Biology and Management of Tropical Whiteweed (Ageratum conyzoides) in Citrus Groves

This 3-page document profiles tropical whiteweed, a common weed of agriculture crops, wetlands, roadsides, and pastures in many parts of the world, and discusses how to manage this weed in citrus groves. Written by Ramdas Kanissery, Brent Sellers, and Steve Futch and published by the UF/IFAS Horticultural Sciences Department, January 2019.

Integrated Management of Non-Native Plants in Natural Areas of Florida

Air potato. Invasive yam species, perennial vine, poison plants. UF/IFAS Photo: Thomas Wright.

While natural areas are conservation lands that have been set aside for the purpose of preserving (or restoring) native plant and animal communities, they do require active management. One of the greatest management issues in natural areas is invasive plants. This 35-page publication provides land managers in Florida with current methods used to manage non-native plants. Written by Stephen F. Enloe, Ken Langeland, Jason Ferrell, Brent Sellers, and Greg MacDonald, and published by the UF/IFAS Agronomy Department, revised July 2018.

Brunswickgrass or Paspalum nicorae: A Weed Contaminant in Southern Pastures and Bahiagrass Seed Production Fields

Closely grazed bahiagrass pasture with patches of brunswickgrass in late September (toward the end of the growing season) in Levy County, FL.

Brunswickgrass (Paspalum nicorae Parodi) is becoming a problematic weed in summer perennial grass pastures in the Southeast. The plant is competitive with bahiagrass
and bermudagrass. Since it is less palatable, it can eventually dominate a perennial grass pasture. Brunswickgrass has become naturalized and has reportedly contaminated bahiagrass seed fields and pastures in the southeastern states, including some of the important counties for seed production in Florida, such as Gilchrist, Levy, Alachua, Citrus, and Sumter. This 4-page fact sheet provides an overview of brunswickgrass and discusses its appearance, variety/germplasm, and management. Written by Ann Blount, Marcelo Wallau, Brent Sellers, Dennis Hancock, Leanne Dillard, Jose Dubeux, Cheryl Mackowiak, Joao Vendramini, and Clay Cooper, and published by the UF/IFAS Agronomy Department, April 2018.

Herbicide Residues in Manure, Compost, or Hay

Compost bin.

When purchasing compost, it is important to understand that some manure-based products can contain herbicide residues that can affect the growth of certain plants. Manure from animals that have been fed forage treated with aminopyralid or other closely related herbicides, such as clopyralid or picloram, can be contaminated with these herbicides, which severely restrict the growth of legume and solanaceous crops and other broadleaf plants. This 3-page fact sheet discusses aminopyralid, compost, questions to ask when purchasing bulk compost or mulch, conducting a bioassay, aminopyralid injury symptoms, and steps to consider if contaminated manure or compost has been added to a garden or field site. Written by Jason Ferrell, Peter Dittmar, and Brent Sellers, and published by the UF Agronomy Department, May 2017.

2011 South Florida Beef Forage Survey Results

Young heifers at the Range Cattle Research Station. These beef cows are all at least 3/4 Angus. They are part of an attempt to create a white Angus breed. During the summer the white cows, coined "white Angus" by the researchers in Ona, have a body temperature that is one degree cooler than the traditional black Angus. UF/IFAS Photo: Sally Lanigan.UF/IFAS Extension faculty and state specialists involved in the UF/IFAS South Florida Beef-Forage Program (SFBFP), in conjunction with the UF/IFAS Program Evaluation and Organizational Development unit, created a survey in 1982 that is used to evaluate ranch management practices. The survey is updated and distributed every five years to ranchers in 14 south Florida counties: Charlotte, Collier, DeSoto, Glades, Hardee, Hendry, Highlands, Hillsborough, Lee, Manatee, Martin, Okeechobee, Polk, and Sarasota. There were 102 anonymous responses in 2011. This 6-page fact sheet discusses characteristics of beef operations in south Florida, reproduction, production, marketing, herd health, nutrition, forage production, and environment. Written by Sonja Crawford, Christa Kirby, Tycee Prevatt, Brent Sellers, Maria Silveira, Bridget Stice, Joao Vendramini, and Lindsey Wiggins, and published by the UF Agronomy Department, October 2016.

Biology and Management of Whitehead Broom in Pastures

Whitehead broom growing in a pasture. Note the opposite to whorled leaf arrangement, linear leaves, and clusters of white flowers at the nodes.

Whitehead broom, also known as shrubby false buttonweed or southern larraflower, is becoming problematic in south Florida pastures, hayfields, and rights-of-way. This 2-page fact sheet discusses a few options to control this species. Written by Brent Sellers and James McWhorter, and published by the UF Agronomy Department, August 2016.

Cressleaf Groundsel (Butterweed) Identification and Management in Pastures

Butterweed flowers.Butterweed is a winter annual that is toxic to both cattle and horses. This 2-page fact sheet provides an overview of the plant as well as herbicide recommendations. Written by Brent Sellers and Jay Ferrell, and published by the UF Agronomy Department, May 2016.

