Copper as a fungicide in agriculture: health, environmental and socio-economic challenges

Copper: an authorised substance with points that require attention

Copper compounds (copper hydroxide, copper oxychloride and tribasic copper sulphate) have fungicidal and bactericidal properties that have been exploited with the Bordeaux mixture since the 19th century. Copper is widely used as an active substance in agriculture to combat certain plant diseases, particularly blight.

Re-approved in Europe since January 2019, copper compounds are used as ingredients in many plant protection products. Their marketing is subject to national MAs. In France, ANSES issues these authorisations.

Due to the toxic properties of copper compounds for humans and the environment, the 2018 approval regulation set out some points that require attention in terms of risks to certain workers and limits the quantities that can be applied per hectare.

Since 2025, copper compounds have also been classified as substances that are candidates for substitution under Regulation (EC) No 1107/2009, due to their persistence in soil and their toxicity to aquatic organisms. This means that an agricultural use of copper may not be authorised if safer alternatives with similar efficacy are available.

ANSES took all these considerations into account in its assessments of copper-containing products.

MAs that authorise the main agricultural uses, with enhanced protective measures

Following the re-approval of copper compounds applicable as of 01/01/2019, ANSES reviewed MA applications submitted in France by manufacturers of plant protection products for a wide range of agricultural uses.

To take account of health and environmental risks, with specific points of concern for copper, ANSES:

• carried out the mandatory comparative assessment for this “candidate for substitution” substance: in light of the available treatment alternatives, the Agency concluded that substitution was possible for the treatment of tomato late blight under shelter, regardless of the type of production sector.
• analysed possible risk management measures by reviewing the authorisation conditions already explore in other Member States, then sought the opinion of the Marketing Authorisations Monitoring Committee (CSAMM) with regard to the impact and feasibility of the risk control measures that the Agency was considering for its MA decisions.

In July 2025, ANSES issued its conclusions for 34 copper-containing products. Overall, all the main uses of copper are covered by the authorisations issued by the Agency, although uses of certain products have been denied authorisation due to non-compliance with the legal requirements (e.g. for residue levels).

These authorisations impose stricter conditions of use, in particular with measures to limit occupational exposure and water and soil contamination. In some cases, additional data will have to be provided by the manufacturers to be able to rule on specific risks to birds and mammals.

Significant socio-economic impacts when copper-containing treatments are not used

In 2020, copper ranked ninth among the most frequently sold active substances in agriculture in France. According to the report published by ANSES in 2022 on the mapping of uses of copper-containing plant protection products in France, the importance of copper for plant protection varies depending on the crop and production method. It is particularly critical in organic agriculture. Although the total tonnages used are lower in organic agriculture, the dose applied per hectare is often higher than in conventional agriculture.

Prior to the next European re-assessment of the active substance, to anticipate the effects of new changes for agricultural sectors, ANSES issued an internal request to analyse the socio-economic impacts of a possible restriction or even ban on copper-containing plant protection products in France, in both conventional and organic agriculture.

This expert appraisal was carried out with the support of the Agency’s Expert Committee on Socio-economic analysis. It used a forward-looking approach based on a different method and broader data than those used for the comparative assessment of substitution possibilities conducted during its review of MA applications for products.

ANSES assessed scenarios for reducing or eliminating the use of copper in the grapevine and apple sectors, in conventional and organic agriculture, and in the potato sector in organic agriculture. Some of these scenarios identified combinations of alternatives that generally had a more favourable environmental and health profile and that appeared technically – and sometimes economically – feasible. However, the availability of these alternatives is still often limited. Furthermore, for some sectors, they would require significant adaptation efforts and a costly transition in the short term.

Given the difficulty of replacing copper in the current agricultural model, particularly for organic crops, the socio-economic analysis conducted by ANSES concluded that it is necessary to explore more systemic agronomic approaches, instead of “alternative by alternative” substitution, in order to develop long-term viable copper reduction strategies. These approaches may focus on combinations of alternatives and even consider new production models.