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Publication #ENH1270

Biology and Management of Ragweed Parthenium (Parthenium hysterophorous L.) in Ornamental Crop Production1

Debalina Saha, Chris Marble, Robert H. Stamps, Shawn Steed, and Nathan S. Boyd2

Species Description

Class: Dicotyledonous plant

Family: Asteraceae

Other Common Names: False ragweed, Ragweed parthenium, Santa Maria feverfew, Santa-Maria, Whitetop weed, Famine weed, and Congress weed

Life Span: Long-lived annual herb

Habitat: Occurs in semi-arid, subtropical, tropical, and warmer temperate regions. It is found on roadsides, along railways, pastures, grasslands, seasonal flood plains, open woodlands, riparian zones (banks of water courses), waste areas, disturbed sites, lawns, gardens, and multiple crops. It is particularly aggressive in disturbed and degraded pastures in semi-arid environments. In Florida nurseries, it is commonly found in non-crop areas, ditch banks, and in any area in which the soil has been disturbed.

Distribution: Ragweed parthenium is thought to have originated from the area surrounding the Gulf of Mexico and is native to Central and South America (Rollins 1950). Since the 1970s, it has spread extensively and rapidly in many parts of the world (Evans 1997).

Growth Habit: Erect (upright), much-branched herbaceous plant that forms a basal rosette of leaves during the juvenile phase (Figure 1). It usually grows 1.5 to 4.2 feet tall, but can occasionally reach up to 6 feet or more in height.

Figure 1. 

Ragweed parthenium growing in a pot. Note the upright growth habit and the basal rosette leaves.


Credit:

Annette Chandler, UF/IFAS


[Click thumbnail to enlarge.]

Seedling: Rosette basal leaves; pinnatifid (lobes on the leaf blade less than half way down toward the midrib) to bipinnatifid (doubly pinnatifid); pubescence (hairy) on stems and leaves (Figure 2).

Figure 2. 

Ragweed parthenium seedlings. Note the lobes on the leaf blade less than half way down towards the midrib.


Credit:

Annette Chandler, UF/IFAS


[Click thumbnail to enlarge.]

Shoot: Stems are erect, commonly 11 to 40 inches tall, hirsute (hairy), octangular (eight angles or edges), and grooved, with panicle-like branching, longitudinally striate. Leaves are simple, alternate, 1 to 7 inches long, 0.5 to 4 inches wide, whitish green, becoming smaller towards the top of the branches. The surfaces of the leaves and the stems are covered with white trichomes (hairs) (Kaur et al. 2014).

Roots: Fibrous roots develop from a deep taproot system that can extend up to 6 feet in length (Kaur et al. 2014).

Inflorescence: A loose terminal panicle, 3–5 mm in diameter, with several pentagonal and hemispherical heads (capitula) that are slightly convex on top, and short slender pedicels 3–20 mm long, densely pubescent. Disk florets are whitish in color and 3–5 mm wide (Figure 3).

Figure 3. 

Ragweed parthenium in flower. Note the inflorescence with several pentagonal and hemispherical heads.


Credit:

Annette Chandler, UF/IFAS


[Click thumbnail to enlarge.]

Fruit and Seeds: Five small achenes (dry, one seeded fruit) are usually produced in each flower head. These achenes are ≤2.0 mm long, obovate, and black. Four to five black wedge-shaped seeds are produced by each flower and are 2 mm long with very thin white scales. Each plant can produce up to 25,000 seeds (Kaur et al. 2014). Seeds are dispersed mainly by water currents, animals, the movement of vehicles, contamination in stock feed, grains, and on machinery, and to a lesser extent by wind.

Similar Species: Ragweed parthenium is very similar in appearance to Ambrosia psilostachya (perennial ragweed), Ambrosia artemisiifolia (common ragweed), Ambrosia confertifolora (burr ragweed), and Ambrosia tenuifolia (lacy ragweed) during the vegetative stage of growth. The distinguishing characters of Parthenium hysterophorus from all these species is that it has ribbed stems and white flower heads during the flowering stage.

Plant Biology: Ragweed parthenium is most common in the southern part of Florida (USDA-NRCS 2013) but can be found throughout the state and in other southern US states. It reproduces only by seeds. Viability of seed is 85% or higher (Navie et al. 1998). Buried seeds can remain viable for 8–10 years and have been found to persist longer than seeds on the soil surface (Bulletin OEPP/EPPO bulletin 2014). In tropical and subtropical climates, at almost any time of the year, seeds can germinate if the required soil moisture is available (Parson and Cuthbertson 1992). Flowering occurs 4–8 weeks after germination and it continues until drought or frost kills the plant (Bulletin OEPP/EPPO bulletin 2014). Two to three life cycles can be completed each year under favorable conditions in warm climates (Fatimah and Ahmad 2009).

