Progress 10/01/97 to 09/30/03
Outputs
During the life of this project turfgrass weed management systems were developed. Three sequential applications of the herbicide quinclorac (0.56 kg/ha) at 21 day intervals or a mixture of quinclorac at 0.8 kg/ha plus diclofop at 0.75 kg/ha applied twice provided 85 to 90% torpedograss (Panicum repens) control. Mowing just prior to quinclorac application did not reduce torpedograss control compared to a one week interval between mowing an application. In addition, level of nitrogen fertility had no impact on quinclorac activity. Trifloxysulfuron was evaluated for torpedograss, kyllinga and purple nutsedge (Cyperus rotundus) management in hybrid bermudagrass turf. Two sequential applications (0.022 kg/ha) of a sprayable formulation at 4 to 6 week intervals provided 80 to 90% control of all three species without causing injury to the turfgrass. Tropical signalgrass (Urachloa subquadripara), one of the most serious weed pests in Florida turfgrass, germinates best at pH 5
to 6, temperatures of 25 to 30 C and at water potentials >-0.04 Mpa. Tropical signalgrass shoots emerged from as deep as 6 cm with maximum emergence from seed placed on the soil surface. Tropical signalgrass emerged during mid-March in the field in central Florida when soil and ambient temperatures were 20 C. Postemergence herbicide treatments that are registered for use in St. Augustinegrass were ineffective for control of tropical signalgrass. Several Preemergence treatments, however, provided excellent control. These included prodiamine, dithiopyr, oryzalin, benefin + oryzalin or benefin + trifluralin. Tolerance of seashore paspalum (Paspalum vaginatum), a turfgrass species that tolerates high salt content in irrigation water, to standard turfgrass herbicides was detrmined. Seashore paspalum was not injured by preemergence applications of several dinitroaniline herbicides including prodiamine, pendimethalin and trifluralin. Postemergence treatments of quinclorac, metsulfuron,
clopyralid, bentazon, halosulfuron, imazaquin, bromoxynil and metribuzin were also tolerated by seashore paspalum. Ethofumesate, asulam, sethoxydim, MSMA, imazapic and clethodim caused damage to the seashore paspalum. Experiments were conducted under greenhouse condition to evaluate the salt tolerance of eight weed species: torpedograss, dollarweed, Virginia buttonweed, large crabgrass, common bermudagrass, purple nutsedge, goosegrass, and Florida pusley to determine the potential for using saltwater for weed management in seashore paspalum. The weeds were subjected to five seawater concentrations: 34,000 ppm salt (1x), 25,500 ppm (3/4x), 17,000 ppm (1/2x), 8,500 ppm (1/4x), and untreated (0x). Crabgrass, common bermudagrass, and purple nutsedge were controlled 70% or greater by 1/2x or greater saltwater while dollarweed, Virginia buttonweed, goosegrass, and Florida pusley showed 70% injury at concentrations of 1/4x or greater. Torpedograss was not affected by any of the saltwater
treatments.
Impacts
Quinclorac offers effective control of torpedograss when used in a series of sequential applications. Mowing and fertility level appear to have little impact on quinclorac activity. Trifloxysulfuron controls both torpedograss and purple nutsedge, two serious perennial weed problems in turfgrass. Information developed on tropical signalgrass germination and emergence can be used by sod producers to select proper timing of preemergence herbicide applications. Depth of emergence information suggests that deep turning of the soil will bury tropical signalgrass deeper than the 6 cm maximum depth of emergence, thus providing a potential management tool for this weed. For areas where seashore paspalum is grown, the use of saltwater for irrigation will also provide significant weed control and could reduce herbicide use on this turfgrass species by 25 to 50%.
