Early Identification Of Palmer Amaranth Essential In Reducing Yield Loss

Is it waterhemp or Palmer amaranth? Though identification can be difficult, University of Illinois associate professor of weed science Aaron Hager said early and accurate identification of Palmer amaranth plants coupled with implementation of an integrated management program are essential to reduce the potential for crop yield loss due to interference of this broadleaf weed.

Accurate identification of weedy Amaranthus species during early vegetative stages can be difficult because many look very much alike, Hager explained. “During the 1990s, waterhemp provided an excellent example of how difficult it can be to differentiate among the various Amaranthus species, especially when plants are small,” he added.

To assist weed management practitioners in accurately identifying Palmer amaranth, Hager said researchers in the U of I crop sciences department will accept tissue samples from suspected Palmer amaranth plants and use tools of molecular biology to identify whether the sample is Palmer amaranth or another species of Amaranthus. Information on how to collect and submit tissue samples from suspected Palmer amaranth plants is described on the Palmer amaranth identification form, found here. Download the form, provide as much information as possible and submit it along with the tissue samples to the address listed at the top of the form.

“Proper management of Palmer amaranth populations can help reduce the potential for seed production that will augment the soil seedbank and perpetuate the population in future growing seasons,” he said.

Palmer amaranth (Amaranthus palmeri) is a summer annual broadleaf weed species taxonomically related to other pigweed species (waterhemp, smooth, redroot) common in Illinois agronomic cropping systems. Hager said Palmer amaranth is not indigenous to Illinois, but rather it evolved as a desert-dwelling species in the southwestern United States, including areas of the Sonoran Desert. “Genotypic and phenotypic adaptability have allowed Palmer amaranth to expand its distribution and colonize the vastly different agricultural landscapes across much of the eastern half of the United States, including Illinois,” he explained.

Research has demonstrated that Palmer amaranth has a higher growth rate and is more competitive than other pigweed species. “Growth rates approaching 3 inches per day and yield losses of 78% (soybean) and 91% (corn) attributed to Palmer amaranth interference have been reported in the scientific literature,” Hager said. “Seed production capability of female Palmer amaranth plants is similar to that of female waterhemp plants.”

Hager described the cotyledon leaves of Palmer amaranth as being relatively long compared with other Amaranthus species. “Like all weedy Amaranthus species in Illinois, the true leaves — those produced after the cotyledon leaves — of Palmer amaranth have a small notch in the tip. Occasionally, a single hair can be found in the leaf notch. This hair may not be present in each leaf notch of a Palmer amaranth plant, and tends to be less common on leaves of waterhemp plants. The stems and leaves have no or few hairs and the stems feel smooth to the touch. Leaves are alternate on the stem and are generally lance-shaped or egg-shaped with prominent white veins on the underside,” he said. “As plants become older, they often assume a poinsettia-like appearance and sometimes have a white or purple chevron on the leaves. Leaves are attached to the stem by petioles that are usually longer than the leaf blade.”

Leave a Reply

Herbicides Stories

HerbicidesScouting Key To Next Season’s Soybean Herbicide Program
August 12, 2014
When growing soybeans, growers need to think ahead to stay one step ahead of weeds. That means examining weed threats and evaluating which herbicides work best. Read More
HerbicidesArysta Touts Burndown Herbicide For Brome Management In Wheat
June 4, 2014
Arysta LifeScience North America recommends PRE-PARE Burndown Herbicide for effective brome management in winter wheat. Read More
HerbicidesFall Herbicide Applications More Effectively Manage Resistant Italian Ryegrass
May 14, 2014
Field studies show that a fall application of certain herbicides before weed emergence, leads to more successful crop planting and weed control in spring. Read More
Waterhemp in soybean stubble
HerbicidesThe Weed Resistance Problem: A Matter Of Billions
April 1, 2014
Not only is the amount of money being spent to control these yield robbers high, but the toll it has taken on the human population is growing lager by the day. Read More

Trending Articles

EquipmentAdvance Your Technology IQ At MAGIE
August 13, 2014
The Midwest AG Industries Exposition (August 20-21) is the place you need to be to see, study and evaluate how new advances in the equipment, operations, crop protection and fertility sectors can help your business prosper. Read More
HerbicidesScouting Key To Next Season’s Soybean Herbicide Program
August 12, 2014
When growing soybeans, growers need to think ahead to stay one step ahead of weeds. That means examining weed threats and evaluating which herbicides work best. Read More
StewardshipMichigan Agriculture Leaders On Toledo Water Ban: We Want To Be Part Of The Conversation
August 8, 2014
Leaders of Michigan agricultural organizations said Thursday that the government should not have a “knee-jerk reaction” based on last weekend’s water ban in Toledo due to fertilizer run-off in Lake Erie. Read More
CropLife 100BRANDT Acquires Lemon Ag Services
August 4, 2014
The acquisition of Lemon Ag fits BRANDT’s aggressive corporate strategy of providing superior agronomic advice and services for customers in central Illinois. Read More
Eric SfiligojThe Resurgence Of Crop Protection
August 4, 2014
Plenty of new offerings over the next few years should see a rebirth for the crop protection products category in terms of market share. Read More
LegislationUSDA Implements Key Farm Bill Crop Insurance Provision
July 30, 2014
The new Supplemental Coverage Option, available through the federal crop insurance program and set to begin with the 2015 crop year, is designed to help protect producers from yield and market volatility. Read More