Management

Cultural and Physical Control

Cultural control involves prevention of weed seed introduction by using proper sanitation practices by using clean liners/nursery stock, growing medium, and equipment (Stamps 2011). Handweeding and hoeing can be done before the plant produces seeds but is labor intensive if a large area is infested (Goodall et al. 2010; Tadesse et al. 2010; Tamado and Milberg 2004). Plowing and rototilling are effective methods for controlling emerged plants but will not control germinating seeds. Mowing the plants can help temporarily, but ragweed parthenium quickly regenerates itself, matures, and produces more seeds (Muniyappa et al. 1980). Use of both organic and inorganic mulches can help in controlling ragweed parthenium in nurseries and landscapes by preventing seeds from germinating.

Chemical Control

Preemergence Control

Areas heavily infested with ragweed parthenium will likely contain large amounts of seeds in the soil. Because these seeds remain viable for several years, multiple preemergence herbicide applications will be needed for long-term control (Butler 1984; Navie et al. 1998; Tamado et al. 2002). Preemergence herbicides including flumioxazin (Broadstar™, SureGuard®), oxadiazon (Ronstar®), dimethenamid-P (Tower®), indaziflam (Marengo®), pendimethalin + dimethenamid-P (FreeHand®),trifluralin + isoxaben (Snapshot®), oxyfluorfen + oryzalin (Rout®), oxyfluorfen + pendimethalin (OH2®), oxyfluorfen + prodiamine (Biathlon®), and oxyfluorfen + oxadiazon (Regal O-O™) have provided good to excellent control in research trials in Florida. Application of dithiopyr (Dimension®), pendimethalin (Pendulum®), prodiamine (Barricade®), and trifluralin (Treflan) alone provide poor control. Preemergence herbicides labeled for use in and around ornamentals for ragweed parthenium control are listed in Table 1.

Postemergence Control

Postemergence herbicides that have shown some degree of success for controlling ragweed parthenium in ornamental crop production or in landscapes include bentazon (Basagran® T&O) (Muniyappa and Krishnamurthy 1976), diquat (Reward®) (Muniyappa et al. 1980), glufosinate (Finale®) (Crane et al. 2006; Reddy et al. 2007), halosulfuron (SedgeHammer® or ProSedge) (Reddy et al. 2007), sulfosulfuron (Certainty®) (Tiwari et al. 2009), and clopyralid (Lontrel®). Better control will be achieved when plants are small and are not flowering (Stamps 2011). Postemergence herbicides labeled for use in ornamental plant production and landscapes for ragweed parthenium are listed in Table 2. Glyphosate has been shown to be effective on some ragweed parthenium biotypes (Muniyappa et al. 1980; Reddy et al. 2007; Singh et al. 2004) but provides no control of biotypes present in Florida (Odero et al. 2012). Tank-mixtures of saflufenacil (Detail®) and Tower have shown to provide excellent control of ragweed parthenium (Fernandez et al. 2015). While Tower® can be applied in and around ornamental plant production, Detail can only be applied to non-crop areas in nurseries.

References

Butler, J. 1984. “Longevity of Parthenium hysterophorus L. Seed in the Soil.” Australian Weeds 3(1): 6.

Crane, J. H., R. Stubblefield, and C. W. Meister. 2006. “Herbicide Efficacy to Control Parthenium (Parthenium hysterophorus) Under Grove Conditions in Homestead, Florida.” Proceedings of the Florida State Horticultural Society CXIX: 9–12.

European and Mediterranean Plant Protection Organization. 2014. “Parthenium hysterophorus L. Asteraceae- Parthenium weed.” Bulletin OEPP/EPPO Bulletin 44(3): 474–478.

Evans, H. 1997. “Parthenium hysterophorus: A Review of Its Weed Status and the Possibilities for Biological Control.” Biocontrol News and Information 18(3): 89N–98N.

Fatimah, H., and T. Ahmad. 2009. “Phenology of Parthenium hysterophorus—a key factor for the success of its invasion." Advances in Environmental Biology: 150–157.

Fernandez, J. V., D. C. Odero, G. E. MacDonald, J. Ferrell, and L. A. Gettys. 2015. “Confirmation, Characterization, and Management of Glyphosate-Resistant Ragweed Parthenium (Parthenium hysterophorus L.) in the Everglades Agricultural Area of South Florida." Weed Technology 29(2): 233–242.

