Weeds: The Fearsome Five

Although there are currently dozens of weeds that show some kind of resistance to herbicides, these five are the most troublesome.

Palmer amaranthPALMER AMARANTH | Amaranthus palmeri
• One of 865 members of the pigweed family. Grows faster and is more competitive than any other of the pigweed family.
• Has male and female plants, allowing for greater genetic variability and adaptability.
• Each plant can produce up to 1 million seeds.

WaterhempCOMMON/TALL WATERHEMP | Common Waterhemp (Maranthus rudis); Tall Waterhemp (Amaranthus tuberculatus)
• Members of the pigweed family.
• Tall waterhemp has smooth, erect stem that can grow more than 8 feet tall. Male and female flowers found on separate plants.
• Germinates over relatively long time period and grows rapidly.
• Waxy, narrow leaves slows herbicide uptake.
• Prolific seed producer (more than 250,000 seeds per plant). Seed can be dispersed over long distances, also is readily transported when equipment is moved from field to field.

MarestailHORSEWEED/MARESTAIL | Conyza canadensis
• One of the most common weeds in eastern and central parts of U.S.
• Well-adapted to no till-crop production; can quickly spread to many habitats along field edges and roadsides.
• Produces up to 200,000 tiny seeds per plant that are wind-dispersed over great distances. Up to 80% of seeds can germinate immediately
after dispersal.

Giant RagweedGIANT RAGWEED | Ambrosia trifida
• One of largest annuals, averages 5 feet in height, but can grow as large as 10 feet.
• Can produce over 11,000 seeds per plant without competition.
• In Midwest, can reduce corn yield up to 37%, soybean yield up to 52%.

Common LambsquartersCOMMON LAMBSQUARTERS | Chenopodium album
• Grows to more than 5 feet tall.
• Can produce 150,000 seeds per plant. Seeds can germinate in soil for a number of seasons.
• Highly competitive to plants. Just over 75 lambsquarters per square yard can reduce soybean yield by 50%.
• Difficult to control with postemergence herbicides. Wax on leaf surface slows herbicide movement into leaf and can affect subsequent control.

Topics:

Leave a Reply

Weed Resistance Stories

Weed ResistanceWeed Management Program Profiles
October 1, 2013
Here’s quick look at weed control strategies and their cost. Read More
Weed ResistanceRecognizing Resistance
October 1, 2013
Recognizing the presence of herbicide-resistant weeds and formulating a total management plan is becoming more important than ever. Read More
Mature Waterhemp in Corn
Weed ResistanceWhen Weed Control Goes Wrong
October 1, 2013
Beyond the possibility of resistance developing, ineffective control exacts cost to growers in lost yield. Read More
Weed ResistanceOptimizing Applications
October 1, 2013
Sophisticated tank mixes, multiple adjuvants and surfactants — this is the future of herbicide application. Read More
Top 100 Articles
CropLife 100Southern States Coop Hosting Drone Flight This Friday
August 3, 2015
Southern States Cooperative — No. 9 on the CropLife 100 — is hosting an FAA-approved drone demonstration at Grandview Farms Read More
CropLife 100Allied Ag Distributors Adds Four New Owners
July 30, 2015
Aligned Ag Distributors LLC has announced the addition of four new customer/owners to Franklin Holding Co. LLC. They are: The Read More
CropLife 100Pinnacle Purchases California-Based Specialty Crops Retailer
July 20, 2015
Pinnacle Agriculture Holdings has successfully acquired California-based NH3 Service Co.  Operating as part of Pinnacle’s Performance Agriculture brand, the new locations Read More
Asmus Farm Supply liquid fertilizer facility features 20,000 square feet
CropLife 100Slideshow: Asmus Farm Supply Shows Off Its New Liquid Fertilizer Facility
July 15, 2015
Asmus Farm Supply, Rake, IA, recently added a new liquid fertilizer facility to its company operations. The new liquid fertilizer Read More
CropLife 100Wilbur-Ellis Feed Division Facilities Receive Safe Feed/Safe Food Certification
July 13, 2015
Wilbur-Ellis Co.’s Feed Division, a marketer and distributor of value-added feed ingredients for the aquaculture, livestock and pet food industries Read More
CropLife 100BRANDT Expands To Brazil With Acquisition
July 8, 2015
BRANDT has acquired a majority interest in Target Brasil Fertilizantes Ltda. through its Brazilian subsidiary. Target Brasil manufactures, distributes and Read More
Latest News
Young corn plants
Crop InputsNufarm Reorganizing Ag, Industrial Vegetation Managemen…
August 3, 2015
Today Nufarm announced a reorganization of its Agriculture and Industrial Vegetation Management sales and marketing organizations effective August 1, 2015. Read More
StewardshipExcellence Through Stewardship Reaches 30 Members
August 3, 2015
Excellence Through Stewardship, a non-profit that promotes the adoption of best practices and stewardship in agricultural technology, reached the milestone Read More
CropLife 100Southern States Coop Hosting Drone Flight This Friday
August 3, 2015
Southern States Cooperative — No. 9 on the CropLife 100 — is hosting an FAA-approved drone demonstration at Grandview Farms Read More
CropLife 100Allied Ag Distributors Adds Four New Owners
July 30, 2015
Aligned Ag Distributors LLC has announced the addition of four new customer/owners to Franklin Holding Co. LLC. They are: The Read More
FungicidesReport: Sudden Death Syndrome Symptoms Appearing In Soy…
July 30, 2015
Last week, symptoms of sudden death syndrome (SDS) began to appear in April 15-planted soybeans at the University of Illinois’s Read More
Seed/BiotechAdvanta Seeds Adds New Phoenix Corn Hybrids
July 30, 2015
Corn growers in the High Plains and Western states have new options available for the 2016 growing season from Advanta Read More
ManagementTechnology and agriculture: a Futurist’s Perspective
July 30, 2015
Futurist David Zach, speaking at this week’s InfoAg Conference in St. Louis, shared thoughts on the benefits and limitations of Read More
Biofuels Plant in Lousiana
Industry NewsIdle Biofuels Plant In Louisiana To Reopen As Ammonia F…
July 30, 2015
A Lithuania-based company plans to spend $265 million to reopen an idle biofuels refinery in Grant Parish as an ammonia Read More
FFA at Monsanto Booth at the 2015 National Farm Machinery Show
Industry NewsFive Students Receive The 2015 Monty’s Plant Food Compa…
July 29, 2015
This fall, five college-bound students will have financial support through the Monty’s Plant Food Company FFA Scholarship. All five scholarship Read More
GYPSOIL Blendable Pellets
Crop InputsBeneficial Reuse Management Launches Pelletized Gypsum …
July 29, 2015
Beneficial Reuse Management (BRM) announced this week at Ag Media Summit that its GYPSOIL Pelletized Products Division will open a Read More
StewardshipOhio Water Quality Project To Determine How Much Phosph…
July 27, 2015
Researchers with the College of Food, Agricultural, and Environmental Sciences at The Ohio State University are looking for farmers in Read More
FertilizerKoch Agronomic Services Launches N-TEGRATION Technology
July 27, 2015
Koch Agronomic Services, LLC (KAS) has launched  N-TEGRATION Technology, a process technology platform designed to enable production of enhanced efficiency fertilizers at Read More
HerbicidesExpert: IARC Herbicide Classifications Leading To Confu…
July 24, 2015
Few people in the crop protection industry had heard of the International Agency for Research on Cancer (IARC) before this Read More
ManagementFCI Trade Summit Update & Precision Tank Turns 50
July 23, 2015
Editors Dave Frabotta and Eric Sfiligoj discuss the upcoming FCI Trade Summit in Las Vegas, NV, and how Precision Tank Read More
Palmer pigweed seedhead in cotton
HerbicidesUSDA Deregulates Dow AgroSciences’ Enlist Cotton Trait
July 23, 2015
The USDA today issued its decision deregulating Dow AgroSciences’ Enlist cotton trait in the U.S. The USDA has now completed its Read More
Industry NewsVerdesian Life Sciences Showcases Versatile Product Por…
July 23, 2015
Technology has revolutionized agriculture by bringing farmers, retailers and distributors to the forefront of the digital age. To meet the Read More
FertilizerWSJ: Cf Industries Exploring Merger With Dutch Chemical…
July 23, 2015
U.S. fertilizer maker CF Industries is in advanced merger talks with Amsterdam-listed chemical company OCI NV, the Wall Street Journal Read More
HerbicidesNufarm Releases New Panther SC Herbicide
July 23, 2015
Nufarm has announced the availability of new Panther SC herbicide. Panther SC is the first liquid formulation of flumioxazin available Read More