Browsing Turfgrass, Landscape and Urban IPM Research Report 1988 by Issue Date
Now showing items 1-20 of 27
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Estimating Turfgrass Water Use with AZMETThe Arizona Meteorological Network provides weather-based estimates of reference evapotranspiration (ETo) for much of southern, central and western Arizona. A simple 3-step procedure to convert ETo data into reliable estimates of turfgrass water use is described The procedure requires that AZMET ETo values be multiplied by a correction factor known as a crop coefficient (Kc). The selection of the Kc depends on the type and height of the turfgrass as well as desired turf quality. The procedure is well adapted for use on computers.
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Ryegrass Overseed Trials for 1986-1987Ryegrass cultivars, experimental accessions, blends and composite mixtures were tested for overall adaptation to overseeded turfgrass management practices under desert conditions. Entries were significantly different from each other for color and overall turfgrass quality. Gennplasm for overseeding differs for tolerance to close mowing under desert conditions. In most cases, the better adapted entries had superior scores in two years of testing.
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Localization of Reserve Remobilization During Scalet Formation on Lilium longiflorum ScalesWhen Lilium longiflorum bulb scales we removed and placed in a moist environment, new bulbs ("scalets") arise from the base of the original scale, providing a practical means of clonal propagation. To determine which region of the scale is responsible for the early development of the new scalet, investigations were conducted on the localization of stanch hydrolysis and accumulation of soluble sugars in basal distal and central regions. Over a six week period starch concentration decreases initially in the distal regions, followed by the central region. Soluble sugars increased in distal areas over this same time period These findings indicate the distal regions of a lily scale are important in the early development of the new scalet, in contrast to the adjacen4 basal region.
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Spray Carrier Volume and Irrigation Method Effects on XE-1019 Efficacy on PoinsettiasPlants of Euphorbia pulchenima Wind. 'Gutbier V-14 Glory Annette Hegg Dark Red', and 'Annette Hegg Brilliant Diamond' were treated with 37 iw a.i. of XE-1019 applied in 102, 204, or 408 ml-m⁻² foliar sprays. Half of the plants received overhead irrigation and the remaining received soil-surface irrigations. No spray carrier volume effect or irrigation effect was observed for final plant height, bract canopy diameter, or for days from start of short days to bloom. The results obtained do not support the hypothesis that spray carrier volume or irrigation method affect the efficacy of XE-1019 on poinsettias.
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Effect of Salinity Stress on Development of Pythium Blight of Agrostis palustrisSalinity stress predisposed cultivar Penncross creeping bentgrass to cottony blight caused by Pythium aphanidennatum at two temperature regimes. At 25-32 C, complete necrosis of all inoculated plants occurred at electrical conductivity (Ec) levels from 4.3-7.1 ds/m in 2 days, whereas at Ec levels of 0.5-2.8 ds/m death occurred within 3 days. At 25-27 C, complete necrosis of all inoculated plants occurred at Ec levels from 4.3-7.1 ds /m within a period of 5 days; no death was observed in control or inoculated plants at an Ec level of 0.5 ds/m. Increased salinity levels apparently affected the bentgrass rather than P. aphanidermatum. Mycelia' growth rate of the fungus was increased only slightly by salinity levels up to 7.1 ds/m. Zoospore production of P. aphanidermatum and two other species of Pythium decreased with increasing salinity levels up to 7.1 ds/m; production was completely inhibited at 14.2 ds/m.
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Use of Growth Retardants for Floral Initiation of HydrangeasFloral initiation was successfully stimulated for plants of Hydrangea macrophylla 'Rose Supreme' under non-inductive environmental conditions by spraying plants with XE-1019 or paclobutrazol. Effective treatments were 10 weekly of 5 biweekly sprays of 100 mg-liter ⁻¹ paclobutrazol; 5 biweekly sprays of 11 or 30 mg-liter⁻¹ XE-1019, and 4 triweekly (once every 3 weeks) sprays of 15 or 30 mg-liter⁻¹ XE-1019.
