Tag Archives: Weed of the Month

Weed of the Month: Velvetleaf

Originally from Asia and used as a fiber crop, velvetleaf was found in the United States around 1700. Today, velvetleaf can be found in fields as a weed and controlled by a variety of methods.

  • Common name: Velvetleaf
  • Scientific name: Abutilon theophrasti Medicus1
  • Annual or perennial: Summer annual1
  • Root system: Fibrous and taproot system2
  • Leaf arrangement: Alternate2
  • Leaf shape: Heart-shaped3
  • Flowers: Yellow with five petals3

Fast facts

  • Extreme heights: If left untouched, a velvetleaf plant can grow up to 7 feet tall.2
  • Seeds: Velvetleaf produces approximately 2,000 to 9,000 seeds per plant in capsules that contain 35 to 45 seeds.1
  • Competitiveness: If velvetleaf is left untouched, it can reduce corn yield by 20% to 34% if there are three plants per square foot.1
  • Soil Types: Velvetleaf thrives in compacted soils rich with nitrogen and with a high pH.1
  • Emergence: Velvetleaf emergences from the top 2 inches of soil. It will not survive germination if it remains on the soil surface.1

Identify differences between seedling velvetleaf, seedling prickly sida and seedling spurred anoda

  • Velvetleaf has one heart-shaped cotyledon and one round cotyledon; prickly sida has two heart-shaped cotyledons.2
  • Velvetleaf cotyledons are thicker than pricky sida cotyledons.2
  • Velvetleaf and spurred anoda both have similarly shaped cotyledons; but as the plant grows, spurred anoda’s first leaves are more triangular.2

Control tips

  • Flaming is an effective method for controlling velvetleaf.1
  • Hoeing can control velvetleaf if the plant is less than ¼ inch tall.1
  • A no-till situation can help control velvetleaf because the seed cannot survive on the surface.1
  • There are also herbicide options for velvetleaf control.1

Where Herbicide-resistant Velvetleaf Lives (according to WeedScience.org)

Corteva Agriscience offers the following weed control solutions:

Corn Herbicides

DuPont Cinch® ATZ herbicide
Durango® DMA® herbicide
Elevore® herbicide
Enlist Duo® herbicide, as part of the Enlist weed control system
Enlist One® herbicide, as part of the Enlist weed control system
FulTime® NXT herbicide
Keystone® LA NXT herbicide
Keystone® NXT herbicide
DuPont Realm® Q herbicide
Resicore® herbicide
SureStart® II herbicide

Soybean Herbicides
Durango® DMA® herbicide
Elevore herbicide
Enlist Duo® herbicide, as part of the Enlist weed control system
Enlist One® herbicide, as part of the Enlist weed control system
DuPont EverpreX® herbicide
FirstRate® herbicide
Sonic® herbicide
Surveil® herbicide
DuPont Trivence® herbicide
DuPontEnlite® herbicide
DuPontAfforia® herbicide
DuPont™ FeXapan™ herbicide Plus VaporGrip® Technology


Sources:

1Michigan State University, Department of Plant, Soil and Microbial Sciences. Velvetleaf. https://www.canr.msu.edu/weeds/extension/velvetleaf
2Steckel, L. Velvetleaf. https://extension.tennessee.edu/publications/Documents/W167.pdf
3University of Massachusetts Extension. Abutilon theophrasti. https://extension.umass.edu/landscape/weeds/abutilon-theophrasti

™®Afforia, Cinch, DMA, DuPont, Durango, Elevore, Enlist, Enlist Duo, Enlist One, Enlite, EverpreX, FeXapan, FirstRate, FulTime, Keystone, Realm, Resicore, Sonic, SureStart, Surveil and Trivence are trademarks of Dow AgroSciences, DuPont or Pioneer, and their affiliated companies or their respective owners. VaporGrip® is a registered trademark of the Bayer Group. Cinch ATZ, FeXapan herbicide Plus VaporGrip Technology, FulTime NXT, Keystone LA NXT and Keystone NXT are Restricted Use Pesticides. Cinch ATZ, Durango DMA, Elevore, FeXapan herbicide Plus VaporGrip Technology, FulTime NXT, Keystone LA NXT, Realm Q, Resicore, Sonic, SureStart II and Surveil are not registered for sale or use in all states. Keystone NXT is not available for sale, distribution or use in all states. FulTime NXT, Keystone LA NXT, Keystone NXT, Resicore and SureStart II are not available for sale, distribution or use in Nassau and Suffolk counties in the state of New York. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. EverpreX is not registered in all states. See your Corteva Agriscience retailer or representative for availability in your state. Enlist Duo and Enlist One herbicides are not registered for sale or use in all states or counties. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your area. Enlist Duo and Enlist One herbicides are the only 2,4-D products authorized for use in Enlist crops. Consult Enlist herbicide labels for weed species controlled. Always read and follow label directions. © 2019 Corteva.

