• 1988 Tall Fescue Variety Trial

      Mancino, C. F.; Kopec, D. M.; Salo, L.; Bermudez, R.; Kopec, David M. (College of Agriculture, University of Arizona (Tucson, AZ), 1988)
    • 1989 Tall Fescue Variety Trial

      Mancino, C. F.; Kopec, D. M.; Ralowicz, A. E.; Maricic, A.; Nelson, D.; Kopec, David M. (College of Agriculture, University of Arizona (Tucson, AZ), 1989)
      Tall fescue is a very heat and drought tolerant, cool season turf, which can remain green throughout the year in the arid Southwest. Data are lacking on the performance of tall fescue varieties in this location. Sixty-five tall fescue entries were established in November 1987 and their performance as a home-lawn turf rated for quality, color, density, percent ground cover, pest incidence and water use. All varieties performed very well during the first seven months of 1989, but a decline in August quality was observed during summer monsoons mainly due to the incidence of large brown patch (Rhizoctonia solani L.) and record-setting high temperatures. Turf still showed signs of stress by mid-September. Turfgrass irrigation water use from 1 January to 23 September totalled 43.3 inches (1100.5 mm) and averaged 63 % of predicted evapotranspiration.
    • 2002-2003 Overseeding Turf Trials

      Kopec, David M.; Gilbert, Jeff J.; Pessarakli, Mohammed; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
      Sixty-four overseed turf entries were evaluated from October 2002, to June 2003 for turf when overseeded on Tifway bermudagrass fairway turf. Overseed entries included 43 single variety (or experimental synthetics) of perennial ryegrass, 2 annual ryegrasses, 6 entries of intermediate or 'hybrid' ryegrass, 5 entries of Poa trivialis (PT), one blend of perennial ryegrass, 4 mixtures (two or more species together) and 3 fescues. The main effect of "overseed grass entry" was highly significant on all dates for all visual turf responses, which included establishment, color quality, density, texture, and spring transition. The greatest amount of variation occurred within the perennial ryegrass group as a whole, showing the diversity within this species for overseeding performance. Annual ryegrass provided quick germination and ground coverage in the fall and a quick spring transition, but was of poor turf quality. Intermediate ryegrasses had performance values between that of perennial and annual ryegrass, some of which provided moderately good turf performance and good transition. Poa trivialis was slow to establish, but provided good quality and excellent plot texture, however they had poor transitional qualities. Final quality mean scores ranged from 3.0 (P-02-0047 PT) to 7.7. There were three entries, which averaged 7.7 at the close of the test, which included Mach 1 PR, SR 4500 PR, and Pace PR. The entries IG-2, Greenville PR, Express PR, Bar LO 2001, Hawkeye, Partee finished at 7.3 for quality. Among the intermediate ryegrass entries, Froghair finished with a mean quality score of 7.0, followed by Pick 00- A-LH (5.3). All three fescues produced mean quality scores of 6.0 or better on 8 June (Hardtop fescue leading at 6.7 for quality). The Labarinth tall fescue did have 62% Bermuda at the end of the test, compared to 65% for all entries at that time. Entries which had a mean quality score of 7.0 or more in June, along with a bermuda transition of close to 75% or more at the termination of the test included the following entries; Citation Fore, Mach 1, BarGold, Bar LP 2001, Pace, Greenville OSP, and Express.
    • 2006 2007 Fairway Overseeding Trials University of Arizona

