Pasture Weeds

Several tactics must be utilized to combat weeds in pastures. First and foremost, one must be able to identify the weed so that the appropriate control tactic can be implemented.

A key component to using herbicides in pastures is that they have good activity and are safe to our forage crops. One must also realize that there are environmentally safe alternatives in weed control. Therefore, weed management in pastures and rangeland can include methods of chemical, biological and mechanical control.

• Using SolviNix™ for Tropical Soda Apple Control

  • SolviNix™: A Natural Biological Herbicide to Control Tropical Soda Apple

    Tropical soda apple (Solanum viarum; TSA) is susceptible to Tobacco mild green mosaic tobamovirus (TMGMV), a plant virus that naturally occurs in Florida. Unlike other known plant viruses that cause non-lethal diseases on TSA, TMGMV elicits a strong hypersensitive response from TSA, killing the entire plant.

    Pasture Weeds SolviNix™: A Natural Biological Herbicide to Control Tropical Soda Apple Tropical soda apple (Solanum viarum; TSA) is susceptible to Tobacco mild green mosaic tobamovirus (TMGMV), a plant virus that naturally occurs in Florida. Unlike other known plant viruses that cause non-lethal diseases on TSA, TMGMV elicits a strong hypersensitive response from TSA, killing the entire plant. Through extensive testing, we have confirmed that TMGMV can be used safely and effectively as a bioherbicide for TSA. We have developed an industrial process to mass-produce the virus and formulate it into a liquid concentrate, SolviNix™LC. Currently SolviNix™LC is available for field testing in Florida under an Experimental Use Permit; our petition for a Section 3 registration is under review.

    SolviNix™ LC is effective at low a.i. rates of 200 to 800 mg per acre. For spot treatment, it can be applied with a backpack sprayer set to deliver at 60 to 80 psi. For TSA control over large areas, an herbicide wiper is effective. Our aim is to offer SolviNix™ LC as a TSA management option for livestock and dairy operations and natural areas.

    Presenters

    • Mark Elliott is a Senior Biological Scientist in the Department of Plant Pathology. He has worked on viruses of ornamentals, peanuts and soybeans. He is currently working on the development and application of Tobacco Mild Green Mosaic virus as a biological control agent for tropical soda apple, Solanum viarum.

    Publications

    • SolviNix™, a Natural Biological Herbicide to Control Tropical Soda Apple [195KB]

• Tropical Soda Apple Beetle

  • Tropical soda apple, Solanum viarum, is a South American plant which invaded Florida in the 1980s. It is primarily a problem in rangelands and pastures where it displaces forage grasses resulting in lower stocking rates. Cattle do not feed on the foliage, but consume the fruits, thereby transporting seeds to new areas in their digestive tracks.

    Gratiana boliviana, a South America beetle, has been introduced into Florida as a biological control agent of tropical soda apple. The beetle, which has been released at several hundred locations in Florida, has been shown to lower the density and fruit production of tropical soda apple.

    Presenters

    • Bill Overholt is an Associate Professor at the University of Florida’s Indian River Research and Education Center in Fort Pierce, Florida. Dr. Overholt’s research is focused on biological control of invasive plants using natural enemies found in the plant’s native range. He conducts foreign exploration for natural enemies, studies their biology in a quarantine laboratory, and evaluates their performance once released in Florida. His program is currently targeting Hydrilla verticillata, Brazilian peppertree, air potato and tropical soda apple.

    Publications

    • Biological Control of Tropical Soda Apple using the beetle Gratiana boliviana [196KB]
    • Biology of Gratiana boliviana, the First Biocontrol Agent Released to Control Tropical Soda Apple in the USA
    • Classical Biological Control of Tropical Soda Apple in the USA

• Forage

  • Dicamba (Banvel) has been the standard recommendation for weed control in limpograss, because Weedmaster contains 2,4-D, which has been reported to cause significant limpograss injury. Over the past couple of years, we have had several herbicides labeled in the pasture market including: Cimarron, Telar, Pasturegard, Overdrive, and Milestone. The tolerance of limpograss to these herbicides needs to be understood, and the timing of application generally influences the safety of these herbicides on limpograss.