Weed of the Month: Purple Deadnettle

You may spy the color purple in the field and wonder what weed it is. While purple deadnettle looks similar to its relative henbit, they have various distinctive characteristics. Read below to learn how to identify and control purple deadnettle.

  • Common name: Purple deadnettle
  • Scientific name: Lamium purpureum1
  • Annual or perennial: winter annual2
  • Leaf arrangement: opposite2
  • Leaf venation: palmate2
  • Leaf width: ½ to 1 inch2
  • Leaf shape: triangular to heart-shaped3
  • Root type: fibrous2

Fast facts

  • Life cycle: Since purple deadnettle is a winter annual, it will grow best in the spring. It dies during the warmer summer months and will germinate again the fall. The weed remains dormant through the winter and grows well if warm weather is present.2
  • Reproduction: Purple deadnettle produces flowers in the spring that are blue and/or purple in color.2
  • Seeds: Approximately 27,000 seeds are produced per plant in areas without competition. The seeds then germinate in the early fall.1
  • Soil types: Purple deadnettle thrives in nutrient-rich soils. For example, you could find it in humic, loamy or sandy-loamy soils.1

Spot the differences between purple deadnettle and henbit

  • Purple deadnettle can reach heights of 16 to 18 inches tall; henbit can grow up to 15 inches tall.3
  • Both species have oval-shaped cotyledons; however, in henbit, the hypocotyl is green and turns purple as it grows.3
  • Henbit has hairs on the top of leaves, while purple deadnettle does not.3
  • The upper leaves of purple deadnettle are purple/red in color, while the lower leaves are a deep green. All leaves on henbit are green.3
  • Henbit has a square-shaped stem, while purple deadnettle does not.3

Control tips

  • Control is most effective in the fall, when the plants are germinating and young.1
  • Tillage is an easy way to control deadnettle when done in the spring.1
  • Many herbicides are effective when applied in the fall or early spring.1
  • If you are planting small grains, alfalfa or crops in a no-tillage system, deadnettle may compete for resources. Plant these crops at high rates to suppress its growth.1

Corteva Agriscience offers the following weed control solutions:

Corn Herbicides

DuPont Cinch® ATZ herbicide
Durango® DMA® herbicide
Elevore® herbicide
Enlist Duo® herbicide, as part of the Enlist weed control system
Enlist One® herbicide, as part of the Enlist weed control system
FulTime® NXT herbicide
Keystone® LA NXT herbicide
Keystone® NXT herbicide
DuPont Realm® Q herbicide
Resicore® herbicide
SureStart® II herbicide

Soybean Herbicides
Durango® DMA® herbicide
Elevore herbicide
Enlist Duo® herbicide, as part of the Enlist weed control system
Enlist One® herbicide, as part of the Enlist weed control system
DuPont EverpreX® herbicide
FirstRate® herbicide
Sonic® herbicide
Surveil® herbicide
DuPont Trivence® herbicide
DuPontEnlite® herbicide
DuPontAfforia® herbicide
DuPont™ FeXapan™ herbicide Plus VaporGrip® Technology


Sources:

1Michigan State University, Department of Plant, Soil and Microbial Sciences. Purple deadnettle. https://www.canr.msu.edu/weeds/extension/purple-dead­nettle
2Peacock, C. Purple Deadnettle. https://www.turffiles.ncsu.edu/weeds-in-turf/purple-deadnettle/
3Steckel, L. Purple Deadnettle and Henbit. https://extension.tennessee.edu/publications/Documents/W165.pdf

Additional Resource:

University of Missouri, Division of Plant Sciences. 2018. Purple Deadnettle. https://weedid.missouri.edu/weedinfo.cfm?weed_id=153

