Source: UNIVERSITY OF FLORIDA submitted to NRP
MANAGEMENT OF TROUBLESOME WEEDS IN PASTURES, RANGELAND, NATURAL AREAS, AND RIGHTS-OF-WAY.
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
0231798
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Oct 1, 2012
Project End Date
Sep 30, 2017
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
UNIVERSITY OF FLORIDA
G022 MCCARTY HALL
GAINESVILLE,FL 32611
Performing Department
Range Cattle Research and Education Center, Ona
Non Technical Summary
It has been estimated that the annual collective economic loss attributed to weeds in Florida pastures and rangeland is in excess of $180 million. These losses include a reduction in forage quality as well as cattle stress from plant toxicity or physical injury. Therefore, research is needed to develop management strategies that will allow producers to reduce these losses through increased forage production (i.e. higher animal stocking rates per unit area), increased forage quality, decreased incidence of animal toxicity and reduced physical injury from weeds. Forage quality. The main forages in Florida include bahiagrass, bermudagrass, stargrass, and limpograss. These forages are commonly used because they are relatively easy to produce and possess adequate forage quality (total digestible nutrient values of at least 50%). Conversely, common weedy species such as cogongrass, thistle, and dogfennel possess little or no forage value due to unpalatability or physical defense. By maintaining a weed-free grazing area, more quality forage can be propagated and animal productivity increases dramatically. Natural Areas Invasion of exotic species poses a serious threat to Florida's sensitive ecosystems. A reported 1,413 exotic plants species as naturalized in Florida, with 125 species listed as serious threats to natural areas. Of those, 65 are considered highly invasive because they are disruptive to native plant communities. Rights-of-way Each year the Florida Department of Transportation (FDOT) manages several thousand acres along state and federal highways. It is important to maintain healthy turf directly adjacent to the road surface in order to preserve the integrity of the driving surface. However, both native and invasive weeds colonize along the rights-of-ways. Weed competition weakens the turf and often leads to areas of bare soil after the weed completes its seasonal life-cycle. Such areas are now vulnerable to erosion that will in-turn lead to safety concerns and higher maintenance costs. The primary method of weed management in rights-of-ways is mowing. Mowing is not highly effective on certain weed species. Therefore, some areas are mowed as many as 16 times per year. Direct costs from multiple mowing treatments are unknown as no information is usually provided on a per acre basis. As such, the economic impact of weeds on highway safety and maintenance is currently unknown. However, by integrating herbicides as a weed management tool, it is possible to reduce mowing frequency for weed control and possibly increase highway safety.
Animal Health Component
(N/A)
Research Effort Categories
Basic
(N/A)
Applied
(N/A)
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1021610114010%
2130790114010%
2131610114050%
2131620114020%
2132420114010%
Knowledge Area
102 - Soil, Plant, Water, Nutrient Relationships; 213 - Weeds Affecting Plants;

Subject Of Investigation
1620 - Warm season perennial grasses; 1610 - Pasture; 0790 - Rangelands, other; 2420 - Noncrop plant research;

Field Of Science
1140 - Weed science;
Goals / Objectives
1. Examine the efficacy of new and existing herbicide molecules for weed species common to pastures, rangeland, natural areas, and rights-of-way; 2. Determine the tolerance of forage and native species to new and existing herbicides; 3. Develop management strategies for perennial grass weeds in improved forage systems; 4. Identify problematic weeds and control measures in rights-of-way.
Project Methods
General Procedures: Experiments will be initiated in areas naturally infested with weed species. Standard production practices will be followed. The test areas will be in pastures where a dense stand of weeds is present. Herbicides will be applied as sprays using small-plot application equipment calibrated to deliver 280 L/ha at approximately 275 kPa. Plot size will vary according to the species under investigation. Treatments will be replicated four times in a randomized complete block experimental design. Weed control and forage injury will be visually evaluated routinely during the growing season. New Herbicide Evaluation. New herbicides will be evaluated for weed control effectiveness and forage tolerance as they become available. Forage Tolerance. New forage cultivars developed by the Florida Agricultural Experiment Station need to be evaluated for tolerance to some of the most commonly used herbicides available for grazing lands. For those products that cause some injury, it will be necessary to document forage recovery. Data will be recorded using visual estimations against an untreated control, and/or by periodically harvesting biomass from meter-square quadrats at specified intervals after treatment. Experiments will be established to determine if several management techniques (integrated management) will aid in reducing perennial grass infestation in improved bahiagrass pastures. A factorial arrangement of lime (as required by soil testing), N-P-K fertility, and micronutrients will be utilized to examine the impact of these inputs on bahiagrass and perennial weedy grass growth. The experiment will continue for at least five years, with annual fertilizer applications and lime as needed. Perennial grass weed control will be evaluated by visual cover and by counting GPS-located points within each experimental unit. Two to three field research sites will be established in each Florida Department of Transportation (FDOT) district to inventory the species vegetation present along rights-of-way. Coordination with district directors and/or team leaders within each district at location(s) where turf scores have been consistently low for turf quality. At each location species inventory will be recorded and soil samples will be taken from each location to measure soil pH to determine if the appropriate desirable vegetation can be successfully established as soil pH is an important variable, especially for bahiagrass. Herbicides will be evaluated for weed control effectiveness and turf tolerance. Studies will be conducted in rights-of-way where weed species are problematic. This information will be utilized by the chemical industry as well as FDOT management in considering chemical weed control programs.

