Sounding the Alarm

Since its discovery in 2004, glyphosate resistant Palmer amaranth has kept extension specialists and weed scientists with their hands full. When the resistant strain began popping up elsewhere – first in other counties, then other states, and finally in other regions of the Cotton Belt – those same industry experts were the first to sound the alarms. Four years later, they’ve got a better grasp on managing the problem.

But sounding the alarm is an every day challenge. That’s why Cotton Incorporated dedicated an entire session to the growing problem at their Cotton Management Seminar held in Tunica, MS, in November. The location of the seminar wasn’t just happenstance. Resistant pigweed is beginning to show up in alarming numbers in the Mid-South.

“We see glyphosate resistance as a national issue,” said Dr. Robert Nichols of Cotton Incorporated, while citing the problem’s westward movement from Georgia since 2004. “I would call it an emerging weed in the Mid-South, except our friends in Arkansas might disagree, seeing as how they already have this problem.” He went on to say that all Mississippi counties north of Highway 82 will be increasingly vulnerable to the problem in the near future.

Dr. Alan York of North Carolina State University further illustrated the movement of the weed epidemic. “2004 was the first sighting. We call that the epicenter, in Macon County, Georgia.”

To an expert like York, the weed’s success in such a wide variety of places is academic.

Designer Weed

“If you were going to design a weed, you’d use the blueprint for this one,” York says.

“(It has a) very efficient carbon fixation. It is water use efficient, and has very high temperature tolerance – optimum for photosynthesis at 180 degrees. So when it’s hot and dry, and the crop is struggling to hang on, this thing is happy. It grows very fast – an inch or two a day – and gets very big. Obviously it’s very competitive with the crops.”

In short, the resistant pigweed travels fast, appears quickly, and perhaps most problematically, grows to an unmanageable size almost overnight. At 2 inches tall, the weed can be easily managed. The problem of course, is that it cannot be easily spotted at 2 inches, and often by the time you see it, it has grown too large to kill with conventional chemistry.

“The difference between where it’s manageable and the size where it’s too big to control in a good growing environment might be 72 hours,” says Dr. Larry Steckel with the University of Tennessee. “We’re talking hours to be able to get out there. And as big as a lot of our growers have gotten, that’s going to be a challenge to get across that many acres, over the top, in that time period.”

A Greater Challenge

The general consensus among weed experts is that while Roundup Ready technology made life easier for growers, it also lulled them into a false sense of security. Because of the proliferation of the resistant gene, they say, cotton producers must unlearn some of the habits that came about with Roundup Ready practices.

“We all know that Roundup Ready technology was a good thing. It was idiot proof. But what it did was make our growers into weed sprayers. This resistance is going to make us go back and be weed managers,” says York.

Because of the plant’s ability to get out of hand so quickly, Steckel and other leading weed scientists are advising growers from the Southeast to the Mid-South to take pre-emptive steps against resistant pigweed.

“Even without the glyphosate resistance, we’re making a recommendation for something residual either pre-emergence, or maybe its Valor pre-plant and in that case we’d probably still want to follow it with something pre. We are trying to limit our PPO inhibitors to one application per year. And we are trying to not depend on ALS materials any more than we have to,” says Steckel.

Leave a Reply

Weed Control Stories
Weed Control

Post-Direct and Hooded Options for Pigweed Control

July 7, 2016

Considering how Palmer amaranth – or pigweed – seems to just keep coming this year, directed layby applications are critical for maintaining consistent pigweed control.

Weed Control

Preserving Weed Management Tools through Good Stewardship

May 9, 2016

Cotton growers looking for ways to cut trips across their fields to save money and time could be doing more harm than good – especially when it comes to weed management.

Weed Control

Participation Urged for Texas Palmer Amaranth Study

May 3, 2016

Texas A&M AgriLife Extension is conducting an online survey to determine weed management systems commonly used by cotton growers, as well as the current extent of glyphosate-resistant Palmer amaranth in West Texas.

Weed Control

How to Manage PPO Resistant Pigweed in Cotton

February 4, 2016

Mississippi State Extension specialists say managing Palmer amaranth with multiple resistance to glyphosate, ALS and PPO herbicides will be complicated, but not impossible.

Weed Control

Producers Embrace Diverse Herbicide Programs

December 8, 2015

While growers wait on regulatory approval of new options, residual herbicides become increasingly important.

Weed Control

EPA Reconsidering Enlist Duo Registration; Dow Responds

November 27, 2015

Citing “new information regarding potential synergistic effects between the two ingredients on non-target plants,” EPA is reconsidering the registration of Dow AgroSciences’ Enlist Duo herbicide for corn, soybeans and cotton.

Weed Control

Post-Harvest Field Prep Can Reduce Weed Problems at Planting

October 27, 2015

As growers look across their harvested fields, they should be thinking about what’s needed to get ready for 2016 plantings.