Afforia, Cinch, DMA, DuPont, Durango, Elevore, Enlist, Enlist Duo, Enlist One, Enlite, EverpreX, FeXapan, FirstRate, FulTime, Keystone, Realm, Resicore, Sonic, SureStart, Surveil and Trivence are trademarks of Dow AgroSciences, DuPont or Pioneer, and their affiliated companies or their respective owners. VaporGrip® is a registered trademark of the Bayer Group. Cinch ATZ, FeXapan herbicide Plus VaporGrip Technology, FulTime NXT, Keystone LA NXT and Keystone NXT are Restricted Use Pesticides. Cinch ATZ, Durango DMA, Elevore, FeXapan herbicide Plus VaporGrip Technology, FulTime NXT, Keystone LA NXT, Realm Q, Resicore, Sonic, SureStart II and Surveil are not registered for sale or use in all states. Keystone NXT is not available for sale, distribution or use in all states. FulTime NXT, Keystone LA NXT, Keystone NXT, Resicore and SureStart II are not available for sale, distribution or use in Nassau and Suffolk counties in the state of New York. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. EverpreX is not registered in all states. See your Corteva Agriscience retailer or representative for availability in your state. Enlist Duo and Enlist One herbicides are not registered for sale or use in all states or counties. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your area. Enlist Duo and Enlist One herbicides are the only 2,4-D products authorized for use in Enlist crops. Consult Enlist herbicide labels for weed species controlled. Always read and follow label directions. © 2019 Corteva.

FeXapan® herbicide Plus VaporGrip® Technology is a Restricted Use Pesticide. For retail sale to and use only by Certified Applicators and only for those uses covered by the Certified Applicator’s certification. FeXapan herbicide Plus VaporGrip Technology is not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Always read and follow label directions. VaporGrip Technology is a registered trademarks of Monsanto Technology LLC used under license.

Weed of the Month: Palmer Amaranth

Palmer amaranth of the pigweed group is becoming more invasive to the Midwest and causing agronomic issues. With its resistance to glyphosate and other ALS herbicides, this weed has an adaptable nature that continues to challenge farmers across the country.

Palmer Amaranth

  • Common name: Palmer Amaranth
  • Scientific name: Amaranthus palmeri1
  • Have a small hair in leaf tip notch1
  • Long petioles connect the leaf to the main stem1

Fast facts

  • Genetic diversity: Palmer amaranth is a dioecious species, which means that there are separate male and female plants. Dioecious species can increase genetic diversity, making it difficult to control.1
  • Many seeds: Each Palmer amaranth plant can produce at least 100,000 seeds in crop fields and up to a half-million seeds in undisturbed land.1
  • Undisturbed soil: Palmer amaranth thrives in no-till or minimum-till fields because it can emerge from the top few inches of soil.1
  • Extended emergence period: Palmer amaranth must be managed throughout the entire growing season due to its ability to emerge from early May to mid-September.1

Resistance statistics*

  • According to WeedScience.org, herbicide-resistant Palmer amaranth has been discovered in 28 states:* Alabama, Arizona, Arkansas, California, Delaware, Florida, Georgia, Illinois, Indiana, Kansas, Kentucky, Louisiana, Maryland, Michigan, Mississippi, Missouri, Nebraska, New Jersey, New Mexico, North Carolina, Ohio, Oklahoma, Pennsylvania, South Carolina, Tennessee, Texas, Virginia and Wisconsin.
  • Palmer amaranth has developed resistance against numerous herbicide modes of action, including the following: ALS inhibitors (Group 2), dinitroanilines (Group 3), triazines (Group 5), HPPD inhibitors (Group 27), PPO inhibitors (Group 14), long chain fatty acid inhibitors (Group 15), and glyphosate (Group 9).1

*Resistance confirmation does not include all weeds and may vary among different areas of each state.

Identify the differences between common waterhemp and Palmer amaranth

  • Cotyledons of Palmer amaranth are long and narrow, while the cotyledons of waterhemp are not as elongated.2
  • True leaves (the leaves that follow cotyledon leaves) have a small notch, sometimes with a hair, in the tip.2
  • Early identification can allow for early herbicide usage to best control these weeds.2

Corteva Agriscience offers the following weed control solutions:

Corn Herbicides

DuPont Cinch® ATZ herbicide
Durango® DMA® herbicide
Elevore® herbicide
Enlist Duo® herbicide, as part of the Enlist weed control system
Enlist One® herbicide, as part of the Enlist weed control system
FulTime® NXT herbicide
Keystone® LA NXT herbicide
Keystone® NXT herbicide
DuPont Realm® Q herbicide
Resicore® herbicide
SureStart® II herbicide

Soybean Herbicides
Durango® DMA® herbicide
Elevore herbicide
Enlist Duo® herbicide, as part of the Enlist weed control system
Enlist One® herbicide, as part of the Enlist weed control system
DuPont EverpreX® herbicide
FirstRate® herbicide
Sonic® herbicide
Surveil® herbicide
DuPont Trivence® herbicide
DuPontEnlite® herbicide
DuPontAfforia® herbicide
DuPont™ FeXapan™ herbicide Plus VaporGrip® Technology


Sources:

1Legleiter, T., and B. Johnson. 2013. Palmer Amaranth Biology, Identification, and Management. https://www.extension.purdue.edu/extmedia/WS/WS-51-W.pdf
2Jhala, A., 2017. How to Differentiate Common Waterhemp and Palmer Amaranth Seedlings. https://cropwatch.unl.edu/2017/how-differentiate-common-waterhemp-and-palmer-amaranth-seedlings

Afforia, Cinch, DMA, DuPont, Durango, Elevore, Enlist, Enlist Duo, Enlist One, Enlite, EverpreX, FeXapan, FirstRate, FulTime, Keystone, Realm, Resicore, Sonic, SureStart, Surveil and Trivence are trademarks of Dow AgroSciences, DuPont or Pioneer, and their affiliated companies or their respective owners. VaporGrip® is a registered trademark of the Bayer Group. Cinch ATZ, FeXapan herbicide Plus VaporGrip Technology, FulTime NXT, Keystone LA NXT and Keystone NXT are Restricted Use Pesticides. Cinch ATZ, Durango DMA, Elevore, FeXapan herbicide Plus VaporGrip Technology, FulTime NXT, Keystone LA NXT, Realm Q, Resicore, Sonic, SureStart II and Surveil are not registered for sale or use in all states. Keystone NXT is not available for sale, distribution or use in all states. FulTime NXT, Keystone LA NXT, Keystone NXT, Resicore and SureStart II are not available for sale, distribution or use in Nassau and Suffolk counties in the state of New York. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. EverpreX is not registered in all states. See your Corteva Agriscience retailer or representative for availability in your state. Enlist Duo and Enlist One herbicides are not registered for sale or use in all states or counties. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your area. Enlist Duo and Enlist One herbicides are the only 2,4-D products authorized for use in Enlist crops. Consult Enlist herbicide labels for weed species controlled. Always read and follow label directions. ©2019 Corteva

FeXapan® herbicide Plus VaporGrip® Technology is a Restricted Use Pesticide. For retail sale to and use only by Certified Applicators and only for those uses covered by the Certified Applicator’s certification. FeXapan herbicide Plus VaporGrip Technology is not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Always read and follow label directions. VaporGrip Technology is a registered trademarks of Monsanto Technology LLC used under license.

Weed of the Month: Cocklebur

  • Common name: Common cocklebur
  • Scientific name: Xanthium strumarium1
  • Life cycle: Summer annual1
  • Seedlings: Stem is purple in color with large cotyledons.
  • Leaf arrangement: Early leaves are arranged in an opposite pattern; mature leaves are arranged in an alternate pattern.

Fast facts

  • Common cocklebur can grow between 2 to 4 feet tall.2
  • Common cocklebur can be found in agricultural fields, on roadsides, in ditches, in pastures, in orchards and in unmanaged places.2
  • Each bur contains two seeds — with one larger than the other.1
  • Cocklebur seeds and seedlings can be fatal to livestock if the animal ingests 1% or more of its body weight.2
  • Mature plants have thick stems with purple or black spots.2
  • The leaves of the mature plant have a distinct scent.2
  • Male flowers are red and form in clusters with female flowers below on the stalk. Cocklebur flowers during the months of July to October.2
  • The cocklebur seeds are brown, egg-shaped and prickly.1

Resistance statistics*

  • According to WeedScience.org, herbicide-resistant common cocklebur has been discovered in 15 states:* Alabama, Arkansas, Illinois, Iowa, Kansas, Louisiana, Maryland, Minnesota, Mississippi, Missouri, North Carolina, Ohio, Oklahoma, South Carolina and Tennessee.

*Resistance confirmation does not include all weeds and may vary among different areas of each state.

Corteva Agriscience, Agriculture Division of DowDuPont, offers the following weed control solutions:

Corn Herbicides

DuPont Cinch® ATZ herbicide
DuPont Realm® Q herbicide
Durango® DMA® herbicide
Elevore® herbicide
Enlist Duo® herbicide, as part of the Enlist weed control system
Enlist One® herbicide, as part of the Enlist weed control system
FulTime® NXT herbicide
Keystone® LA NXT herbicide
Keystone® NXT herbicide
Resicore® herbicide
SureStart® II herbicide

Soybean Herbicides
Durango® DMA® herbicide
DuPont EverpreX® herbicide
Elevore herbicide
Enlist Duo® herbicide, as part of the Enlist weed control system
Enlist One® herbicide, as part of the Enlist weed control system
FirstRate® herbicide
Sonic® herbicide
Surveil® herbicide
DuPontAfforia® herbicide
DuPontEnlite® herbicide
DuPont™ FeXapan™ herbicide Plus VaporGrip® Technology
DuPont Trivence® herbicide