Goodall, J., M. Braack, J. de Klerk, and C. Keen. 2010. “Study on the Early Effects of Several Weed-Control Methods on Parthenium hysterophorus L.” African Journal of Range & Forage Science 27(2): 95–99.

Kaur, M., N. K. Aggarwal, V. Kumar, and R. Dhiman. 2014. "Effects and management of Parthenium hysterophorus: A weed of global significance." International scholarly research notices.

Muniyappa, T. V., and K. Krishnamurthy. 1976. “Growth of Parthenium under Different Soil Conditions and Relative Efficacy of Pre-Emergent Herbicides.” Indian Journal of Weed Science 8(2): 115–120.

Muniyappa, T. V., T. V. Prasad, and K. Krishnamurthy. 1980. “Comparative Effectiveness and Economics of Mechanical and Chemical Methods of Control of Parthenium hysterophorus Linn.” Indian Journal of Weed Science 12(2): 137–144.

Navie, S. C., F. D. Panetta, R. E. McFadyen, and S. W. Adkins. 1998. “Behaviour of Buried and Surface-Sown Seeds of Parthenium hysterophorus.” Weed Research 38(5): 335–341.

Odero, D. C. 2012 "Response of ragweed parthenium (Parthenium hysterophorus) to saflufenacil and glyphosate." Weed Technology 26(3): 443–448.

Parsons, W. T., and E. G. Cuthbertson.1992. Noxious Weeds of Australia. Melbourne, Australia: Inkata Press.

Reddy, K. N., C. T. Bryson, and I. C. Burke. 2007. “Ragweed Parthenium (Parthenium hysterophorus) Control with Preemergence and Postemergence Herbicides.” Weed Technology 21(4): 982–986.

Rollins, R. C.1950. "The guayule rubber plant and its relatives." Contributions from the Gray Herbarium of Harvard University 172 : 1–72.

Singh, S., A. Yadav, R. S. Balyan, R. K. Malik, and M. Singh. 2004. “Control of Ragweed Parthenium (Parthenium hysterophorus) and Associated Weeds.” Weed Technology 18(3): 658–664.

Stamps, R. H. 2011. Identification, Impacts, and Control of Ragweed Parthenium (Parthenium hysterophorus L.). (ENH1187) Gainesville: University of Florida Institute of Food and Agricultural Sciences. http://edis.ifas.ufl.edu/ep448

Tadesse, B., T. K. Das, and N. T. Yaduraju. 2010. “Effects of Some Integrated Management Options on Parthenium Interference in Sorghum.” Weed Biology and Management 10(3): 160–169.

Tamado, T., and P. Milberg. 2004. “Control of Parthenium (Parthenium hysterophorus) in Grain Sorghum (Sorghum bicolor) in the Smallholder Farming System in Eastern Ethiopia.” Weed Technology 18(1): 100–105.

Tamado, T., W. Schutz, and P. Milberg. 2002. “Germination Ecology of the Weed Parthenium hysterophorus in Eastern Ethiopia.” Annals of Applied Biology 140(3): 263–270.

[USDA-NRCS] US Department of Agriculture–Natural Resources Conservation Service. 2013. “Plants Profile: Parthenium hysterophorus L.” Accessed October 12. http://plants.usda.gov/core/ profile?symbol=PAHY.

Tables

Table 1. 

Preemergence herbicides labeled for use in ornamental plant production and landscapes to control Parthenium hysterophorous (Ragweed parthenium).

Common Name

(active ingredient)

Example Trade Name and Formulation

Labeled Use Rate (Product/Acre)

WSSA Herbicide Group

Efficacy

Container Production

Field Production

Greenhouse or Fully-Enclosed Structures

Landscape

dithiopyr

Dimension® 2EW

1 to 2 pts.

3

P-S

YES

YES

NO

YES

oryzalin

Oryzalin 4 Pro

2 to 4 qt.

3

P

YES

YES

NO

YES

pendimethalin

Pendulum® 2G

100 to 200 lbs.

3

P

YES

YES

NO

YES

Pendulum® 3.3EC

2.4 to 4.8 qt.

YES

YES

NO

YES

prodiamine

RegalKade 0.5G

132 to 300 lbs.

3

P-S

YES

YES

NO

YES

Barricade® 4FL

21 to 48 fl. oz.

trifluralin

Treflan 5G

240 to 320 lbs.

3

P

YES

YES

NO

YES

flumioxazin

Broadstar™ 0.25G

150 lbs.

14

C

YES

YES

NO

YES

SureGuard® 51WDG

8 to 12 oz.

YES

YES

NO

YES

dimethenamid-p

Tower® 6EC

21 to 32 fl. oz.