Progress 10/01/12 to 09/30/17

Outputs
Target Audience:Target audiences include ranch managers, natural area managers, and personnel from local, state, and federal agencies. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Data from research plots have been provided through various outlets to county extension faculty as well as producers and agency peresonnel. Other avenues of dissemination have included one-on-one conversations with ranchers, agency personnel. A total of five field days were held over the period of this project for county extension faculty trainings on weed management in pastures and rangeland. How have the results been disseminated to communities of interest?Results have been disseminated through county extension meetings, field days, fact sheets, and online webinars as appropriate. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? 1. Examine the efficay of new and existing herbicide molecules for weed species common to pastures, rangeland, natural areas, and rights-of-way: Several experiments were conducted in pastures, rangeland, natural areas, and rights-of-way to determine the effect of aminocyclopyrachlor premixes on control of common pasture weeds as well as invasive species. These experiments were conducted were natural infestations of dogfennel, tropical soda apple, Brazilian peppertree, melaleuca, old world climbing fern, lead tree, lantana, and others. Data collected from these experiments were primairly visual control ratings using a scale of 0 to 100%, where 0 equals no control and 100 equals complete death. Aminocyclopyrachlor was found to be effective on many of these species, but may not be labeled for use in pastures for quite some time. However, it can be used in natural areas and rights-of-way for control of problematic species such as Brazilian peppertree, lantana, and Australian pine. A new dry formulation of fluroxypyr was evaluated for dogfennel control in bahiagrass pastures. Data revealed that the liquid formulation was superior to the dry formulation at low application rates, but both formulations performed similarly as rates increased. Additionally, a premix of fluroxypyr and 2,4-D was found to be a good tank-mix partner for GrazonNext HL herbicide. Additional experiments have determined that adjuvant selection for Crossbow herbicide, as well as experimental combinations of 2,4-D and bromoynil may be important for optimum dogfennel control in bahiagrass pastures. 2. Dermine the tolerance of forage and native species to new and existing herbicides: Limpograss is a tropical warm season grass that does not tolerate herbicide applications with the exception of dicamba and metsulfuron. Research was initiated to determine the tolerance of limpograss to several herbicides and were applied before,during or after fertilizer application, onto 12-, 24-, or 36-inch regrowth, or during the spring, summer and early winter. Previous observations that products, such as 2,4-D amine, seriously injure limpograss during the summer months, but little injury is observed in the winter and spring. Also, herbicide injury when applied to mature stands of limpograss tend to be less severe than new regrowth following cutting or grazing. It appears that mature stands of limpograss tolerate most herbicides, whereas herbicides applied to active regrowth causes substantial initial, yet temporary, injury. Biomass of limpograss plots 12 weeks after treatment was negatively impacted only by hexazinone and aminocyclopyrachlor for two growing seasons. Also, fertilizing after herbicide application appears to provide better regrowth of limpograss than when applied during or before herbicide application. The tolerance of Arachis pintoi, a seeded variety of perennial peanut to preemergence and postemergence herbicides was evaluated in 2015 and 2016. It has been determined that this species is tolerant to preemergent applications of Pursuit, Prowl H2O, and Impose herbicides. Postemergence applications of Impose and 2,4-D appear to be too injurious at emergence, but injury is acceptable when applied after 2 weeks following emergence. Postemergence applications of glyphosate and triclopyr were evaluated on four varieties of Arachis glabrata in 2016 and applied at various rates 2 weeks after clipping. Data revealed that 32 oz/A glyhposate resulted in no biomass reduction 60 days after treatment of long-established stands, but 20 oz/A resulted in approximately 20% less biomass of stands that were relatively young (<2 yrs old or disturbed root systems). 3. Develop management strategies for perennial weeds in improved forage systems: Broomsedge is becoming increasingly problematic in bahiagrass pastures in south Florida. Preliminary evidence suggests that either phosphorous or copper fertilization may help in increasing the competitive ability of bahiagrass over broomsedge species. Therefore, research was initiated in 2012 to begin to understand the effects of lime, nitrogen, phosphorous, potassium, and micronutrients on broomsedge stands in bahiagrass pastures. Broomsedge densities began to decline according to stand counts recorded in early 2015, but the response has been due to liming for purple bluestem. By 2016, purple bluestem densities were nearly 2-fold lower in plots receiving annuall applications of NPK fertilizer (applied at 50-25-50 lb/A, respectively). Bushy bluestem densities began to decline at a separate location within two years after applying annual applications of NPK fertlizer. In 2017, broomsedge densities increased at all locations; the reason for this increase is not understood, but could be related to the extreme drought recorded in central and south Florida in 2017. 4. Identify problematic weeds and control measures in rights-of-way: The current Florida Department of Transportation Maintenance Rating Program (MRP) handbook contains a list of fourteen plant species that are undesirable and should not be present in greater than 25% of a given area. This list of species has not been evaluated for a number of years and may not adequately describe the species that are most commonly problematic where turf scores have been consistently low. The hypotheses for this research were that the current list of undesired vegetation does not adequately cover the most problematic species in areas where turf conditions do not meet MRP standards, that undesired vegetation in South Florida is different from that in North Florida, and that soil pH may be the causative factor where weed invasion is extreme. The results of this research indicate that maidencane, castor bean, dogfennel, and tropical soda apple are not needed on the undesired list of vegetation in the MRP handbook. However, giant smutgrass, matchweed, teaweeds (southern and arrow leaf sida), white head broom and largeflower pusley should be considered as additional species on the MRP undesirable vegetation list. Considering that most of the species are present statewide, there is not a need to produce a list of district-specific species. However, a list of "weeds to watch" could be presented to each district and evaluated at a later date for inclusion in the MRP handbook. Amending soil pH by the addition of elemental sulfur could help in the sustainability of bahiagrass stands on rights-of-way; however, it may not be economically feasible. Therefore, other turfgrasses should be evaluated for sustainability on rights-of-way. A plant survey was conducted to determine the number of species and their associated root systems on the East Coast Protection Levee in Palm Beach County, Florida. Research on the number of weeds and their root systems was necessary as roots >1/2 inch in diameter are subject to "piping" and possible failure of the levee system during catastrophic flooding events. The current substrate of the levee system is limestone rock and/or shell, making the growth of a single desirable species difficult. A levee management plan was developed and provided to the South Florida Water Management District to ensure that species diversity if upheld while maintaining levee structure stability.

