the test, starting April 2000. Rainfall from January too, and including April was 1.28 inches. There was no rain from May 1 to June 15. Four rains from July 17 to July 30 added 2.94 inches of rainfall, with two thirds of this occurring from one storm on July 29. No irrigation was added from July 1, until September 15. During that time period, 3.26 inches of rain fell in July. In August, 2.47" of rainfall occurred. From June 1 to September 15, the accumulated reference ET. was 29.68 inches. Total rainfall was 5.81" (no irrigation practiced). Most (but not all) Distichlis accessions maintained adequate turf color and percent plot green, up to late August. Visual stress ratings in early August showed differences in visual stress ratings and leaf canopy temperatures measured with a hand held IRT device. Entries A48, A51, A40, A138, A61, and C10 exhibited the least amount of visible drought stress in early August. Accessions that had the highest overall quality ratings in July were A138, A86, A137, A48, A51, and A40. Accessions that exhibited acceptable (highest) turf quality prior to and during the drought period included A138, A40, and A51. Drought induced dormancy finally occurred at the beginning of September, as most accessions drastically decreased the amount of green plot foliage after a prolonged period without irrigation. After flood irrigation and fertilizer applications on September 15 and September 29, plots recovered by mid October. The recovery was not full, as the greatest amount of green percent plot cover ranged from 23% to 83% among entries. Entries with the greatest amount of green cover after the post dormancy period included, A65, A138, A137, A77, and A72. All entries did exhibit reduced quality in comparison to July ratings. Based on these results, Distichlis should be irrigated once/month in a desert condition to avoid drought induced dormancy. During the calendar year 2000, accessions which had notable performance included: Early Spring Green Up: C8, A77, A138, A86; Early Summer Quality (non-water stress in May, and water stressed in June): A55, A86, A51, and A40, A138; Mid Summer Quality: A48, A86, A137, A51, A138; During Drought Quality: A138, A40, A51; Post Dormancy Quality: A65, A138, A137, A77, A72.
    • Overseed Greens Trial 1997-1998

      Kopec, David M.; Gilbert, Jeffrey J.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Perennial ryegrass germplasm was quicker to establish plot cover on a "Tifgreen" bermudagrass green than that of Poa trivialis when used alone. Poa trivialis alone produced lighter color turfs when compared to perennial ryegrass. Turfgrass color was generally uniform in appearance, however, within each entry. Therefore, color as a selection criteria is a matter of choice by the user. The turfgrass mixture "Catalina/Winterplay" (80% perennial ryegrass/20% Poa trivialis) was intermediate in turfgrass color. "Brightstar II" PR generally produced a dark turf throughout the growing season. For overall turfgrass quality, the perennial ryegrasses generally out performed the Poa trivialis germplasm. The mixture of "Catalina/Winterplay" produced a very dense turf, followed closely by "Turfstar Plus" PR, "95-1" PR and "PT-4" PT. ASnowbird@ PT had the least amount of living ground cover by May 31, which is desirable from a transition standpoint.
    • Forced Transition of Tifway 419 using Select Cultural Management Practices

      Kopec, David M.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      A test was devised to investigate a forced spring transition from perennial ryegrass, back to Tifway (419) bermudagrass with scalping as the main treatment. Scalping of the turf was combined with various nitrogen and aerification treatments performed initially on May 22, 1997. Turfgrass aeration, either with or without extra nitrogen applications, when combined with an initial scalping operation, did not enhance bermudagrass transition by twenty-eight days after treatment (DAT), at the end of June 1997. Turfgrass color, quality and density were adversely affected from initial aerification treatments, especially when combined with initial scalping, The turf recovered best from multiple applications of nitrogen (applied at scalping and again at 7DAT). Turfgrass density (visual estimates) showed that in conjunction with scalping, two applications of nitrogen, totaling 1.5 lbs./month, without aerification, provided a dense turf at 16DAT, which was second only to the untreated control plot. At 27 DAT, scalping + N + N + aerification treated plots had the highest estimate of visual density, eventually showing a benefit from aerification. Scalped and aerified turf alone (no nitrogen) had unacceptable turf density at 16DAT and 27DAT. Generally, two 0.75 lb./N/m applications with aerification proved beneficial over the single application of nitrogen plus aerification, when both turfs were initially scalped. Although non-significant statistically, the additional treatment of nitrogen provided 10% more bermudagrass cover than the single application of nitrogen, for turfs both overseeded and scalped. Scalping alone, plus a single application of N, produced 33% less bermudagrass by June 30, then that of the untreated control.
    • Initial Investigations of Effectiveness of Cultural Practices to Minimize the Negative Effects of Excessive Thatch on SR1020 Creeping Bentgrass

      Whitlark, Brian S.; Jensen, David; Kopec, David M.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Increased demand for golf course greens with fast ball speeds and aesthetically pleasing turf present the greatest public pressures that golf course superintendents face today. In the desert southwest, the annual summer monsoon rainfall pattern brings increased atmospheric humidity which results in an increase in the tendency of SR1020 creeping bentgrass to build-up thatch. The effects of four different cultural practices on color, quality, thatch, and ball roll were evaluated on a SR1020 creeping bentgrass green built to USGA specifications grown in an arid environment during a period of increased atmospheric humidity and rainfall. Plots that were verticut/topdress once every two weeks showed unacceptable color, quality, and ball roll. Rolling twice a week had no significant impact on color, quality, and thatch, however, rolling did have a slightly positive impact on ball roll. Grooming three times per week had no significant impact on thatch reduction, and resulted in decreased color, quality and ball speed. Topdressing one time per week did decrease the natural tendency of thatch build-up in SR1020 during periods of increased atmospheric humidity. Topdressing one time per week slightly increased color, quality, and ball roll.