Publications
- Teuton, T. C., J. B. Unruh, B. J. Brecke, G. E. MacDonald, G. L. Miller and J. T. Ducar. 2003. Control of tropical signalgrass in a St. Augustinegrass sod production system. Weed Technol. (In Press)
- Teuton, T. C., B. J. Brecke, J. B. Unruh, G. E. MacDonald, G. L. Miller and J. T. Ducar. 2004. Factors affecting seed germination and seedling emergence of tropical signalgrass. Weed Sci. (In Press)
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Progress 10/01/01 to 10/01/02
Outputs
Tropical signalgrass (Urachloa subquadripara), one of the most serious weed pests in Florida turfgrass, germinates best at pH 5 to 6, temperatures of 25 to 30 C and at water potentials >-0.04 Mpa. Tropical signalgrass shoots emerged from as deep as 6 cm with maximum emergence from seed placed on the soil surface. Tropical signalgrass emerged during mid-March in the field in central Florida when soil and ambient temperatures were 20 C. Postemergence herbicide treatments that are registered for use in St. Augustinegrass were ineffective for control of tropical signalgrass. Several Preemergence treatments, however, provided excellent control. These included prodiamine, dithiopyr, oryzalin, benefin + oryzalin or benefin + trifluralin. Trifloxysulfuron was evaluated for torpedograss (Panicum repens) cocks-comb kyllinga (kyllinga squamulata) and purple nutsedge (Cyperus rotundus) management in hybrid bermudagrass turf. Two sequential applications (0.022 kg/ha) at 4 to 6
week intervals provided 80 to 90% control of purple nutsedge and cocks-comb kyllinga and 60 to 70% control of torpedograss without causing injury to the turfgrass. Tolerance of seashore paspalum, a turfgrass species that tolerates high salt content in irrigation water, to standard turfgrass herbicides. Seashore paspalum was not injured by preemergence applications of several dinitroaniline herbicides including prodiamine, pendimethalin and trifluralin. Postemergence treatments of quinclorac, metsulfuron, clopyralid, bentazon, halosulfuron, imazaquin, bromoxynil and metribuzin were also tolerated by seashore paspalum. Ethofumesate, asulam, sethoxydim, fluazifop, MSMA, imazapic and clethodim caused damage to the seashore paspalum.
Impacts
Information developed on tropical signalgrass germination and emergence can be used by sod producers to select proper timing of preemergence herbicide applications. Depth of emergence information suggests that deep turning of the soil will bury tropical signalgrass deeper than the 6 cm maximum depth of emergence, thus providing a potential management tool for this weed. Torpedograss and purple nutsedge are serious weed problems in hybrid bermudagrass. Trifloxysulfuron offers effective control of these pests when used in a sequential application
Publications
- Lawson, R. N., J. B. Unruh and B. J. Brecke. 2002. Lawn burweed (Soliva pterosperma) control in hybrid bermudagrass (Cynodon dactylon x C. transvaalensis) and common centipedegrass (Eremochloa ophiuroides). Weed Technol. 16:84-87.
- Unruh, J.B., B.J. Brecke, J.L. Dusky and J.S. Godbehere. 2002. Fumigant alternatives for methyl bromide prior to turfgrass establishment. Weed Technol. 16:379-387.
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Progress 10/01/00 to 10/01/01
Outputs
Trifloxysulfuron was evaluated for torpedograss (Panicum repens) kyllinga and purple nutsedge (Cyperus rotundus) management in hybrid bermudagrass turf. Two sequential applications (0.022 kg/ha) of a sprayable formulation at 4 to 6 week intervals provided 80 to 90% control of all three species without causing injury to the turfgrass. Tolerance of seashore paspalum, a turfgrass species that tolerates high salt content in irrigation water, to standard turfgrass herbicides. Seashore paspalum was not injured by preemergence applications of several dinitroaniline herbicides including prodiamine, pendimethalin and trifluralin. Postemergence treatments of quinclorac, metsulfuron, clopyralid, bentazon, halosulfuron, imazaquin, bromoxynil and metribuzin were also tolerated by seashore paspalum. Ethofumesate, asulam, sethoxydim, MSMA, imazapic and clethodim caused damage to the seashore paspalum.
Impacts
Torpedograss and purple nutsedge are serious weed problems in hybrid bermudagrass. Trifloxysulfuron offers effective control of these pests when used in a sequential application.
Publications
- Brecke, B. J., J. B. Unruh, and J. A. Dusky. 2001. Torpedograss (Panicum repens) control with quinclorac in bermudagrass (Cynodon dactylon X C. transvaalensis) turf. Weed Technol. (In Press).
- Unruh, J.B., B.J. Brecke, J.L. Dusky and J.S. Godbehere. 2002. Fumigant alternatives for methyl bromide prior to turfgrass establishment. Weed Technol. (In Press).