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Chemical Height Control of Florists' HydrangeasXE-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.
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Rooting of Stem Cuttings of Mortonia scabrellaMortonia scabrella can be successfully propagated by stem -tip cuttings during May to September. Better rooting seems to occur during the less stressful months of May and September than in mid-summer. A wide range of rooting response occurs between different clones; the best will root in the range of 70-80%, which should be acceptable in a commercial propagation situation. In one cycle of selection in which the best 3 out of 16 clones were selected for a repeat study, average rooting success increased from 6% to 33 %. Apparently genetic differences for rooting potential occur. Further selection from larger populations, and/or breeding for this trait should result in cutting propagation becoming relatively easy for this species.
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Effects of XE-1019 Spray Concentration of ChrysanthemumsPlants of Chrysanthemum moifolium Ramat. 'Ovaro' received 0, 10, 20, or 30 mg-liter ⁻¹ XE-1019 applied as a 204 ml-m⁻² foliar spray. Treatments did not affect time from start of short days to bloom or inflorescence height lunge. Inflorescence height and inflorescence display diameter both were reduced with increasing concentration of XE-1019.
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Determining Optimum Length of Bulb Cold Storage for Oriental Hybrid Lilies in ArizonaBulbs of three varieties of oriental hybrid lilies were stored at 4 °C for 6 to 12 weeks prior to greenhouse forcing at 18 °C night temperature. Increasing duration of storage reduced the number of days to shoot emergence, visible flower buck and anthesis for each variety. The number of days from planting to anthesis ranged from 70 to 102 and varied with cultivar and storage duration. Increasing durations of storage had no commercially significant effect on the number of flowers reaching anthesis, number of leaves or aborted flower buds. The varieties used in this study flower earlier than commercially established cultivars and may be successfully forced in Arizona for early spring holidays.
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Seed Germination Response of Penstemon spp. To Gibberellic AcidTreatment of seed with gibberellic acid (GA) resulted in significant increases in germination percent for Penstemon ambiguous, P. barbatus, P. eatoni, P. palmeri, P. parryi. P. pseudospectabilis, P. secundiflorus, and P. strictus in one or both of two experiments which were conducted. Germination of several other species increased with GA treatment, but differences were not significant.
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Podranea Height Control with XE-1019Foliar sprays of XE -1019 at 3, 4 9, 12, 15, l8 and 36 mg a.i. liter⁻¹ were found to be effective in controlling the height of Podroea ricasoliana However, at higher concentrations (greater than 12 ppm), undesirable leaflet curling and reductions in leaflet size were observed All treatments lost effectiveness in controlling internode elongation during week 4 and 5.
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Spray Carrier Volume Effects on XE-1019 and ChrysanthemumsPlant of Chysanthemum morífolium Rymat. 'Ovaio' received 0, 102, 204, 304 or 408 ml-m⁻² of 0, 40, 20, 13.3, and 10 mg-liter⁻¹ XE-1019, respectively. No treatment affected time from start of short days to bloom or inflorescence display diameter. All XE-1019 treatments resulted in shorter plants than controls did. No carrier volume effect on plant height was observed. The inflorescence height range per pot decreased with increasing carrier volume. The greater inflorescence height uniformity achieved with the high carrier volume is beneficial and warrants further investigation.
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Propogation and Nursery Production Studies With New Arid Land SpeciesSeveral species of low -water requiring species have been successfully propagated through vegetative and sexual means. Auxin treatments and bottom healing were beneficial in many cases. Development of improved propagation schemes, and subsequent growing practices, will increase grower success and profitability, eventually increasing availability of new low water use plants to the Arizona consumer. The long-term result of this work will be the availability of new, low-water use plant species which may be utilized by the homeowner and landscape contractor. The addition of new and exciting plant materials to the consumer market, it is hoped will accelerate the use of arid species in the Arizona landscape, resulting in water savings throughout the state, particularly in urban areas.