      Kopec, David M.; Gilbert, Jeff J.; Pessarakli, Mohammed; Nolan, Steve; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2009-02)
      Forty nine seeded entries were overseeded into Tifway bermudagrass maintained at 5/8" inch. Improved annuals showed better turf performance in most categories than GULF annual, while hybrid(intermediate ryegrasses) showed great improvement over original release material. Annuals and hybrids were more vigorous in plot establishment after emergence until late November/early December, when perennial types increased plot cover. Poa trivilais was slower to emerge than other grasses, but had excellent performance in the coldest parts of the winter season, only to decline early in the spring for overall turfgrass quality. Turfgrass color scores were greatest on 17 February and 27 March. On 17 February, the mean color scores ranged from a low value for Gulf annual (4.0), to the Jacklin blend which averaged 8.5 (Table 3). Other darker entries included the PHD blend (8.0), B-5.1095 ryegrass (8.0), B-6.1523 ryegrass (8.0) Pick EJ ryegrass (8.0), B-6.1523 (8.0), Brea ryegrass (7.8), Pavilion ryegrass (7.8), RX ryegrass blend (7.8), Acapella ryegrass (7.8) Ringer II (7.8) and PM 102 ryegrass (7.8). Physical mowing stress was evident on 2 May, in which grasses exhibited leaf tip shredding and elongated flowering culms. Gulf and Panterra annual aul ryegrass showed the least favorable mowing response. STR 4NV (intermediate ryegrass ) had mow stress-type symptoms similar to perennial ryegrass, which was much less than that of the annual types. On 19 June, bermudagrass plot cover ranged from 17.5% (Laser PT) to 100% cover on several other entries. The Rx ryegrass blend, Bar LM TL annual ryegrass, Leaguemaster blend, and Heat PR all had 100% bermudagrass cover. The non-overseeded checks had 95% bermudagrass on 19 June. There were nine entries with 90% or more bermudagrass, ten entries that had 80-85% bermuda, four entries that had between 85-90% Bermuda, and sixteen entries with 75% or less bermudagrass on 19 June. The Champion Fine mixture had 55% bermudagrass. PHD had 63%. Pavilion had 63% bermuda as well. The Poa trivialis entries had the least amount of bermudagrass present. Entries which had high quality scores on average throughout the entire test period (early November to July 12 included the entries, Champion RB (mixture of creeping red fescue and perennial ryegrass) (6.8) ; Champion GC (mixture of fine fescue and perennial rygrass) (6.8) ; the experimental ryegrass B-6.1523 (6.7) ; Jackilin Blend A (6.7) ; the experimental ryegrass B-6.1091 (6.9) ; and B-6.0756 (6.8) ; Entries which had generally throughout the entire season had good quality and high amounts of bermudagrass on 19 June included Heat (100%), STR 4TPC (93%), STR 4QT (90%), RX (100%), Jacklin Blend A (88%), B-6.1095 (95%), and Champion STF (98%). Other entries had a quicker transition, but had lower mean quality scores otherwise, while others had high quality scores, but a slower transition.
    • Accumulation of Soil Salinity in Landscapes Irrigated with Reclaimed Water

      Schuch, Ursula K.; Walworth, James; Mahato, Tilak; Pond, Andrew; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2008-01)
      The long-term use of reclaimed water for landscape maintenance and the effects on soil chemistry and soil structure were investigated. Irrigation with reclaimed versus potable water for five years or more affects chemical properties of soil. Soils irrigated with reclaimed versus potable water had higher EC. Monsoon precipitation had less of a leaching effect than anticipated and significantly reduced EC only on two out of 13 sites. Soils irrigated with reclaimed water had higher SAR values than those irrigated with potable water and can potentially develop infiltration problems in the future. Contour maps of the EC for three depths of one site as measured by soil samples and EC as predicted by EM38 measurements for pre- and post-monsoon sampling times were developed.
    • Activity of Imazaquin for Purple Nutsedge Suppression Using Various Application Techniques

      Kopec, D. M.; Heathman, E. S.; Mancino, C. F.; Moharram, H. N.; Kopec, David M. (College of Agriculture, University of Arizona (Tucson, AZ), 1989)
      An experiment was devised to evaluate application technique, and elucidate the plant response (herbicidal activity) of imazaquin herbicide on single plants of purple nutsedge. Herbicide treated plants showed increased filleting and stunting 31 days after treatment. Soil treatments tended to increase herbicidal response. Imazaquin activity was minimized when the herbicide was not irrigated into the soil. Soil applied-imazaquin postponed the emergence of shoots from viable nutlets, but did not prevent emergence altogether.
    • AEF 130360 Overseeding Safety