Spiderwort Control in Hay Fields and Pastures

Spiderwort can be easily identified by its clusters of colorful flowers with three petals.
Spiderwort is a native perennial species found throughout the eastern half of the US. The plant’s large, fleshy stem creates problems for hay production. This 2-page fact sheet provides a brief overview of the plant as well as information on control through herbicide use. Written by Michael Durham, Jason Ferrell, and Brent Sellers, and published by the UF Agronomy Department, May 2016.

Suggested Weed Control Programs for Citrus

Orange grove.
Weed management is an important component of citrus production. The selection and implementation of a weed management program can lead to both economic and environmental returns. This three-page fact sheet details how to manage weeds in both young and mature groves, the differences in weed control programs between interior areas and coastal or flatwoods areas, how to control weeds after a freeze, and common ways that herbicides are misused. Written by Stephen H. Futch and Brent Sellers, and published by the Horticultural Sciences Department.

Maximizing Weed Control in Florida Citrus

oranges on the tree with orchard in background
With Florida citrus growers and production managers being “squeezed” between rising production prices and declining yields from citrus greening, there’s more call than ever to reduce citrus production costs. Controlling weeds is a major expense, amounting to 11% of the total $2,278 annual production cost per acre for the 2014–2015 season. This 3-page fact sheet teaches the six essential components of an effective weed-management program to help maintain the profitability of this vital Florida industry. Written by Stephen H. Futch and Brent Sellers and published by the Horticultural Sciences Department.

Creeping Indigo, A Poisonous Plant of Concern in Florida Pastures

Flowers of creeping indigo arise from the base of the leaves and are pink to salmon in color.A recent rise in suspected horse poisonings has brought new attention to creeping indigo (Indigofera spicata), a toxic plant which has reportedly been in Florida for as long as 90 years. This new 5-page fact sheet covers plant description, signs of creeping indigo toxicity, and roles of creeping indigo’s toxins, as well as treatment and management. Written by Robert MacKay, Ed Jennings, Brent Sellers, Jason Ferrell, and Amanda House, and published by the UF Department of Agronomy, August 2015.

Smutgrass Control in Perennial Grass Pastures

Figure 1. Smutgrass infestations are common in bahiagrass pastures throughout Florida. Smutgrass is a serious weed of improved perennial grass pastures, roadsides, natural areas, and waste areas in Florida. A 2003 survey found that smutgrass was second only to tropical soda apple as the most problematic weed species in Florida pastures, but now that practices to control tropical soda apple have been widely adopted in Florida, smutgrass is likely the most problematic weed species in Florida pastures today. This 4-page fact sheet was written by Brent Sellers, J. A. Ferrell, and N. Rana, and published by the UF Department of Agronomy, January 2015. (Photo Credit: B. Sellers, UF/IFAS)

Managing Against the Development of Herbicide-Resistant Weeds: Sugarcane

Figure 1. Sugarcane rows in the Everglades Agricultural Area (EAA) following herbicide application and cultivation.Profitable sugarcane production in Florida requires effective weed management. Herbicides provide an efficient and cost-effective means of weed control, but excessive use of a single herbicide or group of herbicides with the same mechanism of action has resulted in the development of herbicide-resistant weeds. In crops such as sugarcane where a limited number of herbicides are registered, the loss of a single effective herbicide can be very costly. Thus, it is critical to manage herbicides in order to prevent or delay the development of herbicide-resistant weed populations. This 4-page fact sheet lists herbicides by group number, mechanism of action, chemical family, common name, and trade name. Written by D.C. Odero, B.A. Sellers, J.A. Ferrell, and G.E. MacDonald, and published by the UF Department of Agronomy, October 2014.

Identification and Control of Coral Ardisia (Ardisia crenata): A Potentially Poisonous Plant.

Figure 4. Coral ardisia has bright red berries. It is thought that livestock died after consuming the berries in 2001 and 2007 in Florida.Coral ardisia, also known as coral berry, spice berry, and scratchthroat, was introduced to Florida in the early 1900’s for ornamental purposes. Since then, it has escaped cultivation, and it is found in hardwood hammocks and other moist, natural-wooded areas and grazing lands. Although there is no published literature supporting the theory that coral ardisia is toxic, it is suspected that the berries and/or foliage are poisonous to livestock, pets, and humans. This 3-page fact sheet was written by B. A. Sellers, Sarah Lancaster, K. A. Langeland, J.A. Ferrell, Michael Meisenberg, and J. Walter, and published by the UF Department of Agronomy, November 2013.