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Progress 10/01/99 to 09/30/00
Outputs
Quinclorac was evaluated for torpedograss (Panicum repens) management in hybrid bermudagrass turf. Three sequential applications (0.56 kg/ha) of a sprayable formulation at 21 day intervals or a mixture of quinclorac at 0.8 kg/ha plus diclofop at 0.75 kg/ha applied twice provided 85 to 90% control. A granular formulation (quinclorac impregnated fertilizer) applied three times (0.56 kg/ha each) at 21 day intervals provided 90 to 95% control suggesting that a significant portion of the applied quinclorac is absorbed through the roots and rhizomes of the torpedograss. Mowing just prior to quinclorac application did not reduce torpedograss control compared to a one week interval between mowing an application. In addition, level of nitrogen fertility had no impact on quinclorac activity. CGA 362622, a new herbicide being evaluated in warm-season turfgrass, provided 85% control of torpedograss and 85 to 90% purple nutsedge control with minimal damage to hybrid
bermudagrass.
Impacts
Torpedograss is a serious weed problem in hybrid bermudagrass. Quinclorac offers effective control of this pest when used in a series of sequential applications. Mowing and fertility level appear to have little impact on quinclorac activity. CGA 362622 may offer control of both torpedograss and purple nutsedge, two serious perennial weed problems in turfgrass.
Publications
- Brecke, B. J. and J. B. Unruh. 2000. CGA 362622 for torpedograss (Panicum repens) and purple nutsedge (Cyperus rotundus) control in bermudagrass. Proc. South Weed Sci. Soc. 53.
- Edenfield, M. W., B. J. Brecke, and J. B. Unruh. 2000. Torpedograss control in bermudagrass (Cynodon dactylon) with quinclorac. Proc. South Weed Sci. Soc. 53.
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Progress 10/01/98 to 09/30/99
Outputs
Quinclorac was evaluated for torpedograss (Panicum repens) management in hybrid bermudagrass turf. Three sequential applications (0.56 kg/ha) of a sprayable formulation at 21 day intervals or a mixture of quinclorac at 0.8 kg/ha plus diclofop at 0.75 kg/ha applied twice provided 80 to 85% control. A granular formulation (quinclorac impregnated fertilizer) applied three times (0.56 kg/ha each) at 21 day intervals provided 90 to 95% control suggesting that a significant portion of the applied quinclorac is absorbed through the roots and rhizomes of the torpedograss. Mowing just prior to quinclorac application did not reduce torpedograss control compared to a one week interval between mowing an application. In addition, level of nitrogen fertility had no impact on quinclorac activity.
Impacts
Torpedograss is a serious weed problem in hybrid bermudagrass. Quinclorac offers effective control of this pest when used in a series of sequential applications. Mowing and fertility level appear to have little impact on quinclorac activity.
Publications
- Brecke, B. J. and J. B. Unruh. 1999. Torpedograss and large crabgrass control in bermudagrass with quinclorac. Proc. Weed Sci. Soc. Am. 39:89.
- Edenfield, M. W., B. J. Brecke, and J. B. Unruh. 1999. The influence of turfgrass herbicides on purple nutsedge (Cyperus rotundus) dynamics. Proc. South Weed Sci. Soc. 52:249.
- Unruh, J. B., B. J. Brecke, and J. A Dusky. 1999. Fumigant alternatives for the potential replacement of methyl bromide in turfgrass situations. Agron. Abst. 91:124.
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Progress 10/01/97 to 09/30/98
Outputs
Quinclorac was evaluated for torpedograss (Panicum repens) management in bermudagrass turf. Three sequential applications of 0.56 kg/ha at 21 day intervals or a mixture of quinclorac at 0.8 kg/ha plus diclofop at 0.75 kg/ha applied twice provided 85 to 90% season-long control of torpedograss. Diclofop alone, asulam or MSMA provided less than 70% control. In another study sulfentrazone, halosulfuron, imazaquin and MSMA were evaluated for purple nutsedge (Cyperus rotundus) control. All treatments provided 80% or better control of nutsedge foliage. Soil was excavated and nutsedge tuber separated to determine the impact of treatment on nutsedge tuber production. While all treatment reduced purple nutsedge tuber production, only sulfentrazone lowered tuber numbers by more than 70%.
Impacts
(N/A)
Publications
- Brecke, B. J. 1998. Control of purple nutsedge in warm-season turfgrasses. Proc. South. Weed Sci. Soc. 51:86.
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