      Kopec, David M.; Gilbert, Jeff J.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
      Several items need consideration when products are evaluated for use as transition agents. These are (1) efficacy of ryegrass removal [rate of ryegrass decline and appearance of turf during transition], (2) tolerance and performance of incoming bermudagrass and (3) application safety for next season’s repeat overseed operations. This test was designed to evaluate application safety for the next overseeding which occurs in the early fall. Therefore, AEF was applied in the summer to bermudagrass turf prior to overseed operations. Most responses of the perennial ryegrass (overseed) turf to previous treatments of AEF 130360 occurred immediately after overseeding, from mid-October to early November. AEF 130360 applied 2 weeks before overseeding caused a significant decrease in seedling vigor, percent plot ryegrass cover, and percent bermudagrass plot straw present. Both AEF treatments applied closest to overseeding (2 weeks prior) had the least amount of initial ryegrass, the greatest amount of green bermudagrass, and later in the season, the most amount of straw (dormant) bermudagrass. Differences in turfgrass quality were not significant due to treatments at any time throughout the test, and most treatments ranked higher than the control in overall quality. Under the conditions of this test, application of AEF 130360 at either 0.64 or 1.28 ounces/product/M made one month before actual oversseding did not cause detrimental effects to ryegrass emergence, ryegrass cover, turfgrass color or overall quality.
    • Air-layering as a Method of Asexual Propagation of Mesquite

      Hagen, R. H.; Palzkill, D. A.; Kopec, David M. (College of Agriculture, University of Arizona (Tucson, AZ), 1989)
      Three 12-year-old Prosopis chilensis were successfully layered in spring and late summer. The best rooting occurred with 1 cm stems treated with either 5,000 or 15,000 ppm IBA. Air-layers treated with IBA had a higher rooting rate and better root quality than untreated air-layers.
    • Alternatives for Tree Staking

      Schuch, Ursula K.; Kelly, Jack; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
      Staking is a common practice following planting of most trees in the landscape. The objectives of this project were to demonstrate four methods of staking trees and the effect on subsequent caliper growth and taper development. Master gardener volunteers were involved in this project. Four methods of staking were used on two different tree species. Acacia stenophylla were 3.1 m tall at planting and were difficult to keep upright with one or two tall stakes. All acacias staked with root stakes or short stakes required corrective pruning to establish a new leader. Prosopis velutina staked with root stakes or short stakes developed greatest taper within 6 months after transplanting. Root stakes will not require removal of staking materials.
    • Application of Proxy PGR for Poa Seed Head Suppression, 2000

      Kopec, David M.; Gilbert, Jeff J.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
      Proxy (ethephon) was applied to 100% pure stands of Poa annua as either a single or repeat application 24 days apart at both a five and ten-ounce product rate per 1000 square feet. Percent plot seed heads were decreased significantly on three of five evaluation dates before either the loss of treatment effect and/or environmental conditions triggered profuse flowering (by 20 April, 2000). The five-ounce rate produced moderate seed head suppression at 16 and 25 days after the first treatments by which afterwards, control was minimal. By April, the five-ounce repeat applications were no better in suppression of seed heads than either of the single applications, regardless of application timing (March 3 or 29). The ten-ounce rates generally produced 40% - 80% greater seed heads suppression than the five-ounce rate treatments. Maximum seed head control was achieved by the repeat applications (March 3 and 29) of the ten-ounce rate, which consistently produced between 8% and 19%, seed head cover up until the first ten days of April 2000. Proxy, when applied at the five-ounce/M rate had the greatest effect in seed head suppression early in the test (10 March). Perhaps earlier season applications at the five-ounce rate may be necessary to manifest greater suppression initially, and perhaps in a cumulative fashion for season long control.
    • Aquatrols Surfactant Study on Turfgrass Nutrient Uptake