Publications

  • Type: Journal Articles Status: Awaiting Publication Year Published: 2017 Citation: Dias, J.L.C.S., A. Banu, B.P Sperry, S.F. Enloe, J.A. Ferrell, and B.A. Sellers. 2017. Relative activity of four triclopyr formulations. Weed Technol. In press.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Lastinger, C.A., J.L.C.S. Dias, B.A. Sellers, J.A. Ferrell, M.L.A. Silveira, and J.M.B. Venramini. Limpograss (Hemarthria altissima) tolerance to hexazinone. Weed Tehcnol. 31:682-688.
  • Type: Book Chapters Status: Published Year Published: 2017 Citation: 1. Rana, N., A.V. Varanasi, and B.A. Sellers. 2017. Effect of Environmental Factors on Weed Germination and Management. In: Biology, Physiology and Molecular Biology of Weeds, Mithila Jugulam (Ed.). CRC Press, Taylor & Francis Group, Boca Raton, FL.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Dias, J.L.C.S., A. Banu, S.F. Enloe, J.A. Ferrell, and B.A. Sellers. 2017. Relative activity of four triclopyr formulations. Southern Weed Science Society Annual Meeting. Birmingham, AL.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Dias, J.L.C.S. and B.A. Sellers. 2017. Effect of rainfall on smutgrass control with hexazinone. Southern Weed Science Society Annual Meeting. Birmingham, AL.


Progress 10/01/15 to 09/30/16

Outputs
Target Audience:The target audiences include ranchers, ranch managers, natural area managers, and personnel from local, state, and federal agencies. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Data from research plots have been provided through various outlets to county extension faculty as well as producers and agency personnel. Broomsedge plots at one location were viewed by clientele during the Range Cattle REC field day in October. How have the results been disseminated to communities of interest?Resultes have been disseminated through county extension meetings, field days, and through online webinars as appropriate. What do you plan to do during the next reporting period to accomplish the goals?Work will continue on broomsedge management in bahiagrass pastures. Data collected on perennial peanut tolerance to glyphosate and triclopyr will be utililized by the chemical industry for the development of 24c herbicide labels for applications of these herbicides onto perennial peanut hayfields.

Impacts
What was accomplished under these goals? There are two paths, with regards to weed control, that will help improve the profitability of animal production systems in Florida including testing and development of control strategies with and without herbicides as well as understanding the biology of weed/forage interactions. In natural areas and rights-of-way, invasive and native plants have a direct impact on desirable species. Invasive plants in natural areas have a direct impact on native flora and fauna and an indirect impact on the economy with regards to ecotourism. Weeds in rights-of-way impact desirable turf and/or public safety by interfering with the second year of this project no significant impact can be realized in this short amount of time. However, the research conducted under this project is beginning to provide answers necessary for ranchers to begin to formulate new ways of controlling native and invasive plants in pastures and rangeland. State and federal park personnel have become aware of some of the important invasive grass species commonly found in south Florida. A survey of weed species and their associate root systems will aid in the development of a management plan for the East Coast Protection levee in Florida, which will aid in improved protection from future flood events. Major goals of the project: 1. Examine the efficacy of new and existing herbicide molecules for weed species common to pastures, rangeland, natural areas, and right-of-way. Several experiments have been initiated in pastures, rangeland, natural areas, and rights-of-way to determine the effect of aminocyclopyrachlor premixes on control of common pasture weeds as well as invasive weeds. These experiments have been placed in natural infestations of Brazilian peppertree and lead tree. Data collected from these experiments are primarily visual control ratings using a scale of 0 to 100%, where 0 equals no control and 100 equals complete death. Aminocyclopyrachlor and premixes containing triclopyr, metsulfuron, or imazapyr have provided >80% control of both species for at least 1 year. A new formulation of fluroxypyr is currently under investigation for dogfennel control in bahiagrass pastures. Data has revealed that the liquid formulation is superior at low application rates, but both formulations perform similarly as rates are increased. Additionally, a premix of fluroxypyr and 2,4-D appears to be an extremely good tank-mix partner for GrazonNext HL herbicide. Additional experiments have examined adjuvant selection for Crossbow herbicide, as well as experimental combinations of 2,4-D and bromoxynil. Preliminary evidence suggests that combinations of these products provide satisfactory dogfennel control, but that adjuvant selection may be important for optimum control. 2. Determine the tolerance of forage and native species to new and existing herbicides. The tolerance of Arachis pintoi, a seeded variety of perennial peanut to preemergence and postemergence herbicides was evaluated in 2015 and 2016. It has been determined that this species is tolerant to preemergent applications of Pursuit, Prowl H2O, and Impose herbicides. Postemergence applications of Impose and 2,4-D appear to be too injurious at emergence, but injury is acceptable when applied after 2 weeks following emergence. Postemergence applications of glyphosate and triclopyr were evaluated on four varieties of Arachis glabrata in 2016 and applied at various rates 2 weeks after clipping. Data revealed that 32 oz/A glyhposate resulted in no biomass reduction 60 DAT of long-established stands, but 20 oz/A resulted in approximately 20% less biomass of stands that were relatively young (<2 yrs old or disturbed root systems). 3. Develop management strategies for perennial weeds in improved forage systems. Broomsedge is becoming increasingly problematic in bahiagrass pastures in south Florida. Preliminary evidence suggests that either phosphorous or copper fertilization may help in increasing the competitive ability of bahiagrass over broomsedge species. Therefore, research was initiated in 2012 to begin to understand the effects of lime, nitrogen, phosphorous, potassium, and micronutrients on broomsedge stands in bahiagrass pastures. Broomsedge densities began to decline according to stand counts recorded in early 2015, but the response has been due to liming for purple bluestem. By 2016, purple bluestem densities were nearly 2-fold lower in plots receiving annuall applications of NPK fertilizer (applied at 50-25-50 lb/A, respectively). Bushy bluestem densities began to decline at a separate location within two years after applying annual applications of NPK fertlizer. 4. Identify problematic weeds and control measures in rights-of-way. A plant survey was conducted to determine the number of species and their associated root systems on the East Coast Protection Levee in Palm Beach County, Florida. Research on the number of weeds and their root systems was necessary as roots >1/2 inch in diameter are subject to "piping" and possible failure of the levee system during catastrophic flooding events. The current substrate of the levee system is limestone rock and/or shell, making the growth of a single desirable species difficult. A levee management plan was developed and provided to the South Florida Water Management District to ensure that species diversity if upheld while maintaining levee structure stability.

