The Resistant Weeds Epidemic

As resistant weeds become more common in crop fields across the country, the entire agricultural community is scrambling to keep pace.

As a long-time independent ag retailer in St. Marys, KS, Doyle Pearl of J.B. Pearl Sales & Service Inc. has grown used to some interesting sights in his grower-customer fields. However, on a recent visit to one customer’s farm, Pearl at first thought he had somehow ended up on a holiday-oriented operation instead of one devoted crops.

“When I looked into the field, I at first thought this grower was harvesting Christmas trees,” says Pearl. “But when I looked closer, I saw these large, bushy plants weren’t pine trees, but weeds. It was then I realized that herbicide-resistant Palmer amaranth had arrived in our area.”

Unfortunately, Pearl is not alone in witnessing this kind of sight. Since the first herbicide-resistant marestail was discovered in Delaware in 2000, the number of similar hard-to-control weeds has rapidly spread across the U.S. At last count, say experts, there were some 14 species of weeds showing single or multiple forms of herbicide resistance in more than 30 states affecting thousands of acres of cropland.

“Palmer amaranth is a huge problem for growers because we’ve seen some plants that have had three applications of Roundup Ready WeatherMax and survived,” says Dwight Lingenfelter, a weed scientist in the department of plant science at Penn State University.

“Waterhemp is another weed that has shown resistance to multiple forms of herbicides and modes of action. There’s even one population of waterhemp that was recently discovered in Iowa that is showing some resistance to 2,4-D.”

Even worse, say industry observers, the cost of dealing with these herbicide-resistant weeds is quickly becoming an issue. For example, according to Dr. Larry Steckel, a weed scientist with the University of Tennessee, resistant Palmer amaranth cost Tennessee soybean growers more than $200 million in the past two years in increased herbicide costs, application ex­penses and yield loss.

Seeds Of Discontent

And if the plants themselves aren’t bad enough, ag retailers and their grower-customers need to be equally concerned with the seeds these herbicide-resistant weeds produce. According to Willowood USA’s Dr. Jeff Stachler, one waterhemp plant discovered in Moorhead, MN, produced 644,000 seeds. In another example, running water following a rain event in a field with Palmer amaranth present was found to contain 1 million seeds only 20 minutes after the storm.

Weed Resistance Issues Chart Weed Resistance Issues Chart

“If one plant produces 100,000 seeds with only 25% emergence and 10% of those plants survive, these resistant plants can produce up to 6.25 million plants two years later,” says Stachler.

For the most part, ag retailers understand that herbicide-resistant weeds are a major problem for their grower-customers. According to a survey recently conducted by CropLife® magazine, 79% of dealerships and cooperatives say weed resistance is a serious or very serious problem in their areas. Similarly, 51% of the grower-customers themselves view resistant weeds as a serious to very serious problem (see graphs).

The Quest For Control

When it comes to figuring out how to combat these resistant weeds, opinions from experts are varied. Some have advocated hand weeding mixed with alternatives to traditional herbicide programs as an option. “In 2010, it took 110 hours to completely hand-weed a 50-acre field, costing $33 per acre charge based upon a $15 per acre rate,” says Stachler. “In 2011, with the same herbicide program, it took only five hours to completely hand-weed this field — a cost of only $1.50 per acre.”

In other countries such as Australia, growers combating herbicide-resistant weeds have adopted an all-out war on the seeds. To achieve control here, growers have taken to baling their field trash into bundles used for livestock feed or burning this residual with flame-producing equipment that is pulled along behind the harvester.

Thankfully, here in the U.S., the situation isn’t quite as extreme just yet and 81% of ag retailers polled by CropLife® say they presently have the tools and knowledge needed to help growers manage their resistance issues.

However, as Penn State’s Lingenfelter says, ag retailers shouldn’t count on a completely new herbicide to come along and solve the problem of resistant weeds. “There have been plenty of new products introduced into the market to combat resistant weeds over the past few years,” he says. “But none of these offer a new mode of action option. The fact of the matter is there has been no new mode of action introduced into the herbicide market for the past 20 years. And even if a new molecule was discovered tomorrow that might offer a new mode of action for weed control, it wouldn’t be available for use on the market for another 10 years or better.”

Instead, says Willowood’s Stachler, retailers and growers should get used to viewing weeds in the field in a whole new light. “It is best to assume that any plant of single species present in a field is resistant at some level,” he says.

