Nine Weeds Resistant To Glyphosate

In a recent presentation to EPA, officials from the Weed Science Society of America (WSSA) reported that nine weed species in the U.S. now have confirmed resistance to glyphosate. Among these weeds are strains of common ragweed (Ambrosia artemisiifolia), common waterhemp (Amaranthus rudis), giant ragweed (Ambrosia trifida), hairy fleabane (Conyza bonariensis), horseweed (Conyza canadensis), Italian ryegrass (Lolium multiflorum), johnsongrass (Sorghum halepense), Palmer amaranth (Amaranthus palmeri) and rigid ryegrass (Lolium rigidum).

“Unfortunately it is too late to prevent glyphosate resistance from developing,” says David Shaw, WSSA president. “It’s a problem that is already with us. The challenge now is to adopt effective management techniques that can keep resistance from spreading.”

The consequences of resistance are particularly troublesome for farmers who grow soybean, corn, cotton and sugar beet crops genetically engineered to tolerate glyphosate. Many of these farmers rely almost exclusively on glyphosate for weed control throughout the growing season. Using a single herbicide, though, increases the odds that the weed population will shift to resistant plants that are able to escape treatment and compete with crops for moisture and nutrients.

University scientists recommend a number of techniques for preventing or managing resistance. One of the most common recommendations is to rotate the types of herbicides used for weed control – making it tougher for weeds to adapt. Shaw says that initially many farmers were slow to recognize the seriousness of glyphosate resistance and to adopt this best management practice. However, educational programs in the last few years have greatly increased grower awareness and management efforts.

“One issue may have been the mistaken perception that adopting resistance management practices will cost more, since glyphosate tends to be very affordable,” Shaw says. “But studies show just the opposite is true.”

In a four-year research project now underway in six key agricultural states (Illinois, Indiana, Iowa, Mississippi, Nebraska and North Carolina), researchers are comparing the economics of university-recommended, herbicide resistance management programs with the use of glyphosate as an exclusive treatment for weed control. As of the end of the third year of the study, researchers say the net returns on fields managed according to recommended best practices are equal to or greater than the returns on those where glyphosate is used alone. Increased yields appear to offset any increase in herbicide costs.

“When glyphosate was first introduced for weed control, its unique way of inhibiting protein synthesis and growth in plants led many to believe that resistance would not be an issue,” Shaw says. “Obviously that prediction was wrong. However, best management practices can slow the development of resistant weeds, and one effective approach is to rotate glyphosate with herbicides that work very differently.”

Source: press release Weed Science Society of America

Leave a Reply

2 comments on “Nine Weeds Resistant To Glyphosate

  1. Sure, just spray your roundup ready corn/soy/cotton/sugarbeets with 2,4D. Maybe farmers should have listened to the ecologists who have been predicting this all along.

  2. Sure, just spray your roundup ready corn/soy/cotton/sugarbeets with 2,4D. Maybe farmers should have listened to the ecologists who have been predicting this all along.