Wildland Weeds: Paragrass, Urochloa mutica (SSAGR370/AG375)

Figure 1.  Panicle-like inflorescence of Urochola mutica composed of false spikes.Paragrass (also referred to as Californiagrass) is thought to have been introduced into Florida sometime in the late 1870s as a forage plant. The semiaquatic grass is a native of tropical Africa, and today it is established in both hemispheres in tropical and subtropical regions as a highly palatable fodder. The grass is established in regions of poorly drained soils and along freshwater shorelines in Alabama, Florida, Hawaii, Maryland, Oregon, South Carolina, and Texas. It is an extremely aggressive competitor that can displace many shoreline emergent plants and plants in cultivated or disturbed sites associated with moist soil. Paragrass becomes readily established in wet soils along shorelines where it can form large monocultures. This 4-page fact sheet was written by L. T. Markle, B. A. Sellers, and W. A. Overholt, and published by the UF Department of Agronomy, April 2013.

Classical Biological Control of Tropical Soda Apple with Gratiana boliviana (ENY865/IN971)

Figure 4. South Florida Water Management District staff member, Terri Torrens, releasing Gratiana boliviana adults on a tropical soda apple plant.Tropical soda apple is a prickly shrub native to South America. First reported in Glades Co., Florida in 1988, it later spread to Georgia, Alabama, Louisiana, Texas, Mississippi, Tennessee, North Carolina, and South Carolina. It is a major problem in pastures and conservation areas. Negative impacts of tropical soda apple include reduction of cattle stocking rates, competition with native plants, and the costs associated with its control. Dense thickets of the weed also can disrupt the movement of wildlife. This 4-page fact sheet provides a summary of the major steps of the successful biological control program against tropical soda apple in Florida. The article covers the importance of the weed, identification and biology of the biological control agent, rearing and release efforts, establishment and impact, and efforts to communicate the outcomes of the program to stakeholders. Written by R. Diaz, J. Medal, K. Hibbard, A. Roda, A. Fox, S. Hight, P. Stansly, B. Sellers, J. Cuda and W. A. Overholt, and published by the UF Department of Entomology and Nematology, November 2012.

Identification and Control of Southern Sandbur (Cenchrus echinatus L.) in Hayfields (SSAGR364/AG373)

Figure 1.  Southern sandbur.Southern sandbur is an annual grass that grows in pastures and cropland throughout the warm areas of the southern United States from Virginia to California. This native grass is adapted to dry, sandy soils and has a shallow, fibrous root system. It can easily invade a poorly managed field, diminishing the quality of a hay crop or grazing pasture. Southern sandbur seeds start to germinate in late spring, and germination continues through the summer and fall. Flowering occurs in late fall, and growth is consistent until the first frost. This 2-page fact sheet was written by Hunter Smith, Jason Ferrell, and Brent Sellers, and published by the UF Department of Agronomy, December 2012.

Cogongrass (Imperata cylindrica) Biology, Ecology, and Management in Florida Grazing Lands (SSAGR52/WG202)

Figure 1. Cogongrass plants are yellow to green in color. Note that the edges of the leaf tend to have more yellow than green.Cogongrass is found on every continent and is considered a weedy pest in 73 countries. In the U.S., cogongrass is found primarily in the Southeast. It was accidentally introduced into Alabama in the early 1900s, and purposely introduced as a potential forage and soil stabilizer in Florida (and other states) in the 1930s and early 1940s. However, soon after investigations began it was realized that cogongrass could be a weedy pest. Since its introduction, cogongrass has spread to nearly every county in Florida. In some cases, it has completely taken over pastures so that it is the only species present. This is a common thread where cogongrass invades; it quickly displaces desirable species and requires intensive management. This 5-page fact sheet was written by B. A. Sellers, J. A. Ferrell, G. E. MacDonald, K. A. Langeland, and S. L. Flory, and published by the UF Department of Agronomy, August 2012.

Identification and Control of Johnsongrass, Vaseygrass, and Guinea Grass in Pastures (SSAGR363/AG372)

Johnsongrass is a common weed throughout the South and Midwest. People often incorrectly call any weed johnsongrass, but it is one of three grasses found in Florida pastures. Knowing the differences between johnsongrass, vaseygrass, and guinea grass will help with proper weed management. This 3-page fact sheet was written by H. Smith, J. Ferrell, and B. Sellers, and published by the UF Agronomy Department, August 2012.

Control of Lantana in Pastures (SSAGR359/AG368)

Figure 2. Lantana flowers of (A) purple/white and (B) red/yellow are common.Lantana is currently one of the top 10 most troublesome weeds in Florida. Although it is still sold as an ornamental, commercial varieties are sterile and considered to be non-invasive. It can quickly invade disturbed sites by producing plant toxins in its roots and stems, that either slow the growth of other plants or totally remove them. These leaf toxins are damaging to grazing animals. If animals consume the leaves, they often begin to show symptoms of skin peeling or cracking. Once animals show these symptoms, there is little or no treatment that can reverse the process. Although lantana’s leaves are poisonous, its berries are not. Birds readily consume the fruit and disperse the seed. This 2-page fact sheet was written by J. Ferrell, B. Sellers, and E. Jennings, and published by the UF Department of Agronomy, February 2012.