Publications

  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Lastinger, C.A., B.A. Sellers, J.A. Ferrell, J.M.B. Vendramini, and M.L. Silveira. 2016. Limpograss tolerance to herbicides is affected by time of year, but not regrowth height or fertilizer application timing. Crop, Forage, Turfgrass Manage. doi:10.2134/cftm2016.04.0033.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Abe, D. G.g, B. A. Sellers, J. A. Ferrell, R. G. Leon, and D. C. Odero. 2016. Tolerance of bermudagrass and stargrass to aminocyclopyrachlor. Weed Technol. 30:499-505.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Abe, D. Gg., B. A. Sellers, J. A. Ferrell, R. G. Leon, and D. C. Odero. 2016. Weed control in Florida pastures with the use of aminocyclopyrachlor. Weed Technol. 30:271-278.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Durham, M. W.g, J. A. Ferrell, P. Minogue, G. MacDonald, and B. Sellers. 2016. Evaluation of aminocyclopyrachlor herbicide for turf tolerance and weed control on Florida roadside right-of-ways. Weed Technol. 30:190-197.
  • Type: Journal Articles Status: Accepted Year Published: 2016 Citation: Abe, D. G.g, B. A. Sellers, J. A. Ferrell, R. G. Leon, and D. C. Odero. 2016. Bahiagrass tolerance to aminocyclopyrachlor in Florida. Weed Technol. Accepted. 5 pages.
  • Type: Other Status: Published Year Published: 2016 Citation: Durham, M., J. Ferrell, and B. Sellers. 2016. Spiderwort control in hay fields and pastures. EDIS Publication AG407. http://edis.ifas.ufl.edu/ag407.
  • Type: Other Status: Published Year Published: 2016 Citation: Sellers, B. and J. McWhorter. 2016. Biology and management of whitehead broom in pastures. EDIS Publication AG409. http://edis.ifas.ufl.edu/ag409.
  • Type: Other Status: Published Year Published: 2016 Citation: Vendramini, J., S. Crawford, T. Prevatt, C. Kirby, B. Stice, M. Silveira, B. Sellers, and L. Wiggins. 2016. 2011 South Florida Beef Forage Survey Results. EDIS Publication AG410. http://edis.ifas.ufl.edu/ag410.
  • Type: Theses/Dissertations Status: Published Year Published: 2016 Citation: Martin, L.J. 2016. Tolerance of perennial peanuts (Arachis pintoi and Arachis glabrata) to PRE and postemergence herbicides. Thesis, University of Florida.
  • Type: Other Status: Published Year Published: 2016 Citation: 1. Dias, J.L.C.Sg, G.E. Duarte&, B.A. Sellers, and L.J. Marting. 2016. Control of cadillo (Urena lobata) in grazinglands. WSSA Abstracts. 56:46.
  • Type: Other Status: Published Year Published: 2016 Citation: 2. Martin, L.J.g, B.A. Sellers, J.A. Ferrell, J.M. Vendramini, R. Leon, and J.L.C.S. Diasg. 2016. Tolerance of Arachis pintoi to pre and post emergence herbicides. WSSA Abstracts. 56:166.
  • Type: Other Status: Published Year Published: 2016 Citation: 3. Fernandez, J.V.g, D.C. Odero, J.A. Ferrell, G.E. MacDonald, B.A. Sellers, and P.C. Wilson. 2016. Differential sensitivity of fall panicum (Panicum dichotomiflorum) populations to asulam. WSSA Abstracts. 56:309.


Progress 10/01/14 to 09/30/15

Outputs
Target Audience:The target audience for this project includes ranchers, ranch managers, natural area managers, and personnel from local, state, and federal agencies. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?County extension faculty were able to view the broomsedge plots during teh 2015 growing season, and preliminary data on broomsedge densities were shared. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?1. Examine the efficacy of new and existing herbicide molecules for weed species common to pastures, rangeland, natural areas, and right-of-way. Continue to analyze research data on aminocychlopyrachlor and the effect of herbicides on limpograss production for publication in refereed journals. 2. Determine the tolerance of forage and native species to new and existing herbicides. Continue to evaluate the effectiveness preemergence and postemergence herbicides on the viability of seeded perennial peanut. Publish data concerning the tolerance of bahiagrass to aminocyclopyrachlor. Continue collecting data on the tolerance of limpograss to various herbicides and analyze data for future publishing. 3. Develop management strategies for perennial weeds in improved forage systems. Continue to monitor established long-term broomsedge plots. 4. Identify problematic weeds and control measures in rights-of-way. Develop a vegetation management plan to maintain the levee system.