      Walworth, James; Kopec, David M.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
    • Assessing the Potential Use of TENACITY (mesotrione) Herbicide For use as a Control Agent for Poa annua In Conjunction With Fall Overseeding of Bermudagrass

      Kopec, David M.; Gilbert, Jeff J.; Nolan, Steve; Pessarakli, Mohammed; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2009-02)
      Tenacity herbicide (mesotrione) was evaluated for use as both a pre-emergent and post- emergent herbicide in conjunction with fall overseeding of bermudagrass with perennial ryegrass. Tenacity herbicide, when applied @7 DBOS, 1 DBOS, at first mowing (2 WAOS) or 3 weeks after the first mowing (5 WAOS) did not cause a reduction in stand of perennial ryegrass compared to non-treated controls. There was essentially no difference in ryegrass emergence and cover for Tenacity when applied at the 2.0 oz. versus the 3.0 oz AI/A rate. When applied at these rates at both 7 DBOS and at the first mowing, treatments 1, 3, and 6 produced similar results. Overseeding occurred on October 16, 2007. Intense Poa annua pressure dominated the overseed ryegrass by late December, causing a decline in existing ryegrass cover. Only the latter applied treatments (of Prograss, or tank mixes which contained Prograss with Tenacity) regained sizable amounts of ryegrass by the end of February and early March. Percent weed control was ineffective for treatments which did not include Prograss herbicide. The split application of Prograss of 0.75 lbs AI/a applied @ 8 WAOS and again @ 12 WAOS resulted in the greatest amount of Poa annua control, and the greatest amount of ryegrass. Tenacity (mesotrione), when applied at rates and timings observed here, was safe for perennial ryegrass emergence, but ineffective on Poa annua pre-emergence and as a post emergent agent based on the subsequent growth of Poa annua.
    • Assessment of Application Rate and Formulation of Imazaquin Herbicide on Purple Nutsedge Suppression

      Kopec, D. M.; Heathman, E. S.; Mancino, C. F.; Moharram, H. N.; Kopec, David M. (College of Agriculture, University of Arizona (Tucson, AZ), 1989)
      A field test was implemented at Paradise Valley Country Club to investigate the effect of two rates of imazaquin (Image) herbicide (0.38 and 0.50 lbs ai /a) in both the granular (G) and emulsifiable concentrate formulation on purple nutsedge and common bermudagrass in a mixed stand (85 ± 20% nutsedge).
    • Best Management Practices for Sea Isle 2000 Surface Conditions as a Putting Green Turf Under Desert Conditions