Sources:

1University of Illinois Extension and Outreach, Department of Crop Sciences. 2019. Common Cocklebur. http://extension.cropsciences.illinois.edu/fieldcrops/weeds/common_cocklebur/
2University of California Agriculture and Natural Resources, Statewide Integrated Pest Management. 2019. Common Cocklebur. http://ipm.ucanr.edu/PMG/WEEDS/common_cocklebur.html

Additional Resource:

University of Missouri Division of Plant Sciences, Weed ID Guide. 2018. Common Cocklebur: Xanthium strumarium.https://weedid.missouri.edu/weedinfo.cfm?weed_id=314

Corteva Agriscience, the Corteva Agriscience Logo, Afforia, Cinch, DMA, DuPont, Durango, Elevore, Enlist, Enlist Duo, Enlist One, Enlite, EverpreX, FeXapan, FirstRate, FulTime, Keystone, Realm, Resicore, Sonic, SureStart, Surveil and Trivence are trademarks of Dow AgroSciences, DuPont or Pioneer, and their affiliated companies or their respective owners. VaporGrip® is a registered trademark of the Bayer Group. Cinch ATZ, FeXapan, FulTime NXT, Keystone LA NXT and Keystone NXT are Restricted Use Pesticides. Durango DMA, Elevore, FeXapan, FulTime NXT, Keystone LA NXT, Resicore, Sonic, SureStart II and Surveil are not registered for sale or use in all states. Keystone NXT is not available for sale, distribution or use in all states. FulTime NXT, Keystone LA NXT, Keystone NXT, Resicore and SureStart II are not available for sale, distribution or use in Nassau and Suffolk counties in the state of New York. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. EverpreX is not registered in all states. See your DuPont retailer or representative for availability in your state. Enlist Duo and Enlist One herbicides are not registered for sale or use in all states or counties. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your area. Enlist Duo and Enlist One herbicides are the only 2,4-D products authorized for use in Enlist crops. Consult Enlist herbicide labels for weed species controlled. Always read and follow label directions. ©2019 Dow AgroSciences LLC

Weed of the Month: Common Lambsquarters

  • Common LambsquartersCommon name: Common lambsquarters
  • Scientific name: Chenopodium album1
  • Grass or broadleaf: Summer annual broadleaf1
  • Germination timing: Common lambsquarters emerges early in the growing season, so it is key to control this weed with a postemergence herbicide prior to reaching maximum control heights.1
  • The seeds of common lambsquarters can remain dormant for many years. Fifty percent of seeds have been found to survive for 12 years, 32 percent have been found to survive for 20 years and one percent of seeds has been found to last 78 years.1
  • The cotyledons and early leaves appear blue-green on the top and a purple-red on the underside of the leaf.2

Fast facts

  • Common lambsquarters can grow up to five feet tall.2
  • Night tilling, also known as dark tillage, will reduce the emergence by 30 percent to 70 percent.1
  • Including small grains into crop rotation can suppress the growth of lambsquarters.1
  • Mature common lambsquarters’ leaves are pale green, triangular and up to 2 inches in length.2
  • The new leaves on common lambsquarters can be identified by their white, waxy coating.2
  • Common lambsquarters can produce 30,000-176,000 seeds per plant.1
  • The flowers of the common lambsquarters bloom from May to November.2

Resistance statistics*

  • According to WeedScience.org, herbicide-resistant common lambsquarters (mostly to PSII (WSSA Group 5) inhibitors) has been discovered in 22 states:* Connecticut, Delaware, Illinois, Indiana, Iowa, Maine, Maryland, Massachusetts, Michigan, Minnesota, New Hampshire, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, Tennessee, Vermont, Virginia, Washington, West Virginia and Wisconsin.

*Resistance confirmation does not include all weeds and may vary among different areas of each state.

Corteva Agriscience, Agriculture Division of DowDuPont, offers the following weed control solutions:

Corn Herbicides

DuPont Cinch® ATZ herbicide
Durango® DMA® herbicide
Elevore® herbicide
Enlist Duo® herbicide, as part of the Enlist weed control system
Enlist One herbicide, as part of the Enlist weed control system
FulTime® NXT herbicide
Keystone® LA NXT herbicide
Keystone® NXT herbicide
DuPont Realm® Q herbicide
Resicore® herbicide
SureStart® II herbicide

