Ragweed Parthenium Control Programs in South Florida
Calvin Odero
Tropical Research & Education Center
Homestead, FL
Weed Science Research at EREC
• Crops
‒ Sugarcane
‒ Vegetables
‒ Bioenergy crops
‒ Rice
South Florida Sugarcane Region
Miami
West PalmBeach
Total Sugarcane Acreage
2010-2011
389,616 acres
Organic Soils
319,553 acres82 %
Sandy Soils
70,063 acres18 %
Non-crop areas
Common ragweed
Ragweed parthenium
Ragweed parthenium
Ragweed parthenium
(Parthenium hysterophorus)
Synonyms• False ragweed• Santa Maria feverfew
Asteraceae
Native• Central America• West Indies• South America
Distribution of parthenium
Biology and life cycle
Erect-branched annual, grow, flower throughout the year in subtropical environs
Predominantly germinate in spring, early summer• Flower 4 to 8 wks after germination,1-3 ft tall
Prolific seed producer capable of producing 19,000 seeds/ft2 • Soil seedbank quantities of 4,200 seeds/ft2
Buried seeds remain viable in soil for >2 yrs • Build-up a substantial, persistent seedbank• Viable for only 6 months on surface
Seedling
Cotyledons • Rounded paddle shape, 0.1
to 0.2-in long, borne on short stalks <1-in long
1st true leaves• Egg-shaped, covered in
fine, white hairs
Older leaves • Lobed, deeply divided
Seedling • Basal rosette • Leaves 3 to 8-in long,1 to 2-
in wide• Hairy (leaves, stems)
Mature plant
Stems • Erect, hairy• Branched, covered by
longitudinal lines
Leaves • Alternate, deeply
lobed• Lower leaves form a
basal rosette, upper leaves can be entirely or slightly lobed
• Hairy
Mature plant
Flower heads • Clusters at the top of plant,
borne on short stalks, arise from the leaf forks
• Densely haired small, white, form a 5-side disk shape
• Long white flowerlets (ray flowers) present in the corners
• Flower heads become hard and brown as they mature
Seeds • < 0.1-in long, flattened,
narrow-diamond shape• Striped grey to black
Deep taproot
Negative impacts
Rapid invader that reduces biodiversity, affects landscape, soil qualityAllelopathic (parthenin)• Tree spp, crops, weed spp
Yield reduction• Sorghum (49-97%)
Harmful to humans, livestock• Contact dermatitis, skin irritation, nausea,
giddiness, respiratory problems (bronchitis, asthma)• Ingestion by livestock results in acute toxicity
Parthenium control in EAA
Frequency of detection of parthenium is on the rise in recent years in the EAA• Ditch banks, cultivated fields, noncropland
Increase can be attributed to• Repeated use of glyphosate over the years which
has imposed unprecedented selection pressure on weed populations − Shifts in weed species from those easily controlled by
glyphosate to those more tolerant − Glyphosate resistance?
• Lack of POST herbicides with residual activity
Saflufenacil
Trade name: Sharpen
Preplant, PPI, PRE burndown, POST harvest aid• Corn, small grains, fallow, legumes
Pyrimidinedione• Protoporphyrinogen-IX-oxidase (PPO)
− Chlorophyll biosynthesis
• PPO inhibition results in a rapid loss of membrane integrity− Cellular leakage, tissue necrosis, plant death
• Readily absorbed by roots, shoots, leaves− Translocated via the xylem, relatively little movement in the phloem
• Contact and residual activity− Show initial injury symptoms within a few hours
25 g ai/ha (1 fl oz/A) saflufenacil treated parthenium 1 DAT
Saflufenacil
Broad-spectrum control of broadleaf weeds• More tolerant/resistant to glyphosate
− Common lambsquarters, Russian thistle, waterhemp, common and giant ragweed
Parthenium difficult to control with glyphosate• Can saflufenacil be a control option for
parthenium in the EAA?
