AFP compared Brussels rules with those in Brazil to illustrate the differences in pesticide standards between the two blocs, which traded more than EUR15 billion worth of agricultural goods in 2024.

Brazil accounts for 80 percent of the EU's trade with Mercosur countries (Brazil, Argentina, Paraguay, Uruguay).

As of late November, it had authorised the use of 330 active substances.

Sixty percent of them had not been approved in the EU, 37 percent had been approved, and 3 percent were under review, according to data cross-checked between the Brazilian health regulatory agency (Anvisa) and the European Commission.

Conversely, of the 421 active substances approved in the EU, 73 percent had not been greenlighted in Brazil.

However, these figures come with caveats.

EU member states can temporarily allow national use of substances banned at the European level.

In France, for instance, the herbicide flufenacet -- classified as an endocrine disruptor and withdrawn from the EU market in December -- has been granted a grace period allowing one more year of use.

A country may also ban a substance authorised by Brussels if it deems the environmental or health risks are too high.

Acetamiprid, a neonicotinoid highly toxic to bees, is currently banned in France but allowed elsewhere in the EU.

- Residues -

Although imports from Mercosur must legally meet EU standards, European farmers argue that controls are too weak to prevent unfair competition.

Critics of the EU-Mercosur deal point in particular to the EU's tolerance of pesticide residues below defined safety limits, even though the substances themselves are banned in the EU.

In response, the European Commission pledged in early January to completely ban imports containing residues of three fungicides: carbendazim, benomyl and thiophanate-methyl.

The first two are already banned in Brazil, but thiophanate-methyl -- withdrawn from the EU market in 2021 over health concerns -- remains authorised in the Latin American state.

Some countries have gone a step further. France has suspended imports of products containing residues of mancozeb and glufosinate, in addition to the three fungicides targeted by Brussels.

Mancozeb, used on avocados, mangoes and peppers, is classified as an endocrine disruptor by the European Food Safety Authority (EFSA), and is suspected of reproductive toxicity and carcinogenicity, according to the European Chemicals Agency (ECHA).

Glufosinate ammonium, an herbicide widely used on potatoes, is also classified for presumed human reproductive toxicity.

Banned in the EU, these substances rank among the best-selling in Brazil: mancozeb is the second most marketed active ingredient, glufosinate the sixth.

- Banned in Europe, exported to Mercosur -

European chemicals companies have historically manufactured such pesticides and shipped them to Mercosur countries.

In 2024, groups like BASF, Corteva, Syngenta and Bayer exported 18,000 tonnes of pesticides prohibited for use within the EU, according to data compiled by Swiss NGO Public Eye and Greenpeace UK's investigation unit Unearthed, drawing from the ECHA and national authorities.

More than 80 percent of these exports went to Brazil, the world's second-largest market for these EU-made pesticides after the United States.

Leading the list was picoxystrobin, a fungicide used on cereals and soybeans, banned in the EU since 2017 over genotoxic and environmental risks.

Soybeans -- of which Brazil is the world's top exporter -- reach the EU mainly as soybean meal to feed livestock. In 2024-25, Europe imported over 20 million tonnes of Brazilian soybean meal.

Regarding the substances targeted by Brussels and Paris last week, European companies filed export notifications for 2,300 tonnes of glufosinate, 260 tonnes of thiophanate-methyl and 250 tonnes of mancozeb to Mercosur in 2024, according to figures published in September 2025.

Several environmental NGOs hit out at the EU for what they called a "double-standard policy" that bans certain pesticides in Europe while exporting them abroad.