• Comparison of Two Rates and Two Formulations of Imazaquin for Control of Purple Nutsedge

      Kopec, David M.; Jensen, D. P.; Gilbert, Jeffrey J.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Purple nutsedge (Cyperus rotundus) is a major warm season weed in turfgrass, landscape and agricultural settings. It’s long term persistence is achieved in part by (1) the production of tubers with numerous growing points (2) the ability to produce multiple plants from basal bulbuls at the soil level and (3) the tolerance to defoliation and/or soil cultivation. In turf, purple nutsedge can tolerate almost any mowing regime, and is competitive (in it's growth habit) with turfgrasses. Imazaquin (IMAGE) herbicide has been commercially available in the turfgrass market for almost 12 years for use in warm season turfgrasses for the control of purple nutsedge. Research conducted in the late 1980's at the University of Arizona showed that Image (EC formulation) provided adequate control of purple nutsedge when (1) multiple applications were applied 25 days apart (2) at the 0.50 lb. ai./a rate. In this scenario 98% nutsedge control was achieved (on 100 % nutsedge plots, mowed weekly at 2.5 inches). Repeat applications were still necessary after regrowth (presumably from growing points from underground nutlets). These results were achieved using the 1.5 EC (emulsifiable concentrate formulation). A new test was conducted in 1999, evaluating both the 1.5 EC and 70 DG (dispersible granule) formulations applied at two rates (0.375 lb. ai./a. and 0.50 lb. ai./a). Mean percent weed control on the three evaluation dates of August 17, August 29 and September 16 ranged from 25% to 32%, 50% to 68% and 55% to 75%, respectively. These dates represent the time intervals of 18 DAT/1, 30 DAT/1 and 17 DAT/2. On all three evaluations dates (where measured), the degree of injury, color and percent nutsedge infestation level was significant for the overall "treatment" effect at P=0.05, or less. (Tables 1,2). Actual percent weed control (based on the mean of control plots) was significant on August 29 (30 DAT/1) and on September 16 (17 DAT/2:47 DAT/1). Maximum weed control of 75% was achieved by the EC @ 0.50 lbs. ai./a. at 17 days after the second application. Percent weed control for the DG @ 0.50 lbs. ai./a. was greatest (61%) at that time also.
    • Control of Wild Celery in Low Maintenance Bermudagrass Turf.

      Kopec, David M.; Jensen, David M.; Gilbert, Jeffrey J.; Liddel, Steven B.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Herbicides applied for post-emergence control of wild parsley differed in turf injury and weed control. All products tested required multiple applications (21 days apart) to attain acceptable weed control levels. Weedone (2, 4-D) has the quickest, highest, and longest lasting amount of weed control. Weedone (2, 4-D) caused minimal injury to the common bermudagrass turf. Bromoxynil at the low rate of 2.0 lbs. ai/a caused minimal injury to the turf, but provided low levels of weed control. Bromoxynil at the high rate of 3.0 lbs. ai/a caused considerable injury to the turf and moderate to high weed control for about one month, followed by weed recovery. MCPP caused slight initial injury to common bermudagrass and moderate to good weed control (71%-92%) from 7 to 35 days after the second treatment. Weed control was slower to achieve than that of the Weedone treatments. Confront herbicide (trichlopyr and clopyralid) caused slight to moderate initial injury to the turf (more so at 2.0 than at 1.0 pint/product/acre) as well as noticeable necrosis and decreased color of the common bermudagrass up to 21 days after the second application. Confront at the 2.0 pint/acre rate reached weed control levels of 90%-97% at 21 and 35 days after the second application, respectively. At the low rate of 1.0 pint/acre, a maximum of 83% weed control was achieved at the close of the test. Quadmec (applied three weeks later at each respective application date than all other treatments) produced moderate necrosis in the bermudagrass after the initial application, which eventually recovered. However, the turfgrass color was lower in rank (lighter) than most other treatments and was similar to that of the untreated controls. Quadmec achieved 96% control by the close of the test on July 2, 1999 (14 days after the second application). All treatments include 0.5% v/v Silwet surfactant. When applied alone, Silwet produced a small level of weed control, which peaked at 36% at 14 days after the second treatment.
    • Creeping Bentgrass Turf Responses to Summer Applied Fungicides

