Paraquat fights glyphosate resistant weeds

Glyphosate resistant weeds ... paraquat can helpParaquat has an important role in fighting the increasing problem of glyphosate resistant weeds. These now threaten not only cost-effective weed control in many crops, but also the future of sustainable farming


Management and conservation of the natural resource base and the use of technological and organizational change in a manner that ensures continued agricultural production from the land for present and future generations. Such practices conserve land, water, and plant and animal genetic resources. They are environmentally non-degrading, technically appropriate, economically viable, and socially acceptable. Sustainability rests on the principle that we must meet the needs of the present without compromising the ability of future generations to meet their own needs. Therefore, stewardship of both natural and human resources is of prime importance.

Authoritative On-line References and Resources Information from the USDA's Alternative Agricultural Systems Information Center.
An in-depth article on the topic of glyphosate resistant weeds has been added to the Paraquat Information Center’s Knowledge Bank. You can read this article here.

Why glyphosate is important

Glyphosate is by far the world’s most widely used crop protection chemical and has been called a ‘once-in-a-century’ herbicide because of its unique combination of high efficacy and low environmental impact1. Like paraquat, glyphosate controls a very broad spectrum of weeds and is deactivated in soil. Glyphosate is especially important because it controls perennial weeds


Weeds that return year after year. Some die back in the winter but their roots remain alive and shoots reappear in spring; some don't die back and grow in size and stature the next season.

Authoritative On-line References and Resources

The International Weed Science Society represents individual associations around the world.
. These properties mean that glyphosate has been instrumental in the increasing adoption of no-till


Also known as conservation tillage or zero tillage is a way of growing crops from year to year without disturbing the soil through tillage ie cultivating the soil usually with tractor-drawn implements.

Authoritative On-line References and Resources  A portal for on-line information about no-till farming.
and other conservation tillage


Any tillage and planting system that covers 30 percent or more of the soil surface with crop residue after planting to reduce soil erosion by water.

Authoritative On-line References and Resources

Purdue University-based Conservation Technology Information Centre.
systems. Chemical weed control means that fields do not need to be plowed. This has many benefits, including reducing soil erosion


Displacement of solids (soil, mud, rock and other particles) usually by the agents of currents such as, wind, water, or ice by downward or down-slope movement.

Authoritative On-line References and Resources This site brings together reliable information on soil erosion from a wide range of disciplines and sources. It aims to be the definitive internet source for those wishing to find out more about soil loss and soil conservation.
, improving soil health and fertility, and reducing greenhouse gas emissions. 

Glyphosate resistance issues

The International Survey of Herbicide Resistant Weeds2 recognised 24 different species with glyphosate resistant biotypes in late 2012. Fields infested with these weeds have become common in certain parts of the world where glyphosate has been intensively used. Since the introduction of glyphosate tolerant GM crops many farmers have simplified their weed control operations, but have relied on spraying only glyphosate far too much. The new Paraquat Information Center Knowledge Bank article explains in detail how weeds have become resistant to glyphosate and the state of the problem throughout the world.

How Paraquat helps

A diverse set of weed control methods, including crop rotation and using herbicides with different modes of action is key to avoiding and addressing weed resistance. Paraquat, with its distinctive mode of action, is an ideal complement to glyphosate in many situations. One example is the popular ‘Double Knock’ of glyphosate followed by paraquat widely used in Australia. Similar approaches are used in Brazil. Information on these and many other ways in which paraquat is being used to fight glyphosate resistant weeds and ensure the continued availability of this herbicide vital to global food security can be found here.


  1. Duke, S O and Powles, S B (2008). Glyphosate: a once-in-a-century herbicide. Pest Management Science, 64, (4), 319-325
  2. International Survey of Herbicide Resistant Weeds


The brand name of the leading paraquat product is Gramoxone.