Featured Stories
upclose of Israeli apple harvester
Fruits
May 28, 2016
Orchard Automation Is On The Horizon
Industry experts say the advent of fully automated orchard tasks are on the cusp of happening — with a few companies leading the automotive harvest charge. Read More
IFTA Washington Day3 6
Apples & Pears
May 27, 2016
Washington Apple Commission Elects New Leaders
The commission board also approved the export budget of $7.7 million for the upcoming 2016-17 crop, based on a crop of 135 million cartons. Read More
As this view of the San Luis Reservoir shows, California's drought is far from over. (Photo credit: David Eddy)
Fruits
May 27, 2016
California Drought Far From Over For
To preserve orchards and vineyards, growers are expected to fallow up to 350,000 acres of corn, wheat, cotton and alfalfa. Read More
These workers use a platform from Automated Ag for hand thinning. (Photo credit: Christina Herrick)
Apples & Pears
May 27, 2016
How Best To Integrate Man And Machine
If you want to implement labor-saving mechanization, you should start the conversation with the end user – your employees. Read More
Crowd protesting GMOs stock image FEATURE
Farm Marketing
May 27, 2016
Consumers Don’t Really Know What GMO Means, New Study Finds
A study from the University of Florida confirms what many farm marketers suspected: consumers don't understand genetically modified food and organisms as well as they think they do. In fact, 80% of consumers think food containing DNA should be labeled (almost as many who think GMO food should be labeled). Read More
Asian citrus psyllid closeup
Insect & Disease Update
May 27, 2016
Alabama Agriculture Department To Conduct Citrus Psyllid Survey
Currently, Alabama is the only citrus-growing state that has not yet detected citrus greening. Read More
Ready To Spring
Insect Control
May 26, 2016
Temperature, Location Key To Predicting Leaffooted Bug Pressure
This year, leaffooted bugs are expected to be a significant problem in almonds and pistachios, but watching temperature and the Read More
First-year impact of Prunus replant disease at the Firebaugh replant trial; stunted trees in the foreground row were planted in plot of non-fumigated replant soil. (Photo credit: University of California Agriculture)
Fruits
May 26, 2016
Consider Fumigating For Nematodes Before Replanting Almonds, Stone Fruit
Stone fruit and almond growers looking to replant orchards might want to invest in soil samples to assess nematode populations Read More
An open air farm dinner at Tangletown's farm FEATURE
Farm Marketing
May 26, 2016
Farm Dinners: Your Most Powerful Marketing Tool?
Farm dinners are a hassle. They’re expensive. And ridiculously effective. Read More
The Latest
Fruits
May 28, 2016
Orchard Automation Is On The Horizon
Industry experts say the advent of fully automated orchard tasks are on the cusp of happening — with a few companies leading the automotive harvest charge. Read More
Apples & Pears
May 27, 2016
Washington Apple Commission Elects New L…
The commission board also approved the export budget of $7.7 million for the upcoming 2016-17 crop, based on a crop of 135 million cartons. Read More
Fruits
May 27, 2016
California Drought Far From Over For
To preserve orchards and vineyards, growers are expected to fallow up to 350,000 acres of corn, wheat, cotton and alfalfa. Read More
Apples & Pears
May 27, 2016
How Best To Integrate Man And Machine
If you want to implement labor-saving mechanization, you should start the conversation with the end user – your employees. Read More
Farm Marketing
May 27, 2016
Consumers Don’t Really Know What G…
A study from the University of Florida confirms what many farm marketers suspected: consumers don't understand genetically modified food and organisms as well as they think they do. In fact, 80% of consumers think food containing DNA should be labeled (almost as many who think GMO food should be labeled). Read More
Insect & Disease Update
May 27, 2016
Alabama Agriculture Department To Conduc…
Currently, Alabama is the only citrus-growing state that has not yet detected citrus greening. Read More
Insect Control
May 26, 2016
Temperature, Location Key To Predicting …
This year, leaffooted bugs are expected to be a significant problem in almonds and pistachios, but watching temperature and the Read More
Fruits
May 26, 2016
Consider Fumigating For Nematodes Before…
Stone fruit and almond growers looking to replant orchards might want to invest in soil samples to assess nematode populations Read More
Farm Marketing
May 26, 2016
Who Grows Organically — And Who Doesn…
We surveyed 816 fruit and vegetable growers and found that farm marketers and vegetable growers are much more likely than their peers to embrace the practice. Read More
Farm Marketing
May 26, 2016
Farm Dinners: Your Most Powerful Marketi…
Farm dinners are a hassle. They’re expensive. And ridiculously effective. Read More
Cucurbits
May 25, 2016
Whitefly Threat Has Florida Growers On H…
Researchers, state agencies working together to prevent a potential outbreak. Read More
Crop Protection
May 25, 2016
More Apps Help Growers Identify Insects …
Berries, apples, pears, and cherries now rolled into new app series from Clemson University. Read More
Citrus
May 25, 2016
Monsanto Says Bayer Bid ‘Financially Ina…
Proposal cited as undervalued, not able to address financial, regulatory risks. Read More
Stone Fruit
May 25, 2016
Researchers Study Why Cherry Cracking Af…
German researchers studied how water uptake and fruit skin determined a cultivar’s susceptibility to cherry cracking. Read More
Farm Management
May 25, 2016
Report Highlights Benefits Of Trans-Paci…
National Potato Council says report from the International Trade Commission offers the benefits the free trade agreement would offer growers. Read More
Fruits
May 25, 2016
Farm Bureau Says EPA, Army Corps Of Engi…
AFBF told Congress that the Army Corps' novel interpretations of environmental law are threatening farmers in California and other areas of the country. Read More
Citrus
May 25, 2016
NRCS Invests $4.3 Million To Combat Clim…
The Natural Resources Conservation Service in California is committing funds to help farmers and ranchers mitigate the effects of climate change and help to reduce greenhouse gas emissions. Read More
Citrus
May 24, 2016
Panama Canal Expansion To Bring Trade Op…
Agriculture Commissioner Adam Putnam says a confluence of events is putting the state's producers in a good spot to open new markets. Read More
[gravityform id="62" title="false" description="false"]