Ethephon: growth regulator in focus

Extended EU approval and versatile applications in agriculture

Feb 2025. Ethephon is a synthetic plant protection active ingredient primarily used as a growth regulator in agriculture. The active ingredient is known for its ability to release ethylene, a natural plant hormone that regulates important physiological processes in plants. We give you an overview of the use of ethephon, as well as the current approval status in the EU.

Use of ethephon

Ethephon is used in a variety of crops, including cereals, fruits, vegetables, and ornamental plants. Its main applications include:

Promoting fruit ripening and colour development: e.g., in apples or tomatoes
Improving harvest efficiency: such as loosening berries in grapes
Growth regulation: to limit stem elongation in cereals and increase lodging resistance

Regulatory status

The European Commission has extended the approval of the active substance ethephon in the European Union until 31 January 2039. The corresponding Implementing Regulation (EU) 2023/2591 was published on 22 November 2023 and has been in effect since 1 February 2024. The previous restriction on its use solely as a growth regulator has been lifted. However, certain conditions must be taken into account when approving plant protection products containing ethephon^[1].

Currently, the Acceptable Daily Intake (ADI) for ethephon is 0.03 mg/kg body weight per day, and the Acute Reference Dose (ARfD) is 0.05 mg/kg body weight^[2].

Detection of phosphonic acid after ethephon application?

The chemical name of ethephon (C₂H₆ClO₃P) is 2-chloroethylphosphonic acid. The chemical degradation primarily occurs through hydrolysis, breaking down into ethylene (C₂H₄), phosphoric acid (H₃PO₄), and hydrogen chloride (HCl). In soil and plants, a potential degradation into phosphonic acid has also been suggested. Additionally, there are indications that small amounts of phosphonic acid may be present in ethephon formulations.

If plants or plant products are analysed for phosphonic acid, a positive result could be due to a previous ethephon application. However, no conclusive practical data confirm this. Theoretically, such a finding could be mistakenly interpreted as evidence of phosphonate or phosphite use, as all these substances share phosphonic acid as a common degradation product. Further research also indicates that phosphonic acid occurs naturally in the environment^[3].

To avoid misinterpretation, it is essential to consider the application history and examine further indicators of potential ethephon use. This is particularly important to determine whether phosphonic acid residues originate from phosphite fertilisers rather than from ethephon.

We support you

The Eurofins Food & Feed Testing laboratories in Germany have many years of experience in ethephon analysis in plant-based foods. We are happy to assist you with any analytical inquiries. For support, please contact your personal account manager or reach out to our experts Ayman Farhod Naeem and Jeannine Rüdiger.

Sources

[1] Commission Implementing Regulation (EU) 2023/2591 renewing the approval of the active substance ethephon in accordance with Regulation (EC) No 1107/2009;
Regulation (EC) No 1107/2009 concerning the placing of plant protection products on the market (consolidated text)
[2] European Commission, EU Pesticides database, Active sustance: Etephon
[3] Nader, W., Zahm, A. & Jaschik, J. (2023). Phosphonic acid in plant-based food and feed products – Where does it come from? Food Control, 150, 109701. https://doi.org/10.1016/j.foodcont.2023.109701