    Presenters

    • Dr. Brent Sellers is an assistant professor of Weed Science at the Range Cattle Research and Education Center. He has a state-wide Extension appointment in the areas of pasture and rangeland weed control as well as invasive weed control. His research program focuses on new weed control strategies in pastures, weed competition in pastures, and the control of invasive grasses in pastures as well as native areas. Dr. Sellers' work in natural areas includes the control of non-native grasses, West Indian marsh grass and para grass.

    Publications

    • Forage Grass Tolerance to Pasture Herbicides
    • Limpograss Tolerance to Herbicides [196KB]

• Climbing Fern

  • Two non-native, invasive species of climbing ferns are known from Florida. In north Florida, Japanese climbing fern (Lygodium japonicum) is most invasive. In south Florida, Old World climbing fern (Lygodium microphyllum) is most invasive. Both species grow into the canopy of trees, often form dense ground cover eliminating most native vegetation, and thrive in mesic or hydric soils. It is in the central Florida region where both species occur together possibly making management of these invasive plants more difficult.

    Presenters

    • Jeff Hutchinson earned a BS degree (1994) in Wildlife Ecology/Forestry from the University of Florida and a MS degree (1998) in Forestry from the University of Kentucky, and is currently pursuing a Ph.D. degree in Agronomy with an emphasis on Weed Science at the University of Florida. Prior to returning back to college in 1990, he served six years in the US Marine Corps stationed in California, Hawaii and Japan. Between 1998 and 2004, Jeff worked as a district biologist for the Florida Park Service in Hobe Sound and as land manager at Archbold Biological Station in Lake Placid.

    Publications

    • Natural Area Weeds: Old World Climbing Fern (Lygodium microphyllum)

• Smutgrass

  • Smutgrass is an exotic, invasive perennial grass species that ranchers have been fighting over the last 50 years. Smutgrass control is an expensive venture, costing anywhere from $26 to $36 per acre to control small and giant smutgrass, respectively.

    We are consistently looking for ways to optimize smutgrass control with Velpar. One possible way is to look at the addition of surfactants to Velpar. Specifically, does the addition of a surfactant to Velpar increase smutgrass control compared to Velpar alone? What about other adjuvants?

    Presenters

    • Barton Wilder obtained his M.S. degree in Agronomy in 2009. His research project examined the most effect rate of Velpar for small and giant smutgrass control in pastures. He also examined the effects of environmental conditions on smutgrass seed germination and optimization of smutgrass control with Velpar using various surfactants. Currently, Barton is the Ag and Natural Resource Agent in Alachua County.

    Publications

    • Smutgrass Control: Do Surfactants Matter? [200KB]
    • Smutgrass Control in Perennial Grass Pastures

• Stargrass

  • Weedy grasses are commonly problematic in bermudagrass and stargrass fields. Bahiagrass, crabgrass, and vaseygrass are the most common offenders. Therefore, it would be greatly beneficial to determine if these grasses can be controlled, or suppressed, until stargrass gains a competitive advantage.

    Presenters

    • Dr. Jason Ferrell is an Extension Weed Specialist based in Gainesville, FL. His research program emphasizes field aspects of weed science covering weed biology and management in agronomic crops, forages, and highway rights-of-ways.

    Publications

    • Controlling Weedy Grasses in Stargrass Pastures [196KB]

• Weed Identification

  • Proper weed identification is a must for optimizing weed control operations. One of the educational efforts that we use at the Range Cattle Research and Education Center is the Forage and Weed Nursery. This nursery contains approximately 40 forages and 165 weed species commonly found in Florida pastures and rangeland. Funds for building the nursery were provided by Integrated Pest Management Florida, the South Florida Beef-Forage Program, and Dow AgroSciences.

    Presenters

    • Greg MacDonald is an associate professor of Weed Science in the Agronomy Dept at the University of Florida. He teaches the undergraduate and several graduate level weed science courses and has recently begun teaching on-line courses. His research focus is weed physiology and the interactions of herbicides with plants. He also works on cogongrass management, physiology and restoration. He also cooperates in the management of natalgrass, torpedograss and other perennial grassy invasive species.

    Publications

    • Pasture Weeds poster [1.69MB]
    • Weed Management in Pastures and Rangeland