      Kopec, David M.; Gilbert, Jeff J.; Walworth, James; Pessarakli, Mohammed; Kerr, D.; Spence, J.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
      Sea Isle 2000, the recently developed Seashore paspalum cultivar intended for use on golf greens, was subjected to various surface cultivation practices of grooming, vertical mowing, and topdressing frequency, in order to investigate the (1) effects of these cultural practices on turfgrass quality (2) effects on ball roll distance (BRD), so as to devise best management practices (BMP) for cultural management recommendations for this grass in a hot/dry climate. The trial was conducted for the two summer seasons of 2002 (year1), and 2003 (year 2). Turfgrass quality in year 1 was significantly affected by imposed management treatments on all four evaluation dates, in which the groom vs. non-groom contrast was highly significant. Nongroomed treatments produced better quality than turf groomed 5-6x weekly. In year two, the cultural management treatment effect was not significant, and treatment means ranged from 5.5 to 7.8. The nongroomed/ topdressed and verticut at 14-day treatment had mean quality scores of 7.0 or greater on three of four evaluations in year two. This treatment had the least number of cultural management contact events. The most aggressive treatment in terms of the number of contact events (groom/topdressed and vertically mowed at 7 days) never reached a mean quality score of 7.0, but had acceptable turf otherwise (6.8, 6.5, 5.8 and 6.5 in year two). The treatments that did not receive any vertical mowing (groom/topdressed and verticut at 7 days and groomed/topdressed and verticut at 14 days) always produced mean turf quality scores of 6.0 or above. Over the two year test, the nongroomed treatments which were both verticut and topdressed at 7 or 14 day intervals had 12 of 16 possible quality mean scores of 7.0 or more. The turfs which were groomed and topdressed only at 7 or 14 day intervals (never verticut) had mean quality scores of 7.0 or more on 6 of 16 possible rating scores. Turfs that were groomed/topdressed and verticut at either 7 or 14`day intervals had mean quality scores of 7.0 or greater on 4 of 16 possible evaluation scores. For Ball roll distance (BRD) in year one, the treatment F ratio was significant on five of the ten BRD measurement events, with significance occurring on double mowed turfs on three events, and twice when plots received supplemental rolling. Rolling with an 875 lb Brouer roller numerically increased BRD values on all treatments (over double mowing alone) on 5 July, 16 August, and 26 August, decreased BRD values on 19 July, and had no effect for BRD on 26 July. The greatest BRD values which occurred during year one, was a test mean of 103 inches (double mow only) and 98" for rolled turfs. In year two, the treatment F ratio for treatment effects was not statistically significant on any evaluation date. This was true when BRD was taken after turfs were double mowed, and also followed by rolling. Rolling had minimal benefit, and was inconsistent in BRD effect. BRD was almost 20% greater in year two than a in year one. When BRD was recorded only after double mowing, turfs that were not groomed ranked numerically higher than groomed turfs for BRD response on all data sampling dates in year one. In general, turfs which received the most frequent number of cultural management practices (regular grooming, topdressing and vertical mowing ) tended to have the lowest ranking BRD values, except towards the seasons end (16 and 26 August). Although the main "treatment" effect in the ANOVA was significant on 3 of 5 collection dates (for double mowed BRD values), these trends show that in general, regular grooming decreased BRD values more so than for non-groomed surfaces. In year two, BRD values were essentially identical in mean performance, ranging only a few inches in BRD when measured after the standard double mowing. The greatest difference in BRD among treatments occurred on 27 June, as a BRD of 99.8" occurred for turfs that were non-groomed/topdressed and vertically mowed every 7 days versus non-groomed/topdressed and vertically mowed every 14 days (105"). Again note that there were no significant treatment effects for BRD in year two. When BRD was measured after mowing, followed by additional rolling , the rolling effect tended to increase BRD values across all treatments in year one, except in July, which normally had the most humid weather. Rolling did increase BRD values by 10% in early July (July 5), but also decreased, or had no effect on BRD in the middle or late July (16 and 26 July), and then increased BRD values slightly in August (16, 26 August) of year one. Although the largest increase in BRD values from rolling occurred in early July (almost 9 inches) of year one, the effect was not significant between surface treatments. Rolling was significant when imparted across surface management treatments in August of year 1, as at least one of the two non-groomed turfs tended to have the largest BRD values after rolling. In year two, supplemental rolling imparted very little gain in BRD, except in late September. Substantial increases or decreases in BRD did not occur from rolling relative to treatments in year two, as sometimes occurred in year one. BRD averages across all treatments (with the addition of rolling) were from 96.4" - 109.8" in year two. For both years, rolling) was inconsistent with respect to BRD. Rolling on the day of BRD assessment only sometimes increased, decreased, or had no effect on BRD. Rolling as a regular cultural management treatment should be evaluated. BMPS for Quality and BRD Performance together: In year one, the "groom" treatment which was verticut and topdressed every 7 days always ranked the slowest for BRD responses. While this specific treatment always ranked lowest in BRD, it did not have the lowest overall turf quality scores. Groomed turfs which were verticut and topdressed every 14 days ranked the lowest for quality scores on three of four evaluation dates. Therefore in year one, treatments which produced (in general terms) the greatest BRD values and ranked the highest in overall quality were turfs which received no-grooming, and topdressed either every 14 or 7 days. The treatment which produced the lowest ranking BRD values and lowest ranking quality scores in year one, was the treatment of grooming, verticutting and topdressing every 14 days. In year two, BRD was not related to any surface cultivation treatment. Although not statistically significant, nongroomed plots topdressed either at 7 or 14 day intervals, ranked first for BRD in late season (3 September, 30 September). BRD values were in general, 10-20% greater across all treatments in 2003 than in 2002. Although BRD and quality were not significant in year two, certain trends resulted over the two year test period in that plots that were not groomed had mean treatment quality scores of 7.0 or more on 12 of 16 possible (joint treatment) evaluations. These treatments also had high BRD values. Also, treatments devoid of vertical mowing (groomed/topdressed only at either 7 or 14 day intervals) produced mean quality scores of 7.0 or more on 6 of 16 possible (joint treatment) events over the two year period. BRD values for these treatments were always within 1-2 inches of the test mean BRD values as well. Treatments which received the most frequent contact events (regular grooming/topdress/verticut at either 7 or 14 day intervals over two years, had mean quality scores of 7.0 or greater on only 16 possible events. Over the course of the study, in general, turfs which were non-groomed / verticut and topdressed @ either 7 or 14 day intervals produced the higher ranking quality turfs, along with higher ranking BRD performance. Long term BRD values would most likely include a mixture of topdressing and verticutting either at 7 or 14 days internals, with grooming practiced on an as needed basis, especially during the first two thirds of the summer season.
    • Branch Induction with Cytokinin to Improve Appearance and Increase Cutting Production of Jojoba

