• Spring Transition of Tifway (419) Bermudagrass as Influenced by Herbicide Treatments

      Kopec, David M.; Gilbert, Jeff J.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
      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 re-establishment 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.
    • Controlling Rhizoctonia Root Rot in Bedding Plants

      Mahato, Tilak; Olsen, Mary; Schuch, Ursula K.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
      Rhizoctonia root rot is caused by a soil borne fungus, Rhizoctonia solani and is a serious problem in bedding plants. The objective of this study was to determine the efficacy of three chemical and two biological products for controlling Rhizoctonia root rot in cool season and warm season bedding plants. Experiments were conducted with summer and winter bedding plants in a nursery production and landscape situation. The efficacy of conventional fungicides or biological products to control Rhizoctonia root rot in bedding plant production and simulated landscape growth cannot be evaluated from results of this study because of low mortality of plants.
    • 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.
    • Response of Cool Season Turfs when Overseeded on a Putting Green with a History of Rapid Blight Disease

      Kopec, David M.; Olsen, Mary W.; Gilbert, Jeff J.; Bigelow, Donna M.; Kohout, Michele; Twito, Mick; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
      Rapid blight disease is a potentially devastating disease on cool season overseed turfs when irrigated with saline water. A two year test was conducted on a closely mowed Tifgreen bermudagrass turf which was infected with visual symptoms of necrotic patches of turf, and various degrees of blighting. The test included a broad representation of turf species for overseeding in an effort to (1) determine selected specie/cultivar susceptibility and disease expression to rapid blight in the field and (2) survey and assess the association of laboratory isolate detection from field sampling, with disease occurrence and severity of expression of field maintained overseed turf. Over a two year period, Rapid blight, caused by Labyrinthula terrestris was capable of infesting most cool season grasses in this test. In year one, Dawson CRF, SRX 555 slender creeping red fescue, and SR 105210 slender creeping red fescue showed no positive lab detection results from field plots. In year two (2003-2004), only SRX 555 SLQ had only 1 plot known to carry Labyrinthula throughout the main infestation season. In year two, essentially all turf plots showed some symptomology of disease expression. This was confirmed by lab identification. Tiller infection rates varied from 2% to 80% infection in the lab from field samples. The relationship between tiller infection rates and field plot disease expression was determined by Pearson’s product and Spearman Rank correlation coefficients. Field plot disease scores were correlated with percent tiller infection rates, R² = -0.56 plot basis, and R² = –0.71 treatment mean basis, respectively. Spearman Rank correlation coefficients were R² =; -0.62 on a plot basis, and R² =–0.78 based on treatment means Agreement between the disease condition (yes/no) vs. lab findings (positive/negative) occurred on 51 of 59 plot cases, and was significant compared to chance alone occurrences. Over two years, entries which had low disease scores included Fult’s alkali grass, Dawson creeping red fescue, SRX 555 SLQ slender creeping red fescue, SR 5210 slender creeping red fescue, and Providence creeping bentgrass. Over two years, entries which produced high field disease rating scores included SR 3100 Hard fescue, TransEze intermediate ryegrass, SR 4400 perennial ryegrass, SR 7200 velvet bentgrass, SR 7100 colonial bentgrass, Sabre and Laser Poa trivialis, and Redtop.
    • 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)
    • Response of Nitrate and Ammonium on Growth of Prosopis Velutina and Simmondsia Chinensis Seedlings

      Hahne, Kathryn S.; Schuch, Ursula K.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
      The objective of this study was to determine whether mesquite (Prosopis velutina) and jojoba (Simmondsia chinensis) seedlings have a preference for the ammonia or nitrate form of nitrogen (N) to maximize growth and minimize N leaching when seedlings were grown in sand culture. Seedlings were fertigated with different ratios of NH₄⁺:NO₃⁻ to determine effects on shoot and root growth and N leaching. Nutrient solution containing 67 % NH₄⁺: 33 % NO₃⁻ resulted in greatest biomass of mesquite seedlings after 120 days of fertigation. N tissue concentrations of mesquite seedlings were highest for plants supplied with 100% ammonium. N leachate remained stable until 12 weeks after the onset of treatment, but increased significantly by week 16. Dry weight of jojoba seedlings did not differ throughout the experiment regardless of the nutrient solution provided, however N tissue concentration in jojoba seedlings fertigated with 100% ammonium was twice as high as that of plants fertigated with 100% nitrate.
    • Efficacy of Herbicides for Nutsedge Control in Turf