Soybean Herbicides
Durango® DMA® herbicide
Elevore herbicide
Enlist Duo® herbicide, as part of the Enlist weed control system
Enlist One herbicide, as part of the Enlist weed control system
DuPont EverpreX® herbicide
FirstRate® herbicide
Sonic® herbicide
Surveil® herbicide
DuPont Trivence® herbicide
DuPontEnlite® herbicide
DuPontAfforia® herbicide
DuPont™ FeXapan™ herbicide Plus VaporGrip® Technology


Sources:

1Michigan State University, Department of Plant, Soil and Microbial Sciences 2019. Common Lambsquarters. https://www.canr.msu.edu/weeds/extension/common-lambsquarters
2University of California Integrated Pest Management 2019. Common lambsquarters.  http://ipm.ucanr.edu/PMG/WEEDS/lambsquarters.html

®™Trademarks of Dow AgroSciences, DuPont or Pioneer, and their affiliated companies or their respective owners. Cinch ATZ, FeXapan, FulTime NXT, Keystone LA NXT and Keystone NXT are federally Restricted Use Pesticides. Cinch ATZ, Durango DMA, Elevore, FulTime NXT, Keystone LA NXT, Realm, Resicore, Sonic, SureStart II, Surveil and Trivence are not registered for sale or use in all states. Keystone NXT is not available for sale, distribution or use in all states. FulTime NXT, Keystone LA NXT, Keystone NXT, Resicore and SureStart II are not available for sale, distribution or use in Nassau and Suffolk counties in the state of New York. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. DuPont™ FeXapan® herbicide Plus VaporGrip® Technology is not registered for sale in all states. Contact your local DuPont retailer or representative for details and availability in your state. EverpreX is not registered in all states. See your DuPont retailer or representative for availability in your state. Enlist Duo and Enlist One herbicides are not registered for sale or use in all states or counties. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your area. Enlist Duo and Enlist One herbicides are the only 2,4-D products authorized for use in Enlist crops. Consult Enlist herbicide labels for weed species controlled. Always read and follow label directions. ©2019 Dow AgroSciences LLC

Weed of the Month: Marestail

  • marestailCommon name: Marestail, horseweed, Canada fleabane
  • Scientific name: Conyza canadensis 1
  • Grass or broadleaf: Annual broadleaf
  • Germination timing: Marestail can begin its growing season in fall or spring. Plants that emerge in the fall can survive the winter and continue growing as the row crop emerges.2
  • Marestail begins its growth cycle as a small rosette between one to four inches across. While scouting, it is important to look beneath debris because the plants may otherwise remain hidden.3
  • Many states in the Midwest are fighting the ever-growing population of marestail that is resistant to glyphosate and ALS-inhibiting herbicides.3

Fast facts

  • Marestail can grow up to six feet tall. Once a plant grows up to five inches, control becomes much more difficult.2
  • Each plant can produce 200,000 seeds per plant—which are spread primarily by wind—that can travel to neighboring farms and even nearby states.2
  • According to WeedScience.org, the first confirmation of glyphosate-resistant horseweed was in Delaware in 2000. Since then, resistance has spread across the Midwestern states.
  • Corn and small grains can help control marestail. The canopy of corn can suppress growth, while small grains can be highly competitive. 2

Weed management tips

  • Use a herbicide in the fall: an application of a burndown herbicide in the fall season can aid in marestail control. It is best to apply the herbicide with temperatures above 50 degrees and with low wind.1
  • Scout your fields: By checking the fields before or immediately after harvest, farmers can make plans to control marestail with a fall or spring herbicide.1
  • Plant a cereal rye cover crop: This crop can provide a mulch that will suppress marestail emergence.1
  • Apply a herbicide in the spring: This practice can control weeds that have grown throughout the winter and suppress emergence of any new weeds. Use a burndown herbicide mixed with a residual herbicide for best results.3

Resistance statistics*

  • According to WeedScience.org, herbicide-resistant marestail has been documented in almond, blueberry, corn, cotton, grapes, rice, soybean and wheat production in 25 states: Alabama, Arkansas, California, Delaware, Illinois, Indiana, Iowa, Kansas, Kentucky, Maryland, Michigan, Mississippi, Missouri, Montana, Nebraska, New Jersey, North Carolina, Ohio, Oklahoma, Pennsylvania, South Dakota, Tennessee, Virginia, Wisconsin and West Virginia.

*Resistance confirmation does not include all weeds and may vary among different areas of each state.