Impacts
What was accomplished under these goals? There are two paths, with regards to weed control, that will help improve the profitability of animal production systems in Florida including testing and development of control strategies with and without herbicides as well as understanding the biology of weed/forage interactions. In natural areas and rights-of-way, invasive and native plants have a direct impact on desirable species. Invasive plants in natural areas have a direct impact on native flora and fauna and an indirect impact on the economy with regards to ecotourism. Weeds in rights-of-way impact desirable turf and/or public safety by interfering with motorist line of sight or fire risk associated with transmission lines or by negatively affecting protective levee structures. In only the second year of this project no significant impact can be realized in this short amount of time. However, the research conducted under this project is beginning to provide answers necessary for ranchers to begin to formulate new waysof controlling native and invasive plants in pastures and rangeland. State and federal park personnel have become aware of some of the important invasive grass species commonly found in south Florida. A survey of weed species and their associate root systems will aid in the development of a management plan for the East Coast Protection levee in Florida, which will aid in improved protection from future flood events. Major goals of the project: 1. Examine the efficacy of new and existing herbicide molecules for weed species common to pastures, rangeland, natural areas, and right-of-way. Several experiments have been initiated in pastures, rangeland, natural areas, and rights-of-way to determine the effect of aminocyclopyrachlor premixes on control of common pasture weeds as well as invasive weeds. These experiments have been placed in natural infestations of several weed species including dogfennel, tropical soda apple, Brazilian peppertree, melaleuca, old world climbing fern, lead tree, and other species. Data collected from these experiments are primarily visual control ratings using a scale of 0 to 100%, where 0 equals no control and 100 equals complete death. A new formulation of fluroxypyr is currently under investigation for dogfennel control in bahiagrass pastures. Data has revealed that the liquid formulation is superior at low application rates, but both formulations perform similarly as rates are increased. Additionally, a premix of fluroxypyr and 2,4-D appears to be an extremely good tank-mix partner for GrazonNext HL herbicide. 2. Determine the tolerance of forage and native species to new and existing herbicides. Limpograss is a tropical warm season grass that does not tolerate herbicide applications with the exception of dicamba and metsulfuron. Research was initiated to determine the tolerance of limpograss to several herbicides and were applied before, during or after fertilizer application, onto 12-inch, 24-inch, or 36-inch regrowth, or during the spring, summer and early winter. Previous observations that products, such as 2,4-D amine, seriously injures limpograss during the summer months, but little injury is observed in the winter and spring. Also, herbicide injury when applied to mature stands of limpograss tend to be less severe than new regrowth following cutting or grazing. Since this research was initiated this growing season, little data have been collected. However, observationally, it appears that mature stands of limpograss tolerate most herbicides, whereas herbicides applied to active regrowth causes substantial initial injury. Biomass of limpograss plots 12 weeks after treatment was impacted only by hexazinone and aminocyclopyrachlor for two growing seasons. Also, fertilizing after herbicide application appears to provide better regrowth of limpograss than when applied during or before herbicide application. The tolerance of Arachis pintoi, a seeded variety of perennial peanut to preemergence and postemergence herbicides was evaluated in 2015. It has been determined that this species is tolerant to preemergent applications of Pursuit, Prowl H2O, and Impose herbicides. Postemergence applications of Impose and 2,4-D appear to be too injurious at emergence and 2 to 4 weeks after emergence. However, greenhouse research has indicated that more mature plants are tolerant of Impose, 2,4-D, and triclopyr. 3. Develop management strategies for perennial weeds in improved forage systems. Broomsedge is becoming increasingly problematic in bahiagrass pastures in south Florida. Preliminary evidence suggests that either phosphorous or copper fertilization may help in increasing the competitive ability of bahiagrass over broomsedge species. Therefore, research was initiated in 2012 to begin to understand the effects of lime, nitrogen, phosphorous, potassium, and micronutrients on broomsedge stands in bahiagrass pastures. Broomsedge densities began to decline according to stand counts recorded in early 2015, but the response has been due to liming or sulfur applications, depending on location and broomsedge species. 4. Identify problematic weeds and control measures in rights-of-way. An ongoing plant survey is being conducted to determine the number of species and their associated root systems on the East Coast Protection Levee in Palm Beach County, Florida. Research on the number of weeds and their root systems is necessary as roots >1/2 inch in diameter are subject to "piping" and possible failure of the levee system during catastrophic flooding events. The current substrate of the levee system is limestone rock and/or shell, making the growth of a single desirable species difficult. The ultimate goal of this research is to determine that the presence of the species is detrimental to the levee system. Over 50 species have been identified, with only two with root systems >1/2 inch in diameter. Future work will include continuation of the weed survey as well as determining an optimal vegetation management plan that will enhance the current vegetation on the levee system.