      Umeda, Kai; Towers, Gabriel; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
      The efficacy of six ALS herbicides for controlling purple nutsedge in bermudagrass turf was demonstrated in five field experiments during the summer of 2004. The highest degree of nutsedge control at 95% at the end of the summer was observed after three monthly applications of trifloxysulfuron at 0.026 lb a.i./A.. Three monthly applications of halosulfuron at 0.062 lb a.i./A controlled nutsedge 88 to 90% at the end of September to early October. Imazaquin at 0.5 lb a.i./A plus MSMA at 3.0 lb a.i./A gave 91% control of nutsedge with three applications. The most rapid and efficacious nutsedge control was observed with flazasulfuron giving 91% control at 15 days after a single application. The highest degree of nutsedge control with a single application of sulfosulfuron was 91 to 96% control at 28 days after treatment. In general, ALS herbicides applied as a single application or multiple applications provided one month of effective control following a first application. After one month, the degree of control declined unless repeated applications at monthly intervals or as needed were applied for extended control. Penoxsulam at 0.12 lb a.i./A in one test gave only 70% control. MSMA at 3.0 lb a.i./A was applied four times and nutsedge control at the end of the season was 63 to 66%.
    • Subterranean Termite (Isoptera: Rhinotermitidae) Mortality Due to Entomopathogenic Nematodes (Nematoda:Steinernematidae, Heterorhabditidae)

      Weeks, Brian; Baker, Paul; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
      Two species of entomopathogenic nematode were studied in terms of their survivability, detectability by the subterranean termite Heterotermes aureus, and their ability to induce mortality in H. aureus. Heterorhabdidtis bacteriophora (Poinar) and Steinernema carpocapsae (Weiser) are nematodes sold commercially as a means of biological control for termites. We used a laboratory method to determine how effective these nematode species might be under field conditions. Tests showed a difference in the survivability between nematode species and also ability to kill termites. It was also shown that H. aureus had no ability to detect either nematode species when given a choice between arenas infested with nematodes and not. Though nematodes might have some limited capacity for termite control, those considering using nematodes to control Heterotermes aureus may want to consider the species of nematode before making a purchase.
    • 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.
    • Evaluation of Fungicides for Control of Rapid Blight of Poa trivialis (2003)

      Olsen, Mary W.; Gilbert, Jeff J.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
      Rapid blight is a new disease of cool season turf grasses that has occurred on over a dozen golf courses in Arizona. It is now known to be caused by Labyrinthula terrestris, an organism in a group referred to as the marine slime molds. A trial was conducted in fall 2003 and winter 2004 to evaluate efficacy of selected fungicides for control of rapid blight at a golf course in central Arizona with a previous history of disease. Plots were established in late October2003 on a practice green on which Bermuda was overseeded with Poa trivialis. Treatments included Compass, Insignia, Fore, Bordeaux, Kocide 2000, Microthiol Disperss, Ecoguard and Floradox in various combinations and application dates. Disease symptoms appeared about 6 weeks after the first mowing and were evaluated in mid January. Results indicate that applications of Fore, Insignia and tank mixes of Insignia and Compass with Fore gave excellent control. Bordeaux, Compass alone, Compass alternated with Fore, Insignia alone, and Kocide gave good control. Microthiol Disperss, Floradox and Ecoguard gave poor control.
    • Investigations of the Host Range of Labyrinthula terrestris, a New Turfgrass Pathogen