Objective
Compare the response of parthenium to POST application of saflufenacil in the EAA
Methods
Greenhouse experiments at EREC
CRD• Saflufenacil
− 0, 0.8, 1.6, 3.1, 6.3, 12.5, 25, 50 g ai/ha
• Glyphosate− 0, 26, 53, 105, 210, 420, 840, 1680 g ae/ha
POST application• Rosette stage of parthenium
Treatments applied with a CO2 pressurized knapsack sprayer• 8002, 180 L/ha, 276 kPa
Methods
Parthenium injury visually estimated at 7 and 14 DAT, scale of 0 to100 where 0 = no injury
100 = complete plant death
Parthenium harvested at soil level at 14 DAT to determine biomass
Parthenium survival (regrowth) following herbicide treatment recorded at 14 DAT
Methods
• Nonlinear regression performed to quantify effect of herbicide rate on − Visual injury, dry weight, survival
• drc package of R
Left to right: 0, 26, 53, 105, 210, 420, 840, 1680, 0 g ai/ha saflufenacil
treated plants at 7 DAT
Saflufenacil: Injury (7, 14 DAT)
ED90 = 18.9 g ai/ha (7 DAT) ED90 = 8.0 g ai/ha (14 DAT)
Saflufenacil: dry weight
GR90 = 8.9 g ai/ha
Saflufenacil: probability of survival
Glyphosate: dry weight
Left to right: 0, 26, 53, 105, 210, 420, 840, and 1680 g ae/ha glyphosate treated plants at 7 DAT
Field experiment
In 2010 and 2011 at the EREC, King Ranch near Belle Glade
RCBD, 4 reps• Saflufenacil (6.2, 12.5, 25, 50 g ai/ha)• Glyphosate (840, 1680 g ae/ha)
Parthenium injury visually estimated at 7, 14, 21 DAT, scale of 0 to100 where 0 = no injury
100 = complete plant death
Field: Control
ED90 = 27.0 g ai/ha (7 DAT) ED90 = 6.2 g ai/ha (14 DAT)ED90 = 5.7 g ai/ha (21 DAT)
1 DAT (12.5 g ai/ha)
7 DAT (12.5 g ai/ha)
Discussion
Parthenium control increased as rates of saflufenacil increased• Greenhouse: ED90 of 18.9 and 8.0 g ai/ha at 7 and 14 DAT
• Field: ED90 of 27.0, 6.2, and 5.7 g ai/ha at 7, 14, and 21 DAT
Parthenium dry weight decreased as rates of saflufenacil increased • GR90 of 8.9 g ai/ha
Probability of rosette ragweed survival decreased with increasing rates of saflufenacil
No response of parthenium to glyphosate even at 1680 g ae/ha (43 fl oz/A ~2.5 pt/A)
Conclusion
Saflufenacil can be applied as a POST burndown for control of parthenium
ED90 values from 14 DAT indicated that saflufenacil can provide 90% control of ragweed parthenium at 5.7 to 8.0 g ai/ha (<0.5 fl oz/A)• Lower than the saflufenacil recommended POST burn-down
− 25 to 50 g ai/ha (1 to 2 fl oz/A) for fallow areas− 2 to 4 fl oz/A (<6-in weeds) for noncropland− 4 to 6 fl oz/A (>6-in weeds) for noncropland
Saflufenacil plus other herbicides can provide residual control of parthenium and other broadleaf weeds• Eliminate the need for repeated herbicide application by
saving the grower both time and additional application cost
Other herbicides for control
PreemergenceAlachlor (Lasso)
Atrazine
Chlorimuron (Classic)
Flumioxazin (Valor)
Postemergence• 2,4-D amine• 2,4-D plus atrazine• Bentazon (Basagran)• Dicamba (Banvel)• Diquat (Reward)• Acifluorfen (Blazer) PPO soybean• Glufosinate (Liberty)• Metsulfuron (Escort)• Halosulfuron (Sandea)• Metribuzin (Dimetric)• Picloram (Tordon)• Trifloxusylfuron (Envoke)
Literature sources
EDISOdero, D.C., B. A. Sellers, and J.A. Ferrell. Biology and Control of Ragweed Parthenium in Non-Cropland.
Stamps, R. H. Identification, Impacts, and Control of Ragweed Parthenium (Parthenium hysterophorus L.)
Odero, D. C. Response of ragweed parthenium (Parthenium hysterophorus) to saflufenacil and glyphosate. Weed Technology. In press.
Contact information
Calvin Odero
Phone: 561-993-1509
Email: [email protected]
http://erec.ifas.ufl.edu/weeds/
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