Eco, Milorganite, Ringer, and Sustane natural organic fertilizers, alone or combined with the synthetic organic fertilizer isobutylidene diurea (IBDU), were compared with IBDU alone for their effect on a `Tifdwarf' hybrid bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy] golf course putting green. Over the 2-year study period, no consistent differences were observed among the fertilizer treatments on the turfgrass growth parameters of quality, clipping weights, or root weights.
Abstract
Eight bermudagrass [Cynodon dactylon (L.) Pers. and related species] clonal selections were inoculated with a mixed sample of ectoparasitic nematodes and were grown for 5 months in 13-cm pots. Relative to control (noninoculated) pots, nematodes reduced root dry weight 13% (P < 0.01) but had no effect on overall shoot (clippings) yield. Commercially available cultivars ‘Tifgreen’ and ‘Tifdwarf’ had significantly greater root weight reductions and also supported significantly higher densities of the lance nematode, Hoplolaimus galeatus, than most other clones.
Abstract
Root growth of St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] and bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Davy] (C-4 plants), show distinct seasonal patterns different from those of the cool-season perennial grasses (C-3 plants). Root growth continued after winter shoot dormancy occurred, and at soil temperatures below 10°C. Severe browning of the entire root system was observed just after spring shoot greenup followed by a delay of about 3 weeks in new root initiation and replacement, even though significant shoot development was occurring prior to this period of root initiation.
Abstract
Three genetically diverse Kentucky bluegrasses (Poa pratensis L. cvs. Kenblue, Vantage, and Adelphi) and 6 other turfgrasses were evaluated for susceptibility to the greenbug, Schizaphis graminum Rondani. Nine common lawn weed species were also tested as potential alternative hosts. Heavy greenbug populations and feeding damage occurred on all 3 bluegrasses and on tall fescue (Festuca arundinacea Schreb. cv. Kentucky 31) and chewings fescue (Festuca rubra var. cummutata Guad. cv. Jamestown). Creeping bentgrass (Agrostis palustris Huds. cv. Penncross), bermudagrass (Cynodon dactylon L. cv. Midiron), perennial ryegrass (Lolium perenne L. cv. Derby), and zoysia grass (Zoysia japonica Steud. cv. Meyer) were not suitable hosts. No greenbugs survived on the 9 weed species tested.
Abstract
Postemergence applications of 1.1 and 0.6 kg/ha of sethoxydim (2-[l-ethoxyimino) butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-l-one) and fluazifop-butyl (butyl 2-[4-(5-trifluoromethyl-2-pyridyloxy)-phenoxy]propionate), respectively, resulted in 90% control of common bermudagrass (Cynodon dactylon) when applied directly over field-grown ornamentals. Comparable control was achieved by either single application or 2, half-rate, split applications. Of the 12 species tested, only ‘Hexe’ azalea was damaged by applications of fluazifop-butyl to a degree that the plants were unsaleable. All other species exhibited tolerance to both sethoxydim and fluazifop-butyl at the rates required to achieve grass control.
This study was conducted to determine rooting characteristics, root carbohydrate content, and performance of 10 bermudagrass [Cynodon dactylon (L.) Pers.] genotypes exposed to drought. A greenhouse study was conducted twice to determine root distribution and carbohydrate content throughout the soil profile during simulated drought stress. Root distribution among genotypes and accumulation of total nonstructural carbohydrate within roots differed with depths. Root mass at 30, 60, 90, and 150 cm was significantly correlated with turf quality during drought stress (r = 0.72, 0.86, 0.80, and 0.81, respectively) only for one of the two tests. Root carbohydrate distribution was not significantly correlated with turf quality for the selected bermudagrass genotypes.
Abstract
Electrolyte leakage and regrowth tests were used to estimate cold hardiness levels of field-grown ‘Midiron’ and ‘Tifgreen’ bermudagrass (Cynodon dactylon × C. transvaalensis crowns. The two procedures were in close agreement. ‘Midiron’ was hardier than ‘Tifgreen’ on all sampling dates. Greatest levels of freeze tolerance were –11°C for ‘Midiron’ and –7° for Tifgreen’ during December and January, ‘Midiron’ was killed at –5° in early June while ‘Tifgreen’ had lost all freeze tolerance by this date. Although the electrolyte leakage procedure was rapid and required no greenhouse space, it was relatively difficult to set up and evaluate.
Abstract
Methyl sulfanilylcarbamate (asulam) was effective for the selective control of several grassy weeds in established st. augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze), ‘Tifway’ bermudagrass (Cynodon dactylon L.), and ‘Emerald’ zoysiagrass (Zoysia matrella Merr.). Bahiagrass (Paspalum notatum Flugge) and centipedegrass (Eremochloa ophuroides (Munro) Hack.) were severely injured when asulam was used at a rate of 2.24 kg ai/ha. Thirty-six species of ornamental plants were relatively tolerant to foliage applications of asulam at rates of 2.24 and 4.48 kg ai/ha with growth normal on all but 4 ornamental species 22 weeks following treatment.
Two studies were conducted to determine if selected grass and dicot species had an allelopathic interaction with pecan (Carya illinoinensis Wangenh. C. Koch). Leachate from pots with established grasses or dicots was used to irrigate container-grown pecan trees. Leachates from bermudagrass [Cynodon dactylon (L.) Pers.], tall fescue (Festuca arundinacea Shreb. cv. Kentucky 31), redroot pigweed (Amaranthus retroflexus L.), and cutleaf evening primrose (Oenothera laciniata Hill) reduced leaf area and leaf dry weight about 20% compared to the controls. Bermudagrass, tall fescue, and primrose leachate decreased pecan root weight 17%, trunk weight 22%, and total tree dry weight 19% compared to the control. In a second study, trees were 10% shorter than the control when irrigated with bermudagrass or pigweed leachate.
One method of plant freeze protection involves the application of compounds that promote freeze avoidance or tolerance. FreezePruf, a commercially available product recently marketed to improve both freeze avoidance and tolerance, contains polyethylene glycol, potassium silicate, glycerol, silicone polyether surfactant, and a bicyclic oxazolidine antidessicant. The goal of the present study was to evaluate the protection level provided by FreezePruf using laboratory-based methods involving plants and plant parts from species capable and incapable of low-temperature acclimation. FreezePruf did not lower the freezing temperature of pepper (Capsicum annuum) seedlings, celosia (Celosia argentea) seedlings, detached tomato (Solanum lycopersicum) leaves, or postharvest tomato fruit. Spray application of the putative cryoprotectant did not increase the freeze tolerance of bermudagrass (Cynodon dactylon) crowns or stolons. It is possible that a greater level of protection could be achieved with other species or different experimental protocols.