      Ravetta, D.; Palzkill, D. A.; Kopec, David M. (College of Agriculture, University of Arizona (Tucson, AZ), 1988)
      Treatment of jojoba plants with foliar sprays of benzyladenine (BA) alone, or in combination with gibberellin(4+7) (GA(4+7)) fatly increased branching frequency compared to untreated control plants and to plants from which all shoot tips were removed (pinched). Use of BA by itself resulted in an adverse reduction in intemode elongation. This was overcome in treatments which included GA(4+7) Use of GA(4+7) by itself resulted in reduced branching and abnormal shoot elongation. Pruning (pinching) of all shoot tips resulted in a slight increase in branching over untreated plants, but it had much less effect on branching than did treatments with BA. Results were very similar on two different clones tested.
    • Can Applied ABA be Used in Desert Turfgrass Management?

      Kopec, David M.; Suarez, Armando; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
    • Characterization of Amino Acids and Carbohydrates Found in Whitefly Honeydew As the First Step Toward Bioloical Control

      Byrne, D. N.; Miller, W. B.; Stanghellini, M. E.; Kopec, David M. (College of Agriculture, University of Arizona (Tucson, AZ), 1989)
      A Florida strain of sweet potato whitefly, Bemisia tabaci (Gennadius), was found to have an expanded range which includes several new food crops. To determine why, we examined how it processes plant nutrients. The amino acid and carbohydrate content of phloem sap of poinsettia and pumpkin and of honeydew produced by the Florida strain and a strain from Arizona feeding on both plants were analyzed. Poinsettia phloem sap contained 15 amino acids; 14 of these were in pumpkin phloem sap. Almost all the same amino acids were in the honeydews produced by the two strains on the two hosts. Approximately half of the amino acids found in the honeydew were at concentrations which were significantly lower than concentrations in the phloem sap. Honeydew from both hosts contain six additional amino acids. The major one was glutamine which may be used to expel nitrogen. Carbohydrates in phloem sap and honeydew were common transport sugars, like sucrose. Both honeydews contained trehalulose, a disaccharide not previously associated with insects. Both strains processed phloem sap and honeydew from both plants in the same manner, but the Florida strain produced significantly larger quantities of honeydew; it is therefore assumed to process more phloem sap. Since this strain has access to more phloem sap it also has access to more of the amino acids which are in short supply in the phloem sap of some plants allowing it to broaden its range.
    • Chemical Growth Retardant Effects on Easter Lilies