Corteva Agriscience, Agriculture Division of DowDuPont, offers the following weed control solutions:

Corn Herbicides

DuPont Cinch® ATZ herbicide
Durango® DMA® herbicide
Elevore® herbicide
Enlist Duo® herbicide, as part of the Enlist weed control system
Enlist One herbicide, as part of the Enlist weed control system
FulTime® NXT herbicide
Keystone® LA NXT herbicide
Keystone® NXT herbicide
DuPont Realm® Q herbicide
Resicore® herbicide
SureStart® II herbicide

Soybean Herbicides
Durango® DMA® herbicide
Elevore herbicide
Enlist Duo® herbicide, as part of the Enlist weed control system
Enlist One herbicide, as part of the Enlist weed control system
DuPont EverpreX® herbicide
FirstRate® herbicide
Sonic® herbicide
Surveil® herbicide
DuPont Trivence® herbicide
DuPontEnlite® herbicide
DuPontAfforia® herbicide
DuPont™ FeXapan™ herbicide Plus VaporGrip® Technology


Sources:

1Integrated Crop Management News and Iowa State University Extension and Outreach 2017. Fall Marestail (Horseweed) Management. https://crops.extension.iastate.edu/cropnews/2017/10/fall-marestail-horseweed-management
2 Penn State Extension 2017. Marestail (Horseweed) Management. https://extension.psu.edu/marestail-horseweed-management
3Nebraska Institute of Agriculture and Natural Resources 2016. Fall is Optimal for Marestail Management. https://cropwatch.unl.edu/2016/fall-optimal-marestail-management

 

®™℠Trademarks and service marks of Dow AgroSciences, DuPont or Pioneer, and their affiliated companies or their respective owners. Cinch ATZ, FeXapan Plus VaporGrip Technology and Keystone LA NXT are Restricted Use Pesticides. Durango DMA, Elevore, EverpreX, FulTime NXT, Keystone NXT, Realm, Resicore, Sonic, SureStart II, Surveil and Trivence are not registered for sale or use in all states. FulTime NXT, Keystone LA NXT, Keystone NXT, Resicore and SureStart II are not available for sale, distribution or use in Nassau and Suffolk counties in the state of New York. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Enlist Duo and Enlist One herbicides are not registered for sale or use in all states or counties. Enlist Duo and Enlist One herbicides are the only 2,4-D products authorized for use in Enlist crops. DuPont™ FeXapan™ herbicide plus VaporGrip® Technology is a Restricted Use Pesticides. DuPont™ FeXapan™ herbicide plus VaporGrip® Technology is not registered for sale or use in all states. IT IS A VIOLATION OF FEDERAL AND STATE LAW TO MAKE AN IN-CROP APPLICATION OF ANY DICAMBA HERBICIDE PRODUCT ON SOYBEANS WITH Roundup Ready 2 Xtend® technology, OR ANY OTHER PESTICIDE APPLICATION, UNLESS THE PRODUCT LABELING SPECIFICALLY AUTHORIZES THE USE. Contact the U.S. EPA and your state pesticide regulatory agency with any questions about the approval status of dicamba herbicide products for in-crop use with soybeans with Roundup Ready 2 Xtend® technology and follow all pesticide product labeling. Soybeans with Roundup Ready 2 Xtend® technology contain genes that confer tolerance to glyphosate and dicamba. Glyphosate herbicides will kill crops that are not tolerant to glyphosate. Dicamba will kill crops that are not tolerant to dicamba. Roundup Xtend®, VaporGrip®, Roundup Ready 2 Xtend® (Monsanto). VaporGrip® Technology is used under license from Monsanto Technology LLC. Always read and follow label directions. ©2019 Dow AgroSciences LLC

Weed of the Month: Giant Ragweed

  • giant ragweedCommon name: Giant ragweed
  • Scientific name: Ambrosia trifida1
  • Grass or broadleaf: Annual broadleaf
  • Giant ragweed grows in the Midwest and Eastern regions of the United States, but it is most heavily concentrated in the eastern Corn Belt states like Indiana and Illinois.2
  • Germination timing: Giant ragweed is traditionally an early season weed; however, its growing season is expanding. Giant ragweed typically sprouts in early May but has been seen as early as March. The weed can continue to cause issues through late July and can impede harvest if not controlled.2
  • Competitiveness: Giant ragweed is one of the most competitive weeds in corn and soybeans.
    • Two giant ragweed plants within a 110 square feet area can reduce corn yield by 13 percent.2
    • Soybean yield can be reduced by 50 percent when there is just one giant ragweed plant within a 110 square foot area.2
  • Giant ragweed can grow 1-5 feet taller than competing plants and can reach heights of up to 17 feet tall.2