      Kopec, David M.; Gilbert, Jeffrey J.; Jensen, D. P.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Creeping bentgrass is seasonally stressed from high summer temperatures and high humidity conditions in the desert southwest from June to mid-September. Golf greens typically show decreased stand density and poor performance by the end of this time. A preventative fungicide application program was evaluated for the prevention of summer stress typical under summer conditions. Four tank mixes composed of Alliete Signature mixed with either Chipco 26019, EXP10790A, EXP10702B, or Daconil Ultrex fungicides were applied every fourteen days from June 10 to September 17, 1997, on a 'Penncross' creeping bentgrass green maintained at 5/32". The Daconil Ultrex tank mix caused some initial injury and in general, the lightest turfgrass color and the lowest turfgrass quality. EXP10702B treated turf produced, on average, the darkest turf with the leading rank score for quality. The Chipco 26019 tank mix produced the largest seasonal clipping totals, which was greater than the check. No diseases occurred on treated or untreated turf. Root dry weights in mid-October varied as much as 40% among treatments, but was not statistically significant.
    • Cultural Management for Height Reduction of Tifgreen 328 Bermudagrass Greens

      Kerr, Darren E.; Kopec, David M.; Ruhl, Todd E.; Gilbert, Jeffrey J.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Tifgreen bermudagrass (328) has been used for greens in the Southwest for 40 years. Decreased mowing heights desired for tournament events can result in loss of turf quality and performance. A series of mowing and rolling events were devised and executed on a Tifgreen turf mowed at 5/32", in order to minimize the potential negative affects of a reduced mowing height of 1/8". All treatments were executed prior to mowing the turf at the new reduced height of 1/8". Significant treatment effects resulted from combinations of mowing and rolling for ball speed distance, when averaged over three evaluation dates. When averaged over all three evaluation dates, the single mow/no roll treatment [1x mow/0 roll] had the least ball roll distance (BRD) values. Mowing/rolling combinations which resulted in either three or four operations on Day 1 (1x mow/2x roll, 2x mow/2x roll and 2x mow/1x roll) had slightly greater BRD values than the operations which included two operations (2x mow/0x roll and 1x mow/1x roll). BRD values decreased from Day 1, Day 2 and Day 4 from 81.2", 80.3" to 73.4", respectively when average over all treatments. Single mowing at 5/32", followed by either a double or single rolling event prior to mowing to the new height of 1/8" on Day 1, resulted in the longest BRD values for Days 1 and 2. The effect of all cultural management treatments was diminished by Day 4.
    • Dimension Herbicide as a Potential Product for Pre-Emergence Pos Annual Control on Overseeded Bermudagrass Turf

      Kopec, David M.; Gilbert, Jeffrey J.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Dimension herbicide (dithiopyr) was applied to common bermudagrass turf at 90, 60, and 45 days before fall overseeding to measure the efficacy for turf safety and for control of fall germinating POA Annua (PA). Applications were made at 0.25, 0.375, and 0.50 lbs. AI/A on each date. One half of each plot was overseeded, while the other half was not. Percent plot (PA) infestation and percent weed control was more greatly affected by the process of overseeding, than that of the herbicide applications alone. When not overseeded, the bermudagrass turf had a maximum of 45% PA control in November, which decreased dramatically to little or no control from January to March 2000. With the inclusion of ryegrass overseed, the high rate (0.50 lbs. AI/A) applied closest to the overseeding (45 DBOS) provided between 79-82% PA control over the length of the test. Actual infestation levels among non-chemical receiving control plots showed a 3X increased level in PA suppression due to overseeding, when compared to the non-overseeded, non-chemical controls. Dimension herbicide alone had little effect for PA control. When combined with overseeding, the 0.50 lb. AI/A rate, applied at 60 or 45 DBOS provided the greatest levels of PA control. The performance of Dimension on non-overseeded bermudagrass does not support the anticipated use of this chemical for PA control.
    • 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.
    • The Effects of Pre-Emergence Applications of Sulfentrazone Herbicide and Perennial Ryegrass Overseeding of Poa annua Infestation of Winter Turf under Desert Conditions