      Bigelow, Donna M.; Olsen, Mary W.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
      Non-salt tolerant cultivars of rice, lettuce and radish as well as salt tolerant varieties of alfalfa, barley, and wheat were screened in the greenhouse and laboratory to determine if Labyrinthula terrestris, a new turfgrass pathogen, could infect plants other than turfgrasses. Wheat, barley and rice plants were infected, symptomatic and died. Radish and lettuce were infected but nonsymptomatic. Alfalfa was not infected and exhibited no symptoms. Results indicate that L. terrestris is capable of infecting and causing symptoms in plants other than cool season turfgrasses.
    • Growth of Legume Tree Species Growing in the Southwestern United States

      Schuch, Ursula K.; Norem, Margaret; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
      Vegetative shoot growth of eleven legume tree species growing under field conditions in the Southwestern United States in Arizona were monitored over two periods of twelve months. Species included plants native to the Southwestern United States, Mexico, South America, and Australia. Based on shoot extension and branch differentiation species could be grouped into three categories. Fast growing legumes included Acacia farnesiana, A. pendula, Olneya tesota, Parkinsonia floridum, and Prosopis chilensis. Intermediate growth rates were monitored for A. jennerae, A. salicina, and A. visco. Slow growing species in this study included A. stenophylla, P. microphylla, and P. praecox. No buds, flowers, or pods were observed for P. microphylla, O. tesota, and P. chilensis during the study. Of the remaining species those native to the Americas flowered in spring and those native to Australia flowered in fall or winter.
    • Observations of TADS Foramsulfuron Formulations on Sea Isle I Paspalum as Affected by Mowing Height and Foliar Applied Iron

      Kopec, David M.; Gilbert, Jeff J.; Kerr, D.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
    • Nitrogen Requirements of Prosopis Velutina during Early Seedling Growth

      Hahne, Kathryn S.; Schuch, Ursula K.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
      The objective of this study was to determine the optimum rate of N to maximize growth of Prosopis velutina seedlings and minimize N leaching when seedlings were grown in different substrates. Mesquite seedlings were grown in sand or soilless media and were fertigated with a solution of67 % NH₄⁺: 33 % NO₃⁻ at a rate of 25, 50, 100, or 200 mg N/L. After 60 days, plants in media produced 41 % more leaves and total biomass compared to those in sand. Leaf number was greatest for plants grown at 200 mg N/L in both substrates. Root biomass of plants in media showed no response to increasing N concentrations while root biomass of seedlings in sand were similar for the three lower N concentrations and nearly doubled for the highest one. Shoot biomass of seedlings receiving 25, 50, or 100 mg N/L was similar, but more than doubled for plants fertigated with 200 mg N/L. N leachate losses were highest from seedlings growing in sand and receiving the two higher N fertigations, those in media had greatest N leachate loss when fertigated at 200 mg N/L.
    • Evaluation and Comparison of Spotlight* Herbicide Combinations for Khakiweed Control in Turf

      Umeda, Kai; Towers, Gabriel; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
      The combination of Spotlight* at 1.0 pt/A plus Speedzone* at 4.0 pt/A gave 90% control of khakiweed at 14 days after treatment (DAT) and continued to offer acceptable control of 85% at 49 DAT. Acceptable control of 87 and 90% control was also observed at 14 DAT when Spotlight* was combined with Powerzone* or Speedzone*, respectively. The combinations of Spotlight* with Powerzone* or Trimec* were similar by marginally controlling khakiweed up to 21 DAT. Spotlight when combined with Turflon Ester* or Speedzone Southern* performed very similarly at all rating dates and did not offer acceptable khakiweed control.
    • Evaluation of Velocity* Herbicide for Poa annua Control in Turf

      Umeda, Kai; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
      Two or three applications of Velocity at 30 g ai/A controlled P. annua 63 to 82% in two field experiments. Multiple applications of Velocity at 17 day intervals provided a higher degree of P. annua control compared to applications made at 28 day intervals. At approximately one month after initial applications, Velocity treatments, single or sequential, demonstrated 50 to 77% control of P. annua. The activity on P. annua was minimal at two weeks after initial applications of 30 to 60 g ai/A and slight chlorosis was evident. Perennial ryegrass exhibited chlorosis at two weeks after applications and appeared to recover at one month.
    • Response and Nutrient Uptake in Bermudagrass Treated with Aquatrols Surfactant ACA 1848 in the Desert Southwest