Fast facts

  • When a giant ragweed plant first emerges, it can be identified by its spatulate cotyledons. These cotyledons are spoon-shaped and can range from 1 to 1 ¾ inches long.2
  • Giant ragweed always has three distinct lobes but can show up to five lobes that grow in an opposite arrangement.2
  • According to WeedScience.org, the first confirmation of herbicide resistant giant ragweed in the United States was in an Indiana soybean field in 1998.
  • Giant ragweed is a monoecious plant, which means that separate male and female flowers can found on a single plant.2
  • Giant ragweed seeds can be identified by their points and ridges that make them look like small crowns.2

Weed management tips2

  • Use multiple modes of action:
    • One of the best ways to fight giant ragweed is to use multiple modes of action in a herbicide program with both preemergence and postemergence herbicides.
  • Scout for weeds:
    • Look for giant ragweed two weeks after the postemergence herbicide application and determine if another application is needed.

Resistance Statistics*

  • According to to WeedScience.org, herbicide-resistant giant ragweed has been documented in corn and soybean fields in 13 states: Arkansas, Illinois, Indiana, Iowa, Kansas, Kentucky, Minnesota, Mississippi, Missouri, Nebraska, Ohio, Tennessee and Wisconsin.*

*Resistance confirmation does not include all weeds and may vary among different areas of each state.

Here are a few of the weed control solutions from Corteva Agriscience, Agriculture Division of DowDuPont:

Corn

DuPont Cinch® ATZ herbicide
Durango® DMA® herbicide
Elevore® herbicide
Enlist Duo® herbicide, as part of the Enlist weed control system
Enlist One herbicide, as part of the Enlist weed control system
Keystone® NXT herbicide
DuPont Realm® Q herbicide
Resicore® herbicide
SureStart® II herbicide
FulTime herbicide

Soybean

Durango® DMA® herbicide
Enlist Duo® herbicide, as part of the Enlist weed control system
Enlist One herbicide, as part of the Enlist weed control system
FirstRate® herbicide
Sonic® herbicide
DuPont Trivence® herbicide
DuPontEnlite® herbicide
DuPontAfforia® herbicide
DuPont™ FeXapan™ herbicide Plus VaporGrip® Technology

Additional information:

For more information, read these weed science resources:

Sources:
1University of Missouri Division of Plant Sciences 2018. Weed ID Guide, Giant Ragweed. https://weedid.missouri.edu/weedinfo.cfm?weed_id=18
2 University of Missouri 2014. Biology and Management of Giant Ragweed. https://weedscience.missouri.edu/publications/gwc-12.pdf

®™Trademark of The Dow Chemical Company (“Dow”) or E. I. du Pont de Nemours and Company (“DuPont”) or affiliated companies of Dow or DuPont. Cinch ATZ, FeXapan Plus VaporGrip Technology and Keystone NXT are federally Restricted Use Pesticides. Durango DMA, Elevore, EverpreX, FulTime NXT, Keystone NXT, Realm, Resicore, Sonic, SureStart II, Surveil and Trivence are not registered for sale or use in all states. FulTime NXT, Keystone LA NXT, Keystone NXT, Resicore and SureStart II are not available for sale, distribution or use in Nassau and Suffolk counties in the state of New York. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Enlist Duo and Enlist One herbicides are not registered for sale or use in all states or counties. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your area. Enlist Duo and Enlist One herbicides are the only 2,4-D products authorized for use in Enlist crops. DuPont™ FeXapan™ herbicide plus VaporGrip® Technology is a restricted-use pesticide. DuPont™ FeXapan™ herbicide plus VaporGrip® Technology is not registered for sale or use in all states. Contact your DuPont retailer or representative for details and availability in your state. IT IS A VIOLATION OF FEDERAL AND STATE LAW TO MAKE AN IN-CROP APPLICATION OF ANY DICAMBA HERBICIDE PRODUCT ON SOYBEANS WITH Roundup Ready 2 Xtend® technology, OR ANY OTHER PESTICIDE APPLICATION, UNLESS THE PRODUCT LABELING SPECIFICALLY AUTHORIZES THE USE. Contact the U.S. EPA and your state pesticide regulatory agency with any questions about the approval status of dicamba herbicide products for in-crop use with soybeans with Roundup Ready 2 Xtend® technology and follow all pesticide product labeling. Soybeans with Roundup Ready 2 Xtend® technology contain genes that confer tolerance to glyphosate and dicamba. Glyphosate herbicides will kill crops that are not tolerant to glyphosate. Dicamba will kill crops that are not tolerant to dicamba. Roundup Xtend® , VaporGrip® , Roundup Ready 2 Xtend® (Monsanto). VaporGrip® Technology is used under license from Monsanto Technology LLC. Always read and follow label directions. ©2018 Dow AgroSciences LLC