Publications

  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Rana, N., B. A. Sellers, J. A. Ferrell, G. E. MacDonald, M. L. Silveira, J. M. Vendramini. 2015. Integrated management techniques for long-term control of giant smutgrass (Sporobolus indicus var. pyramidalis in bahiagrass pasture in Florida. Weed Technol. 29:570-577.
  • Type: Journal Articles Status: Accepted Year Published: 2016 Citation: Abe, D. G., B. A. Sellers, J. A. Ferrell, R. G. Leon, and D. C. Odero. 2016. Weed control in Florida pastures using aminocyclopyrachlor. Weed Technol. In press.
  • Type: Journal Articles Status: Accepted Year Published: 2016 Citation: Abe, D. G., B. A. Sellers, J. A. Ferrell, R. G. Leon, and D. C. Odero. 2016. Tolerance of bermudagrass and stargrass to aminocyclopyrachlor. Weed Technol. In press.
  • Type: Other Status: Published Year Published: 2015 Citation: Sellers, B. A. and J. A. Ferrell. 2015. Weed management in pastures and rangeland - 2015. IFAS Publication SS-AGR-08. Gainesville: University of Florida Institute of Food and Agricultural Sciences. http://edis.ifas.ufl.edu/wg006.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Durham, M. W., J. A. Ferrell, and B. A. Sellers. 2015. Management of Opuntia spp. in Florida pastures. Proc. South. Weed Sci. Soc. 68:47.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Sellers, B. A. and J. A. Ferrell. 2015. Management of pawpaw in bahiagrass pastures. Proc. South. Weed Sci. Soc. 68:145.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Lastinger, C. A., B. A. Sellers, J. A. Ferrell. 2015. Influence of fertility and regrowth stage on Floralta limpograss tolerance to herbicide applications. Proc. South. Weed Sci. Soc. 68:232.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Sellers, B. A., J. A. Ferrell, and G. E. MacDonald. 2015. Control of Brazilian pepper-tree and Australian pine using aminocyclopyrachlor. Proc. Weed Sci. Soc. Amer. 55:178.
  • Type: Other Status: Published Year Published: 2015 Citation: MacKay, R., E. Jennings, B. Sellers, J. Ferrell, A. House. 2015. Creeing indigo, a poisonous plant of concern in Florida pastures. IFAS Publication SS-AGR-395. Gainesville: University of Florida Institute of Food and Agricultural Sciences. http://edis.ifas.ufl.edu/ag399.
  • Type: Other Status: Published Year Published: 2015 Citation: Sellers, B. and J. Ferrell. 2015. Soft rush (Juncus effusus) biology and control in pastures. IFAS Publication SS-AGR-325. Gainesville: University of Florida Institute of Food and Agricultural Sciences. http://edis.ifas.ufl.edu/ag335.
  • Type: Theses/Dissertations Status: Published Year Published: 2015 Citation: Lastinger, C. A. 2015. Limpograss (Hemarthria altissima) tolerance to herbicide applications (Master's thesis). University of Florida.


Progress 10/01/13 to 09/30/14

Outputs
Target Audience: The target audience for this project includes ranchers, ranch managers, natural area managers, and personnel from local, state, and federal agencies. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? County Extension faculty were able to view the plots treated with aminocyclopyrachlor (bahiagrass, stargrass, and bermudagrass) so that they have the knowledge of the safety of this herbicide to these forage species. They also were able to view the limpograss experiments so that they could see the differences in tolerance to the herbicide treatments. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? 1. Examine the efficacy of new and existing herbicide molecules for weed species common to pastures, rangeland, natural areas, and right-of-way. Continue to evaluate the effectiveness of aminocyclopyrachlor on various weed species, as well as analyze and publish data in refereed journals on those species that have been completed. 2. Determine the tolerance of forage and native species to new and existing herbicides. Publish data concerning the tolerance of forages to aminocyclopyrachlor. Continue collecting data on the tolerance of limpograss to various herbicides and analyze data for future publishing. 3. Develop management strategies for perennial weeds in improved forage systems. Continue to monitor established long-term broomsedge and smutgrass plots. 4. Identify problematic weeds and control measures in rights-of-way. Complete the plant survey on the East Coast Protection Levee and develop a vegetation management plan to maintain the levee system.