      Walworth, James; Kopec, David M.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
      Aquatrols surfactant ACA 1848 was applied to Tifway 419 hybrid bermudagrass at rates of 12 or 48 ounces/acre and evaluated for turfgrass growth, performance, and nutrient uptake. Soil samples collected during the growing season were analyzed for inorganic nitrogen (ammonium and nitrate). Only on the last sampling date only (September 29), the soil nitrate-nitrogen level was slightly higher in the untreated control than in other plots. Otherwise, soil nitrogen levels did not differ among treatments. Growth measurements and visual ratings did not differ among treatments at any time during the growing season, indicating that surfactant treatments did not affect either of these parameters. Leaf clippings collected throughout the growing season were analyzed for total nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, sodium, boron, copper, iron, manganese, and zinc. With only one exception, differences in nutrient content among treatments were statistically non-significant at the 5% significance level. That exception occurred on August 18 when the turfgrass treated with surfactant at the 12 oz/a/wk level had less zinc than turfgrass in the 0 or 48 oz/a/wk treatments. There was a noticeable, but non-significant trend, observed as follows; the highest level of surfactant treatment (48 oz/a/wk) resulted in the highest tissue levels of phosphorus, potassium, sulfur, sodium, boron, and copper in samples collected on July 21 (day 203), August 4 (day 217), and September 1 (day 245). Calcium, magnesium, and iron levels were highest in this treatment on August 4, but these differences were extremely small and always statistically nonsignificant and this trend was not observed on other sampling dates. There were no consistent rate trend responses (i.e. where the higher level of surfactant treatment produced a greater response than the lower rate) throughout the test. On all sampling dates, the untreated control contained more manganese than either of the surfactant treatments; the differences were not statistically significant and were not rate related. In this field study, there were no turfgrass responses, either positive or negative, that we could attribute to Aquatrols ACC 1848 applied at 12 and 48 oz/a weekly. The magnitudes of response differences observed in this study were not large enough to identify statistically significant differences.
    • Comparison of Sulfonylurea Herbicides for Spring Transition

      Umeda, Kai; Towers, Gabriel; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
      In six field experiments that were conducted during the spring of 2004 with seven sulfonylurea herbicides for removing perennial ryegrass from bermudagrass turf, the most rapid response and effective ryegrass removal occurred with the latest applications made in June compared to applications made in April or May. Flazasulfuron, foramsulfuron, rimsulfuron, trifloxysulfuron, and chlorsulfuron were effective in removing most of the ryegrass. Sulfosulfuron and metsulfuron were least effective for removing ryegrass, especially during the cooler April and May timings.
    • School IPM

      Gouge, Dawn H.; Smith, Kirk A.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
    • Evaluation of Fungicides for Control of Rapid Blight of Poa trivialis (2002)

      Olsen, Mary W.; Bigelow, Donna M.; Kopec, David M. (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2004-02)
      Rapid blight is a new disease of cool season turf grasses that has occurred on several golf courses in Arizona over the past five years. It is now known to be caused by a Labyrinthula sp., an organism in a group referred to as the marine slime molds. A trial was conducted in fall 2002 to evaluate efficacy of selected fungicides for control of rapid blight at a golf course in central Arizona with a previous history of disease. Plots were established in October 2002 on a practice green on which Bermuda was overseeded with Poa trivialis. Treatments included Compass, Insignia, Fore, Eagle and Aqueduct in various combinations and application dates. Disease symptoms appeared several days after the first mowing and continued for over three months. Results indicate that both pre- and post-plant applications of Fore and post-plant applications of Insignia and Compass gave good control. The best results were obtained with the treatment of Fore combined with Compass that included a pre-plant application of Fore, or with post-plant application of Insignia.