Latest News

ManagementNCGA DuPont New Leaders Program Enters Sophmore Season
August 20, 2014
The National Corn Growers Association and DuPont are pleased to announce the second year of the NCGA DuPont New Leaders Program. Read More
FungicidesVerdesian Links Up With Mitsui, Hokusan
August 20, 2014
Mitsui Chemicals Agro, Inc., and Hokusan Co., announced the signing of an exclusive licensing agreement allowing Verdesian Life Sciences global access to its patented technology for suppressing mycotoxin contamination in wheat and barley. Read More
SprayersUniversity Of Illinois Introduces New Spray App
August 18, 2014
University of Illinois Extension has released a new smartphone app for making sprayer-related calculations. Pesticide Spray Calculator, or Spray Calc, Read More
Crop InputsSyngenta Names New Manager Of Federal Government Relati…
August 18, 2014
Laura Wood Peterson has joined Syngenta as manager of federal government relations, based in Washington, DC. Read More
ManagementExpert To Discuss Farmland Value, Rent At Farm Science …
August 18, 2014
While cropland values in Ohio increased in the past two years, they have remained flat in 2014, declining in some cases, according to an Ohio State University agricultural economist. Read More
EquipmentDeere Announces Factory Layoffs
August 18, 2014
Deere & Co. has announced it will reduce the size of its manufacturing workforce at some agricultural equipment factories in response to current market demand for its products. Read More
HerbicidesNew DuPont Afforia Herbicide Gives Crops A Clean Start
August 18, 2014
DuPont Afforia is a preplant herbicide for soybeans and other field crops that provides excellent burndown and residual control of many challenging weeds, such as marestail and waterhemp. Read More
Equipment21 Products Showcased At MAGIE 2014
August 18, 2014
The annual Midwest AG Industries Exposition is upon us. Here is CropLife IRON's look at some of the products visitors can expect to see at this week's event. Read More
EquipmentAGCO Seeks Nominations For 2014 Operator Of The Year
August 15, 2014
Ag retailers throughout the U.S. and Canada are encouraged to nominate their best applicators. Read More
EquipmentAdvance Your Technology IQ At MAGIE
August 13, 2014
The Midwest AG Industries Exposition (August 20-21) is the place you need to be to see, study and evaluate how new advances in the equipment, operations, crop protection and fertility sectors can help your business prosper. Read More
ManagementCropLife’s Buyers’ Guide Issue Now Availabl…
August 13, 2014
One of our most read issues of the year — the August Buyers' Guide — is ready to download on the iPad. This popular issue features equipment for "In The Field," "At The Plant" and "In The Office." Read More
WebinarsWebinars On Demand
August 13, 2014
Register for one of our upcoming Webinars or access our archive of past Webinars to view recordings of presentations that may be of interest to you. Read More
HerbicidesBASF: Fall Burndown Benefits Go Beyond Weed Control
August 12, 2014
While unpredictable weather may delay application timing of spring herbicides, more growers are adding a burndown application in the fall Read More
HerbicidesScouting Key To Next Season’s Soybean Herbicide P…
August 12, 2014
When growing soybeans, growers need to think ahead to stay one step ahead of weeds. That means examining weed threats and evaluating which herbicides work best. Read More
StewardshipNitrogen Efficiency Supports Environmental Stewardship
August 12, 2014
As growers prepare for another harvest, it’s important to consider how nitrogen stabilization not only supports healthy plant growth but also fosters environmental stewardship. Read More
Seed/BiotechMycogen Seeds Introduces 19 New Corn Hybrids For 2015
August 12, 2014
Many of the new hybrids feature Mycogen's SmartStax Refuge Advanced technology for maximum protection of the genetic potential and planting convenience. Read More
HerbicidesDow AgroSciences Introduces Enlist Ahead App For Enlist…
August 12, 2014
Designed for use with the Enlist Weed Control System, the app is a precision agriculture tool for maximizing weed control performance, managing weed resistance and making responsible applications of Enlist Duo herbicide with Colex-D Technology. Read More
CropLife 100CHS Announces Senior Leadership Team Changes
August 12, 2014
Current CHS strategic leadership team member Shirley Cunningham will assume a new role as executive vice president and chief operating officer, Ag Business and Enterprise Strategy. Read More