      Kopec, David M.; Gilbert, Jeffrey J.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Poa annua or annual bluegrass is a cosmopolitan winter annual weed in turfgrass systems. A field test was conducted to evaluate the effects of sulfentrazone herbicide, both with and without the fall overseeding practice on bermudagrass in the desert. Sulfentrazone was applied three days before overseeding at 0.125, 0.187, 0.25, 0.375, 0.5 and 0.625 lbs.AI/A. Percent Poa infestation levels were dramatically less on overseeded (perennial ryegrass added) turf throughout the entire test period than non-overseeded (dormant bermudagrass) turf. For non-overseeded turf, sulfentrazone provided a maximum of 74% weed control at November 1997, 68% in December, and 25% by March 1998 at the highest application rate of 0.625 lbs./A. For overseeded (perennial ryegrass) turf, the highest level of weed control was achieved for sulfentrazone at the 0.625 lbs./A rate, which was 68% in April. The practices of overseeding and sulfentrazone applications provided the greatest weed control, however, different rate/timing regimes should be investigated to increase efficiency.
    • Ethephon Potential for Spring Transition of Perennial Ryegrass back to Common Bermudagrass

      Kopec, David M.; Jensen, D. P.; Gilbert, Jeffrey J.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Spring transition of ryegrass back to the underlying bermudagrass has become problematic for turfgrass managers in the Southwest. This is in part do to increased heat tolerance and shoot densities of newer ryegrass cultivars which predominate the market place. The chemical ethephon (Proxy for turf) was evaluated for use as a plant growth regulator (PGR) to enhance transition from perennial ryegrass to bermudagrass. Proxy was applied at either 5 or 10 ounce rates/1000 square ft, either before, during or after soil moisture stress was imposed on the overseeded turf. On the dates of July 6, 21, 19 and August 9 the greatest visible difference occurred among treatments for percent bermudagrass. These responses were not not statistically significant, however. The greatest transition response was achieved (in general) from Proxy applied at 10 the ounce rate, when applied "pre-stress". This treatment combination generally ranked highest for percent bermudagrass throughout the test. The second most beneficial treatment (in general) was that of Proxy at the 10 ounce rate when applied under "medium stress". From July 21 to August 9 this treatment essentially ranked second for the ryegrass to bermudagrass transition. The third most beneficial treatment (in general) was Proxy applied at the 10 ounce rate , applied "post stress". This treatment was applied the latest in the season ( June 16), which was 22 days after the entire test was fully irrigated (at the start of the test on May 23). Proxy applied "post stress" at the 10 ounce rate excelled in enhancing the ryegrass to bermudagrass transition from July 21 to July 29. When applied at either the 5 or 10 ounce product rates, the "low stress" application treatments had minimal affect for transition. These treatments ranked similar in response to that of the untreated - well watered controls. The "medium" stress plots receiving Proxy exhibited a greater affect on the ryegrass to bermuda transition, depending on the date of bermudagrass evaluation. Further testing should be conducted on lower mowed perennial ryegrass with a more aggressive underlying bermudagrass base, such as the popular Tifway 419.
    • Evaluation of Proxy and Primo for Growth Reduction in Perennial Ryegrass