      Bailey, D. A.; Miller, W. B.; Kopec, David M. (College of Agriculture, University of Arizona (Tucson, AZ), 1988)
      Plants of Lilium longiflontm Thunb. 'Nellie White' recei,yed the following treatments during forcing: 1) control; 2-3) gne or two sprays of 50 mg-liter ancymidol 4-9) one or two sprays of 5, la, or 15 mg-liter XE-1019; or 10) one spray of 20 mg-liter XE-1019. All growth retardant treatments reduced plant height compared to controls. Plant height decreased linearly with increasing concentration of XE-1019 for both one- and two-spray treatments. High concentrations of XE-1019 delayed anthesis; ancymidol treatments did not. Individual corolla length was not affected by treatments. Treatments did not affect daughter bulb depletion or new daughter bulb growth. Total leaf area and leaf dry weight decreased as XE-1019 concentration increased; ancymidol treatments did not affect leaf area, but did reduce leaf dry weight. Leaf total soluble carbohydrate decreased with increasing concentration of XE-1019.
    • Chemical Height Control of Florists' Hydrangeas

      Bailey, D. A.; Kopec, David M. (College of Agriculture, University of Arizona (Tucson, AZ), 1988)
      XE-1019 (2 foliar sprays of 10, 2Q or 30 mg-liter⁻¹) was applied to plants of Hydrangea macrophylla Ser. 'Rose Supreme' during greenhouse forcing. Doses applied resulted in excessive reductions in shoot elongation and inflorescence diameters and delayed anthesis. Shoot growth was reduced with increasing XE-1019 concentration. Shoot length was reduced 46 %; stem dry weight was reduced 31 %; leaf area per shoot was reduced 44 %; inflorescence height was cut by 45 %; and inflorescence mass was reduced 48% with the 30 mg-liter⁻¹ XE-1019 treatment. Specific leaf weight increased with increased XE -1019 concentration (192% increase with the 30 mg-liter⁻¹ treatment) resulting in thicker leaves at anthesis. XE-1019 is an effective height control agent for florists' hydrangeas, and shows significant activity at very low (less than 0.2 mg a.i. per plant) doses.
    • Comparing Growth Responses of Selected Cool-Season Turfgrasses under Salinity and Drought Stresses

      Pessarakli, Mohammed; Kopec, David M.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2009-02)
      This study was conducted in a greenhouse, using hydroponics system, to compare growth responses of three cool-season turfgrass species, Creeping bentgrass (Agrostis stolonifera), Rough bluegrass (Poa trivialis), and Perennial ryegrass (Lolium sperenne) in terms of shoot and root lengths and dry matter (DM), and percent canopy green cover (%CGC) under salinity and drought stresses. Grasses were grown in Hoagland solution for 90 days prior to initiation of salinity or drought stresses. Then, 24 meq NaCl/L culture solution/day were added for each -0.1 MPa OP of salinity stress, or 75 and 119 g of PEG/L were added for -0.2 and -0.4 MPa OP of drought stress treatments, respectively. The treatments included control, -0.2 and -0.4 MPa OP salinity, -0.2 and -0.4 MPa OP drought stress. Four replications of each treatment were used in a RCB design experiment. During the stress period, grass shoots were clipped weekly for DM production, shoot and root lengths were measured, and %CGC was evaluated. The weekly clippings and the roots at the last harvest were oven dried at 60° C and DM weights were recorded. All 3 grass species were more severely affected by drought than salinity. Bluegrass was the most and bentgrass the least severely affected by either drought or salinity stress.