Topics:

Leave a Reply

Weed Resistance Stories

Weed ResistanceWeeds: The Fearsome Five
October 1, 2013
Although there are currently dozens of weeds that show some kind of resistance to herbicides, these five are the most troublesome. Read More
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

Trending Articles

FertilizerFall Fertility 2014: Forecasting Fertilizer Use
September 7, 2014
Great crops this year have tapped the soil, and fall work is definitely called for, but how challenging will that get? Read More
CropLife 100CHS To Build $3 Billion Fertilizer Plant In North Dakota
September 5, 2014
The fertilizer plant in Spiritwood will be the single largest investment in CHS history, as well as the single largest private investment project ever undertaken in North Dakota. Read More
EquipmentNew Holland Acquires Miller-St. Nazianz
September 3, 2014
The assets of Miller acquired as part of the transaction will become part of New Holland Agriculture, a CNH Industrial brand, building on a successful four-year partnership between the two companies. Read More
CropLife 100Pinnacle Acquires East Kansas Chemical
September 2, 2014
Ranked 82nd on the CropLife 100, East Kansas Chemical will operate as part of Pinnacle's Performance Agriculture brand. Read More
MAGIE 2014 ShowStopper
EquipmentJohn Deere Again Wins MAGIE ShowStopper Award
August 25, 2014
For the second consecutive year, John Deere was honored at the Midwest AG Industries Exposition (MAGIE) for its new R4045 sprayer. Read More
ManagementExpert To Discuss Farmland Value, Rent At Farm Science Review
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

Latest News

Equipment2014 Product Of The Year Voting
September 19, 2014
Many new products were introduced to the ag retail marketplace this year. From this group, CropLife IRON and its consulting partners have selected five finalists for the Product of the Year award. Please cast your vote today to help us determine the winner. Read More
Equipment2014 Farm Science Review Crowd Tops 2013 Show
September 19, 2014
The 52nd annual Ohio State University Farm Science Review welcomed more than 130,000 farmers, industry professionals, FFA students and agricultural enthusiasts during the three-day event. Read More
Seed/BiotechUSDA Approves Enlist Following Rigorous Review
September 18, 2014
Dow AgroSciences now awaits EPA registration of Enlist Duo herbicide, the companion herbicide to the Enlist traits, which is expected in the near future. Read More
BlendersYargus Appoints New Plant Manager
September 18, 2014
Steve Shaffer will direct and coordinate daily operations at the company’s Marshall, IL, manufacturing plant, where the Layco line of material handling equipment is produced. Read More
CropLife 100Pinnacle Acquires Kansas-Based Cedar Ridge Supply
September 16, 2014
Cedar Ridge Supply will operate as part of Pinnacle's Performance Agriculture brand. Read More
StewardshipSecretary Vilsack Highlights Innovative Conservation Ef…
September 15, 2014
Nearly $16 million in Conservation Innovation Grants (CIGs) will be awarded to 47 organizations to help develop cutting-edge ideas to accelerate innovation in private lands conservation. Read More
Seed/BiotechSyngenta Responds To Cargill Lawsuit
September 15, 2014
Syngenta believes that the lawsuit is without merit and strongly upholds the right of growers to have access to approved new technologies. Read More
Equipment2014 Farm Science Review Launches Mobile App
September 15, 2014
Smartphone and tablet users planning on attending the 2014 Farm Science Review can now download this year’s customized mobile application. Read More
CropLife 100Southern States Coop Grower Sets Georgia Soybean Yield …
September 15, 2014
Georgia farmer Randy Dowdy's soybeans yielded an astonishing 110.66 bushels per acre, crushing the previous record of 82 bushels-per-acre. Read More
NIMITZ Treated vs Untreated pepper plant
InsecticidesNIMITZ Nematicide Approved By EPA
September 12, 2014
NIMITZ is a novel, non-fumigant nematicide with simplified application features, user safety and an active ingredient with a unique mode of action. Read More
InsecticidesMarrone Bio Innovations Receives Patent For Chromobacte…
September 11, 2014
The patent is the first step for MBI in developing a commercially viable product to inhibit infestations of corn rootworm larvae across America and other regions. Read More
HerbicidesDow AgroSciences: Keeping The Pipeline Stocked
September 11, 2014
Dow AgroSciences is embracing product diversity to drive the company’s future. Read More
CropLife 100CHS Is Official Partner Of New St. Paul Ballpark
September 10, 2014
The new ballpark in St. Paul, MN, officially became CHS Field with Twin Cities-based CHS Inc. revealed as the naming rights partner. Read More
EquipmentHagie Honors Farming Stewardship Leaders
September 10, 2014
The Iowa Farm Environmental Leader award recognizes Iowa farmers as environmental leaders that are committed to healthy soils and improved water quality. Read More
Precision AgPlantBeat: Your Plants’ Pulse In The Palm Of Your Han…
September 10, 2014
A new agronomic monitoring and recommendation service from Phytech could rewrite the book on real-time plant health status monitoring. Read More
StewardshipCCAs Making Headway With 4R Program In Lake Erie Wester…
September 9, 2014
Certified Crop Advisers are implementing the 4R Nutrient Stewardship Certification program in Lake Erie's Western Basin to improve water quality. Read More
MicronutrientsMicronutrients Going Macro
September 9, 2014
Between 2014’s fantastic growing conditions and a heightened awareness on plant nutrition, the major players in micronutrients are gearing up for another big year. Read More
Crop InputsFMC Announces Cheminova Takeover
September 8, 2014
FMC Corporation today announced that it has signed a definitive agreement to acquire Cheminova, a wholly owned subsidiary of Auriga Industries. Read More