Glyphosate is one of the most famous pesticides in the world. It is the most frequently used herbicide worldwide and in the EU.

In recent years, it has been under much scrutiny with some calling for it to be banned and major court cases taking place.

The product, once owned by Monsanto and famous for its use with GM Roundup Ready crops, is now owned by major chemical giant Bayer.

Its registration is constantly under threat.

It is currently approved for use in the EU until 15 December 2022.

Glyphosate in Irish farming

When glyphosate first came on to the market it tackled a major weed problem on Irish farms, scutch grass.

The competitive weed had the ability to take over fields and still does today, spreading via rhizomes.

Glyphosate is still one of the main pesticides used in grass weed control in cereal crops. As weeds like blackgrass and Italian ryegrass become more common, glyphosate can play an important role in their control. With no 100% control available for blackgrass, glyphosate plays a major role. Crops are desiccated in the UK each year to prevent its spread.

Glyphosate can still be used to control grass weeds in cereal crops pre-harvest, but this is not allowed where the crop is destined for the human food chain. Food-grade crops are tested for pesticide residues.

Its use is generally associated with tillage farming so it will surprise many readers that 50% of the glyphosate used in Irish farming is for grass reseeding. Old grass swards are burned off ahead of establishing a new one in min-till reseeding.

Carbon and cover crops

As we look at the sustainability of agriculture and hear more about carbon sequestration, reduced tillage has a role to play. Some grass weeds can be more prominent on land under min-till and glyphosate can help control.

Many tillage farmers who use a direct-drill establishment system plant into green cover. This green cover usually needs to be destructed to allow the cash crop to grow and this can be done with glyphosate before or after sowing.

The cover crops are good for soil structure while protecting the soil from erosion. They can also increase soil organic matter (carbon content) and soak up nutrients.

Farmers also try to use alternative methods to pesticides, such as rolling during frost.

Others will use tillage to control weeds. The chemical needs to be the last resort where good integrated pest management is being carried out, but glyphosate plays a key role in all tillage systems at present.

Glyphosate in water

Pesticide contamination in water is a serious issue. Ireland has strict rules and in 2020, 36 pesticide exceedances occurred at least once in public water supplies.

Over half (57%) of these were caused by MCPA, while 2-4D and glyphosate accounted for 12% each.

Areas which were highlighted for action for these exceedances were in Limerick, Longford, Cavan, Wexford and Mayo.

Contamination of waterways with pesticides needs to stop. The foil seal alone from a container can pollute 30km of a stream. It is also important to adhere to buffer zones and avoid drift into waterways.

What the EFSA says

While the European Food Safety Authority (EFSA) will publish a new report at the end of this consultation, its previous report stated that the toxicity of glyphosate needs to be redefined. It set new levels for operator exposure and consumers. It did not propose to classify glyphosate as carcinogenic.

The International Agency for Research on Cancer (IARC) said that glyphosate was genotoxic and would “probably” cause cancer in humans.

The EFSA stated: “The IARC report looked at both glyphosate – an active substance – and glyphosate-based formulations, grouping all formulations regardless of their composition. The EU assessment only considered glyphosate.

“This is because the EU and IARC take different approaches to the classification of chemicals. The EU assesses each individual chemical and each marketed mixture separately. The IARC assesses generic agents, including groups of related chemicals, as well as occupational or environmental exposure, and cultural or behavioural practices.

“This is important because although some studies suggest that certain glyphosate-based formulations may be genotoxic (ie damaging to DNA), others that look solely at the active substance glyphosate do not show this effect. It is likely, therefore, that the genotoxic effects observed in some glyphosate-based formulations are related to the other constituents or co-formulants”.

Certain glyphosate-based formulations display higher toxicity than that of the active ingredient, presumably because of the presence of co-formulants.

EFSA proposes that the toxicity of each pesticide formulation and its genotoxic potential should be further considered and addressed by member state authorities while they re-assess uses of glyphosate-based formulations in their own territories.

“This distinction between active substance and pesticide formulation mainly explains the differences in how EFSA and IARC weighed the available data. For the EU assessment, studies conducted with glyphosate were more relevant than studies conducted with formulated products containing other constituents, particularly when the other constituents could not be clearly identified.

Court cases

In recent times, there have been a number of court cases in relation to glyphosate in the US.

In August 2021, Bayer lost its third appeal in the US courts. Bayer was found responsible for a couple’s cancer after using glyphosate-based Roundup. The case in California was in the appeals court and the verdict was $86m.

It has been reported that Bayer has set aside billions of dollars for settlements and litigation and that there may be plans to replace glyphosate in weed killers in the US residential market with other active ingredients.

2017

Glyphosate was approved for use for five years by the European Commission.

May 2019

The European Commission appointed four member states including France, Hungary, the Netherlands and Sweden, acting jointly, to be rapporteurs for the next assessment of glyphosate and known as the Assessment Group on Glyphosate (AGG).

December 2019

The Glyphosate Renewal Group (a group of companies that wants the registration renewed) applied for the renewal of approval for the use of glyphosate post-2022 on 12 December.

June 2020

The supplementary dossiers containing the required set of scientific studies and literature data were submitted by the Glyphosate Renewal Group.

June 2021

The AGG submitted its assessments to the EFSA and ECHA.

September 2021

The EFSA and ECHA launched public consultations on the reports delivered by the AGG. The consultation ended on 22 November 2021.

December 2021

Over 400 submissions were reported as part of the consultation.

The conclusion of a peer-review process and the AGG’s renewal assessment report will be analysed by the Commission, which will then put forward a renewal report and a draft regulation to the member states on whether the approval for glyphosate can be renewed.

There will then be discussions in the standing committee on plants, animals, food and feed before a vote by member states on the Commission’s proposal.