      Kopec, David M.; Jensen, D. P.; Liddell, Steven B.; Gilbert, Jeffrey J.; Marcum, K. B.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      PROXY (ethephon) and PRIMO (trinexepac-ethyl) were applied to ryegrass (as overseeded turf) in winter and early spring of 1999. PGR effect was assessed as reduction in clipping weight between mowings on eleven harvest dates. From March to April, the greatest percentage reductions were realized from all PGR treatments. Over the entire test period (March 5 to May 15), clipping reduction was rate dependent for PROXY with the 10.0 ounce rate producing a greater PGR effect (less clippings than that of PROXY at the 5.0 ounce rate). PRIMO treated turf (at the highest label rate of 1.0 ounce/product/1000 ft) generally produced the greatest clipping reductions, but lost affect in the middle of May when suppression (broke) was released. PROXY at the 10.0 ounce rate was closer to that of PRIMO for PGR effect than was PROXY at the 5.0 rate. All treatments produced less clippings than that of the control on nine of the eleven harvest events. PRIMO produced on average a noticeably darker color turf than PROXY treated turfs and that of the control plots as well. PROXY treated turf at the 10.0 ounce rate generally had similar overall quality turf when compared to PRIMO treated turf throughout the test. This was due to a high degree of plant uniformity among PROXY treated turf, versus the darker color enhancement realized from PRIMO. No PGR affected the initial stages of spring transition from ryegrass to bermuda by late May 1999.
    • Evaluation of Timing Applications of Ethephon and Trinexepac-Ethyl for Seed Head Suppression of Poa annua

      Kopec, David M.; Gilbert, Jeffrey J.; Pessarakli, Mohammed; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Seed head production from Poa annua is problematic on winter turfs, whether they are overseeded or not. Flowering culms are unsightly, prevent a uniform surface, and insure a continuous crop of seeds for the future. A field test was conducted to evaluate the effects of PROXY and a PROXY/PRIMO PGR tank mix for seed head control. Treatments were applied on three different dates in order to evaluate the degree of response of treatments and help define treatment window applications for future programs. PROXY when applied alone at 5 ounces/product/M produced a maximum of 60% seed head control at 26 days after a single application on February 15, and 83% seed head control at 27 days after a single application on March 1. A tank mix of PROXY/PRIMO (5.0/0.25 ounces/product/M) generally produced greater seed head control than PROXY alone. The tank mix produced seed head control effects quicker, greater, and longer than PROXY alone. Seed head suppression and percent seed head control was greatest when products were applied initially on either February 15 or March 1, 2001. PROXY/PRIMO produced the darkest color turf when applied on either February 15 or March 1. At least three tank mixes seem to be needed, applied monthly to suppress/control seed heads throughout the winter/spring season.
    • 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 #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.
    • 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.
    • 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.
    • 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.
    • 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.
    • Green-Up of Dormant Bermudagrass after Applications of Early Spring Pre-Emergence Herbicides

      Kopec, David M.; Gilbert, Jeffrey J.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001-09)
      Six treatments of pre-emergence herbicides were evaluated for their effects on the spring green-up of dormant non-overseeded bermudagrass turf. Plot composition (percent yellow, percent green, percent straw or dormant turf) components were affected by herbicides to various extents on March 27, April 20, and April 27. Percent plot yellow turf was least in occurrence for BARRICADE, PENDULUM, and SURFLAN at 25 days after the first treatment. At 25 days after the first application (March 27) PENDULUM produced the lowest amount of green turf (13%) among treated turfs. At 50 days after the first application (April 20) PENDULUM treated turf had the greatest amount of yellow turf (63%), and the least amount of green turf present (18%). Turfgrass color was affected by herbicide treatments (on June 2, 30 days after the second treatment). The TEAM-PRO product had the darkest noticeable turf at this time. Herbicides had no affect on: A) visual estimates of turfgrass density B) number of lateral (horizontal) green stolons in the turf mat C) number of subterranean rhizomes D) root pegging of surface stolons. Green-up responses were short-lived from the herbicides evaluated at product rates tested.
    • 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.
    • 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.
    • 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.