Impacts
What was accomplished under these goals? There are two paths, with regards to weed control, that will help improve the profitability of animal production systems in Florida including testing and development of control strategies with and without herbicides as well as understanding the biology of weed/forage interactions. In natural areas and rights-of-way, invasive and native plants have a direct impact on desirable species. Invasive plants in natural areas have a direct impact on native flora and fauna and an indirect impact on the economy with regards to ecotourism. Weeds in rights-of-way impact desirable turf and/or public safety by interfering with motorist line of sight or fire risk associated with transmission lines or by negatively affecting protective levee structures. In only the second year of this project no significant impact can be realized in this short amount of time. However, the research conducted under this project is beginning to provide answers necessary for ranchers to begin to formulate new ways of controlling native and invasive plants in pastures and rangeland. State and federal park personnel have become aware of some of the important invasive grass species commonly found in south Florida. A survey of weed species and their associate root systems will aid in the development of a management plan for the East Coast Protection levee in Florida, which will aid in improved protection from future flood events. Major goals of the project: 1. Examine the efficacy of new and existing herbicide molecules for weed species common to pastures, rangeland, natural areas, and right-of-way. Several experiments have been initiated in pastures, rangeland, natural areas, and rights-of-way to determine the effect of aminocyclopyrachlor premixes on control of common pasture weeds as well as invasive weeds. These experiments have been placed in natural infestations of several weed species including dogfennel, tropical soda apple, Brazilian peppertree, melaleuca, old world climbing fern, and other species. Data collected from these experiments are primarily visual control ratings using a scale of 0 to 100%, where 0 equals no control and 100 equals complete death. As many of these experiments will not be complete until one year following herbicide application, data have not been analyzed, but general observations from using aminocyclpyrachlor premixes in these different locations indicate that it will provide an additional herbicide for control of weeds in these environments. 2. Determine the tolerance of forage and native species to new and existing herbicides. The tolerance of bahiagrass, bermudagrass, and stargrass to the aminocyclopyrachlor premixes mentioned above was investigated in weed free pastures or hayfields. Biomass was collected from individually treated plots at 4 and 8 weeks after treatment. Data indicate that these premixes will be relatively safe to apply to all three forage species, except for the aminocyclopyrachlor-metsulfuron combination on ‘Pensacola’ bahiagrass. The aminocyclopyrachlor premixes caused some initial yield loss of bermudagrass and stargrass, however, treated plots greatly outyield the untreated checks by 8 weeks after treatment. These data indicate that aminocyclopyrachlor premixes that will be available to producers in the next couple of years will be viable alternatives for weed control with little impact on forage production. Limpograss is a tropical warm season grass that does not tolerate herbicide applications with the exception of dicamba and metsulfuron. Research was initiated to determine the tolerance of limpograss to several herbicides and were applied before, during or after fertilizer application, onto 12-inch, 24-inch, or 36-inch regrowth, or during the spring, summer and early winter. Previous observations that products, such as 2,4-D amine, seriously injures limpograss during the summer months, but little injury is observed in the winter and spring. Also, herbicide injury when applied to mature stands of limpograss tend to be less severe than new regrowth following cutting or grazing. Since this research was initiated this growing season, little data have been collected. However, observationally, it appears that mature stands of limpograss tolerate most herbicides, whereas herbicides applied to active regrowth causes substantial initial injury. Biomass of limpograss plots 12 weeks after treatment was impacted only by hexazinone and aminocyclopyrachlor for two growing seasons. Also, fertilizing after herbicide application appears to provide better regrowth of limpograss than when applied during or before herbicide application. 3. Develop management strategies for perennial weeds in improved forage systems. Broomsedge is becoming increasingly problematic in bahiagrass pastures in south Florida. Preliminary evidence suggests that either phosphorous or copper fertilization may help in increasing the competitive ability of bahiagrass over broomsedge species. Therefore, research was initiated in 2012 to begin to understand the effects of lime, nitrogen, phosphorous, potassium, and micronutrients on broomsedge stands in bahiagrass pastures. Since broomsedge is a short-lived perennial plant, results from this experiment will likely not be realized until 2015. However, there is an observational difference in bahiagrass stand and grazing with fertilizer plots compared to non-fertilized plots. Smutgrass is currently the number one invasive grass in perennial grass pastures and hayfields in Florida. Current research is investigating the effects of multi-year sequential applications of hexazinone at reduced rates in comparison to a one-time full rate of hexazinone. This research indicates that smutgrass density is the same when using ½-rate of hexazinone over two years compared to a full rate in one year 3 years after the initial treatment. Since hexazinone is an expensive herbicide, allowing ranchers to reduce the use rate over two years reduces annual costs and spreads out the risk of hexazinone failure from limited or excessive rainfall after application. 4. Identify problematic weeds and control measures in rights-of-way. An ongoing plant survey is being conducted to determine the number of species and their associated root systems on the East Coast Protection Levee in Palm Beach County, Florida. Research on the number of weeds and their root systems is necessary as roots >1/2 inch in diameter are subject to “piping” and possible failure of the levee system during catastrophic flooding events. The current substrate of the levee system is limestone rock and/or shell, making the growth of a single desirable species difficult. The ultimate goal of this research is to determine that the presence of the species is detrimental to the levee system. Over 50 species have been identified, with only two with root systems >1/2 inch in diameter. Future work will include continuation of the weed survey as well as determining an optimal vegetation management plan that will enhance the current vegetation on the levee system.

Publications

  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Sellers, B.A., S.R. Lancaster, and K.A. Langeland. 2014. Herbicides for postemergence control of mile-a-minute (Mikania micrantha). Invasive Plant Sci. Mgmt. 7:303-309.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Lastinger, C.A., B.A. Sellers, and J.A. Ferrell. 2014. Limpograss (Hemarthria altissima) tolerance to herbicide applications. Proc. South. Weed Sci. Soc. 67:61
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Abe, D.G., B.A. Sellers, J.A. Ferrell, R.G. Leon, and D.C. Odero. 2014. Forage tolerance to aminocyclopyrachlor. Proc. South. Weed Sci. Soc. 67:130.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Sellers, B.A. and J.A. Ferrell. 2014. Response of smutgrass (Sporobolus spp.) to management practices in Florida. Proc. South. Weed Sci. Soc. 67:263.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Durham, M.W., J.A. Ferrell, and B.A. Sellers. 2014. Management of Opuntia spp. in Florida pastures. Proc. South. Weed Sci. Soc. 67:266.


Progress 10/01/12 to 09/30/13

Outputs
Target Audience: The primary target audience for this award include ranchers and land managers, but often also includes personnel from state and federal agencies, county extension faculty, and youth. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? The research outlined in goals 1 through 3 will be continued so that information can be delivered to clientele.

