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- Author or Editor: K. J. Scott x
Siduron and quinclorac provide limited broadleaf weed control during seeded establishment of tall fescue. Carfentrazone and bromoxynil are contact herbicides that act primarily on broadleaf, dicot species. Research was conducted to evaluate tall fescue tolerance to carfentrazone or bromoxynil when integrated into traditional siduron and quinclorac weed control programs. Quinclorac at 0.84 kg·ha–1 applied at seeding followed by quinclorac at 0.84 kg·ha–1 35 days after emergence (DAE) and quinclorac at 1.68 kg·ha–1 plus carfentrazone at 0.034 kg·ha–1 applied DAE were the most injurious to tall fescue 42 and 49 DAE. While quinclorac sequential applications reduced turfgrass groundcover 42 DAE, tall fescue recovered by 49 DAE. Injury from all quinclorac treatments persisted until 63 DAE. Bromoxynil (0.28 or 0.56 kg·ha–1) or carfentrazone (0.017 or 0.034 kg·ha–1) caused minimal injury and no decrease in turfgrass groundcover when applied 35 DAE. While siduron applied at seeding followed by (fb) bromoxynil applied 35 DAE (6.7 fb 0.56 kg·ha–1) caused minimal tall fescue injury, a decrease in groundcover was observed at 49 DAE. No tall fescue cover reduction was observed for any treatment by 63 DAE. These data indicate that bromoxynil and carfentrazone can be safely used during seeded establishment of tall fescue beginning 35 DAE with no long-term effects on turfgrass stand development.
Research was conducted to evaluate the tolerance of tall fescue to mesotrione applied during establishment from seed. Nine field studies were conducted over a 3-year period (2004–2006) near Knoxville, Tenn., to evaluate the tolerance of seedling tall fescue [Schedonorus phoenix (Scop.) Holub] to mesotrione and quinclorac. The first evaluated tall fescue tolerance to single and sequential applications of mesotrione compared with quinclorac (multiple application study). The second evaluated the timing of mesotrione application on tall fescue injury and establishment (timing study). In the multiple application study, all treatments injured tall fescue 23% or less. Quinclorac reduced tall fescue groundcover up to 17% 63 days after emergence (DAE). Mesotrione at 0.28 kg·ha−1 applied 28 and 42 DAE or 14, 28, and 42 DAE decreased groundcover only 4% and 6% 63 DAE. In the timing study, mesotrione at 0.28 kg·ha−1 applied at 7 and 28 DAE injured tall fescue 17% to 21% 7 and 14 days after application; however, injury subsided to less than 10% by 28 days after application. Only mesotrione at 0.28 kg·ha−1 applied 7 DAE resulted in delayed tall fescue groundcover at 70 DAE. Variation was observed in Fall 2005 evaluations compared with other evaluations, which may be attributable to delayed seeding date and cool, wet conditions.
Visible injury in chilled avocados (Persea americana Mill.) was observed first in the distal end of fruit. The proximal end remained apparently unaffected unless exposure to chilling temperature was prolonged. In contrast, the concentration of endogenous Ca of individual fruit was always highest in the proximal end and lowest in the distal end. Severity of visible injury in stored fruit was significantly reduced when Ca was applied to harvested fruit by vacuum infiltration of CaCI2·
`Delicious' (Malus ×domestica Borkh.) apples were kept in sealed polyethylene bags (thickness 0.05 mm) and exposed to ethanol, propan-1-ol, butan-1-ol, and pentan-1-ol during storage at 0 °C. Rates of application varied from 1.85 to 120 mmol·kg-1. Complete control of superficial scald was achieved using 30 mmol·kg-1 of fruit with butan-1-ol or propan-1-ol; ethanol required 120 mmol·kg-1 to control the disorder, but at this concentration, purpling of the red skin occurred. Butan-1-ol and propan-1-ol did not affect the color. Pentan-1-ol caused severe skin injury resembling soft or deep scald of `Jonathan' apples. Apples were also kept in high purity N at 20 °C for up to 8 days before storage at 0 °C. Complete control of scald occurred with a 6- or 8-day exposure to N. Control of scald appears to be due to the accumulation of ethanol during exposure to N. Nitrogen treatments did not affect skin color.
Carfentrazone is a broadleaf weed control herbicide that is also used for control of silvery-thread moss (Bryum argenteum) in creeping bentgrass (Agrostis stolonifera) putting greens. Field studies were initiated in June 2006 and May 2007 to evaluate silvery-thread moss control with carfentrazone alone, carfentrazone applied with nitrogen (N) and/or topdressing (TD), N alone, TD alone, and mancozeb plus copper hydroxide. All treatments except for mancozeb plus copper hydroxide and the non-treated control reduced silvery-thread moss populations 16 weeks after initial treatment. Carfentrazone applied alone and carfentrazone followed by N decreased silvery-thread moss populations by 39%. Carfentrazone followed by TD and carfentrazone followed by N + TD decreased silvery-thread moss populations by 73% and 66%, respectively. These data indicate the importance of using cultural practices to control silvery-thread moss on creeping bentgrass putting greens.
For the control of soft scald of ‘Jonathan’ apples (Malus domestica Borkh.), a dip containing both diphenylamine and a vegetable oil was generally more effective and was considered to be more desirable than the use of either compound alone.
Respiration at 20°C of carrot roots (Daucus carota L.), potato tubers (Solanum tuberosum L.) and zucchini fruits (Cucurbita pepo L.) was reduced following exposure to either high levels of CO2 or low levels of O2 for a few days at 20°C. The reduced respiration rates were maintained for at least 2 weeks after treatment while the produce was ventilated with air.
CaCl2 dips reduced the incidence of storage breakdown in ‘Jonathan’, ‘Cox’s Orange Pippin’ and ‘Twenty Ounce’ apples. The use of CaCl2, benomyl and diphenylamine in a single dip further enhanced the effect of CaCl2 The uptake of water into fruit was increased by reducing the dip temperature from 20° to 5°C or by increasing the dip time from 0.5 to 30 minutes but CaCl2 dipping was no more effective in controlling breakdown at 5° than at 20°.