Around The Gin
Product News

It’s a Deal: Bayer to Acquire Monsanto

September 14, 2016

Bayer and Monsanto have announced an agreement under which Bayer will acquire Monsanto for approximately $66 billion in an all-cash transaction.

Product News

How Fiber Quality Became So Valuable

September 14, 2016

Textile expert Dean Etheridge explains the meteoric rise of fiber quality on the global market.

Product News

Cotton Cultivated Website Adds Custom Weather Feature

September 1, 2016

Cotton Cultivated – Cotton Incorporated's producer information website – now features a new weather tool tailored for cotton growers.

Product News

ChemChina/Syngenta Deal Gets U.S. Foreign Investment Approval

August 22, 2016

ChemChina and Syngenta have received a key clearance for the proposed consolidation of the companies.

Product News

Enlist Cotton Trait Earns Full Export Approval

August 10, 2016

Cotton varieties containing Dow AgroSciences’ Enlist trait now have full export approval in key countries.

Product News

Spray Equipment Offer Helps Maximize On-Target Applications

August 3, 2016

A new spray technology equipment offer can help growers participating in Roundup Ready PLUS Crop Management Solutions upgrade their sprayers to maximize on-target applications.

Product News

EPA Allows Sale and Use of Existing Belt Inventory

August 2, 2016

The U.S. EPA’s Environmental Appeals Board has upheld an earlier decision to cancel registration for Bayer's insecticide Belt, but is allowing sales of existing stocks to growers for use.

Product News

Indigo Launches Water Efficiency Product for Cotton

July 26, 2016

Boston-based research firm Indigo has launched its first commercial product – Indigo Cotton – which helps improve the cotton plant’s water use efficiency.

Latest News
Weed Control

Post-Direct and Hooded Options for Pigweed Control

July 7, 2016

Considering how Palmer amaranth – or pigweed – seems to just keep coming this year, directed layby applications are critical for maintaining consistent pigweed control.

Weed Control

Cut Down on Weed Escapes

June 28, 2016

As new types of resistance appear, 2016 could become a banner year for pigweed escapes.

Weed Control

New Webcast Outlines Flag the Technology Program

June 22, 2016

A new webcast explaining the use and value of the University of Arkansas’ Flag the Technology program has been added to the Focus on Cotton online series from the Plant Management Network and Cotton Incorporated.

Weed Control

Preserving Weed Management Tools through Good Stewardship

May 9, 2016

Cotton growers looking for ways to cut trips across their fields to save money and time could be doing more harm than good – especially when it comes to weed management.

Weed Control

Participation Urged for Texas Palmer Amaranth Study

May 3, 2016

Texas A&M AgriLife Extension is conducting an online survey to determine weed management systems commonly used by cotton growers, as well as the current extent of glyphosate-resistant Palmer amaranth in West Texas.

Weed Control

How to Manage PPO Resistant Pigweed in Cotton

February 4, 2016

Mississippi State Extension specialists say managing Palmer amaranth with multiple resistance to glyphosate, ALS and PPO herbicides will be complicated, but not impossible.

Weed Control

Producers Embrace Diverse Herbicide Programs

December 8, 2015

While growers wait on regulatory approval of new options, residual herbicides become increasingly important.

Weed Control

EPA Reconsidering Enlist Duo Registration; Dow Responds

November 27, 2015

Citing “new information regarding potential synergistic effects between the two ingredients on non-target plants,” EPA is reconsidering the registration of Dow AgroSciences’ Enlist Duo herbicide for corn, soybeans and cotton.

Weed Control

Post-Harvest Field Prep Can Reduce Weed Problems at Planting

October 27, 2015

As growers look across their harvested fields, they should be thinking about what’s needed to get ready for 2016 plantings.

Weed Control

Enlist Cotton Gets the Greenlight

September 7, 2015

When USDA deregulated Dow AgroSciences’ Enlist cotton trait system in late July, company representatives breathed a sigh of relief…and started gearing up for the “fun part.”

Weed Control

Cover Crop Considerations for This Fall

August 26, 2015

Growers should plan now for fall cover crops to help improve control of herbicide-resistant Palmer amaranth in next year's row crops.

Weed Control

Rain-Fed Weeds in Cotton Need Mid-Season Control

August 7, 2015

The early season rainfall in Texas has caused high weed pressure in cotton throughout the state, especially in the Rolling Plains.

Weed Control

Time to Clear Pigweeds from the Field

July 14, 2015

Now that most weed control treatments are ending, it’s time to look for ways to effectively hand weed and remove surviving pigweed plants from the field.

Weed Control

Rains Create Texas-Sized Weed Challenges

June 30, 2015

Drought-busting rains in May have created a mixed bag for cotton – and weed control – across Texas.

Weed Control

Mixing Up the Right Solution for Weeds

June 2, 2015

Proper use of tankmixes – and maybe a sharp hoe – are musts for summer weed control.