Impacts
What was accomplished under these goals? Major goals of the project: 1. Examine the efficacy of new and existing herbicide molecules for weed species common to pastures, rangeland, natural areas, and right-of-way. Several experiments have been initiated in pastures, rangeland, natural areas, and rights-of-way to determine the effect of aminocyclopyrachlor premixes on control of common pasture weeds as well as invasive weeds. These experiments have been placed in natural infestations of several weed species including dogfennel, tropical soda apple, Brazilian peppertree, melaleuca, old world climbing fern, and other species. Data collected from these experiments are primarily visual control ratings using a scale of 0 to 100%, where 0 equals no control and 100 equals complete death. As many of these experiments will not be complete until one year following herbicide application, data have not been analyzed, but general observations from using aminocyclpyrachlor premixes in these different locations indicate that it will provide an additional herbicide for control of weeds in these environments. 2. Determine the tolerance of forage and native species to new and existing herbicides. The tolerance of bahiagrass, bermudagrass, and stargrass to the aminocyclopyrachlor premixes mentioned above was investigated in weed free pastures or hayfields. Biomass was collected from individually treated plots at 4 and 8 weeks after treatment. Data indicate that these premixes will be relatively safe to apply to all three forage species, except for the aminocyclopyrachlor-metsulfuron combination on ‘Pensacola’ bahiagrass. The aminocyclopyrachlor premixes caused some initial yield loss of bermudagrass and stargrass, however, treated plots greatly outyield the untreated checks by 8 weeks after treatment. These data indicate that aminocyclopyrachlor premixes that will be available to producers in the next couple of years will be viable alternatives for weed control with little impact on forage production. Limpograss is a tropical warm season grass that does not tolerate herbicide applications with the exception of dicamba and metsulfuron. Research was initiated to determine the tolerance of limpograss to several herbicides and were applied before, during or after fertilizer application, onto 12-inch, 24-inch, or 36-inch regrowth, or during the spring, summer and early winter. Previous observations that products, such as 2,4-D amine, seriously injures limpograss during the summer months, but little injury is observed in the winter and spring. Also, herbicide injury when applied to mature stands of limpograss tend to be less severe than new regrowth following cutting or grazing. Since this research was initiated this growing season, little data have been collected. However, observationally, it appears that mature stands of limpograss tolerate most herbicides, whereas herbicides applied to active regrowth causes substantial initial injury. Biomass of limpograss plots 12 weeks after treatment was impacted only by hexazinone and aminocyclopyrachlor. Also, fertilizing after herbicide application appears to provide better regrowth of limpograss than when applied during or before herbicide application. 3. Develop management strategies for perennial weeds in improved forage systems. Broomsedge is becoming increasingly problematic in bahiagrass pastures in south Florida. Preliminary evidence suggests that either phosphorous or copper fertilization may help in increasing the competitive ability of bahiagrass over broomsedge species. Therefore, research was initiated in 2012 to begin to understand the effects of lime, nitrogen, phosphorous, potassium, and micronutrients on broomsedge stands in bahiagrass pastures. Since broomsedge is a short-lived perennial plant, results from this experiment will likely not be realized until 2015. However, there is an observational difference in bahiagrass stand and grazing with fertilizer plots compared to non-fertilized plots. Smutgrass is currently the number one invasive grass in perennial grass pastures and hayfields in Florida. Current research is investigating the effects of multi-year sequential applications of hexazinone at reduced rates in comparison to a one-time full rate of hexazinone. This research indicates that smutgrass density is the same when using ½-rate of hexazinone over two years compared to a full rate in one year 3 years after the initial treatment. Since hexazinone is an expensive herbicide, allowing ranchers to reduce the use rate over two years reduces annual costs and spreads out the risk of hexazinone failure from limited or excessive rainfall after application. 4. Identify problematic weeds and control measures in rights-of-way. The current Florida Department of Transportation Maintenance Rating Program (MRP) handbook contains a list of fourteen plant species that are undesirable and should not be present in greater than 25% of a given area. This list of species has not been evaluated for a number of years and may not adequately describe the species that are most commonly problematic where turf scores have been consistently low. The hypotheses for this research are that the current list of undesired vegetation does not adequately cover the most problematic species in areas where turf conditions do not meet MRP standards, that undesired vegetation in South Florida is different from that in North Florida, and that soil pH may be the causative factor where weed invasion is extreme.The results of this research indicate that maidencane, castor bean, dogfennel, and tropical soda apple are not needed on the undesired list of vegetation in the MRP handbook. However, giant smutgrass, matchweed, teaweeds (southern and arrow leaf sida), white head broom and largeflower pusley should be considered as additional species on the MRP undesirable vegetation list. Considering that most of the species are present statewide, there is not a need to produce a list of district-specific species. However, a list of “weeds to watch” could be presented to each district and evaluated at a later date for inclusion in the MRP handbook. Amending soil pH by the addition of elemental sulfur could help in the sustainability of bahiagrass stands on rights-of-way; however, it may not be economically feasible. Therefore, other turfgrasses should be evaluated for sustainability on rights-of-way.

Publications

  • Type: Book Chapters Status: Published Year Published: 2013 Citation: MacDonald, G. E., L. A. Gettys, J. A. Ferrell, and B. A. Sellers. 2013. Herbicides for Natural Area Weed Management. In: Herbicides  Current Research and Case Studies in Use, Dr. Andrew Price (Ed.). InTech, Available from: http://www.intechopen.com/books/herbicides-current-research-and-case-studies-in-use/herbicides-for-natural-area-weed-management
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Rana, N., B. A. Sellers, J. A. Ferrell, G. E. MacDonald, M. L. Silveira, and J. M. Vendramini. 2013. Impact of soil pH on bahiagrass competition with giant smutgrass (Sporobolus indicus var. pyramidalis) and small smutgrass (Sporobolus indicus var. indicus). Weed Sci. 61:109-116.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Abe, D. G., B. A. Sellers, J. Ferrell. 2013 Tolerance of sub-tropical and tropical forages to aminocyclopyrachlor. Proc. South. Weed Sci. Soc. 66:21.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Sellers, B. A., D. G. Abe, and J. Ferrell. 2013. Control of various pasture weeds with aminocyclpyrachlor. Proc. South. Weed Sci. Soc. 66:265.
  • Type: Other Status: Published Year Published: 2013 Citation: Sellers, B. and J. Ferrell. 2013 (Revised). Weed management in pastures and rangeland  2013. EDIS Publication WG006. http://edis.ifas.ufl.edu/wg006.