15

P-S

YES

YES

NO

YES

s-metolachlor

Pennant Magnum® 7.6 EC

1.3 to 2.6 pts.

15

P-S

YES

YES

NO

YES

isoxaben

Gallery® 75DF

0.66 to 1.33 lbs.

21

C

YES

YES

NO

YES

Gallery® 4.16SC

16 to 31 fl. oz.

indaziflam

Marengo® 0.622 SC

7.5 to 15.5 fl.oz.

29

C

NO

YES

YES

NO

Marengo® 0.0224G

100 to 200 lbs.

YES

YES

NO

NO

pendimethalin + dimethenamid-p

FreeHand® 1.75G

100 to 200 lbs.

3 + 15

S

YES

YES

NO

YES

trifluralin + isoxaben

Snapshot® 2.5TG

100 to 200 lbs.

3 + 21

C

YES

YES

NO

YES

prodiamine + isoxaben

Gemini

43.5 to 87 fl.oz.

3 + 21

C

YES

YES

NO

NO

oxyfluorfen + oryzalin

Rout® 3G

100 lbs.

14 + 3

C

YES

YES

NO

YES

oxyfluorfen + pendimethalin

OH2® 3G

100 lbs.

14 + 3

C

YES

YES

NO

YES

oxyfluorfen + prodiamine

Biathlon® 2.75G

100 lbs.

14 + 3

C

YES

YES

NO

YES

oxyfluorfen + oxadiazon

Regal O-O™ 3G

100 lbs.

14 + 14

C

YES

YES

NO

YES

1Herbicide groups are based according to primary sites of action and can be used to select herbicides that have differing sites of action (Weed Technology 17:605–619 [2003]).

2P = poor control; S = suppression; C = good control

3Can only be used in selected conifer and deciduous tree species. Check manufacturer's label for a complete list of species and recommended application methods.

4Can be applied as a directed application around established woody landscape ornamentals.

5Marengo® 0.622 SC can be used in pot-in-pot container ornamentals as a directed application only.

6Labeled for use on greenhouse floors prior to plant production. Plants can be placed inside greenhouse 24 hours after application

7Indiziflam is also available by the trade name Specticle which can be applied to turf and landscape sites.

Table 2. 

Postemergence herbicides labeled for use in and around ornamentals for control of ragweed parthenium1.

Active Ingredient

Example trade name and formulation

Labeled Use Rates (product/Acre)

WSSA Herbicide Group

Container production

Field production

Greenhouse or fully-enclosed structures

Landscape

Notes

Sulfosulfuron

Certainty®

1.25 oz.

2

NO

YES

NO

YES

Use as a directed application around ornamental plants; Label includes a small list of ornamentals that can be treated over the top.

Halosulfuron

SedgeHammer®

0.66 to 1.33 oz.

2

NO

NO

NO

YES

Use as a directed application around established ornamental plantings.

Clopyralid

Lontrel® Turf & Ornamental

0.25 to 1.33 pts

4

NO

YES

NO

YES

Do not apply near desireable legumes, composites, or plants in the solanaceae (nightshade) family.

Bentazon

Basagran® T/O

24 to 32 fl. oz

6

YES

YES

NO

YES

Thorough coverage is needed; Do not apply near rhododendrons or sycamores.

Glufosinate

Finale®

2 to 6 qt.

10

YES

YES

YES

YES

Thorough coverage is needed

Diquat

Reward®

1 to 2 qt.

22

YES

YES

YES

YES

Thorough coverage and repeated applications may be needed.

1Postemergence control is highly dependant upon the growth stage at the time of application. Many factors can impact herbicide performance. Repeat applications and use of preemergence herbicides may be needed for complete control.

2Herbicide groups are based according to primary sites of action and can be used to select herbicides that have differing sites of actions (Weed Technology 17:605-619 [2003]).

Footnotes

1.

This document is ENH1270, one of a series of the Environmental Horticulture Department, UF/IFAS Extension. Original publication date July 2016. Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

Debalina Saha, graduate research assistant, Environmental Horticulture Department, Mid-Florida REC, Apopka, FL; Chris Marble, assistant professor, Environmental Horticulture Department, Mid-Florida REC, Apopka, FL; Robert H. Stamps, professor emeritus and Extension cut foliage specialist, Environmental Horticulture Department, Mid-Florida REC, Apopka, FL; and Shawn Steed, environmental horticulture production Extension agent, Seffner, FL; Nathan S. Boyd, associate professor, Horticultural Sciences Department, Gulf Coast REC, Wimauma, FL; UF/IFAS Extension.


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