About Us

The Phosphite Biostimulant Stewardship Group (PBSG) was created in 2020 by a group of like-minded biostimulant manufacturers to promote the continued use of phosphite as a biostimulant, enabling subsequent EU registration under biostimulant regulations.

The EC Fertilising Products Regulation (FPR – EU 2019/1009) was implemented in 2022, and for the first time included plant biostimulants. However, disappointingly for phosphite users, this established biostimulant substance was excluded from the regulation.

For the last five years, the PBSG has worked closely with other organisations such as EBIC (The European Biostimulants Industry Council) and the Residue Data Consortium to persuade regulators to include phosphite as a plant biostimulant. The PBSG remains committed to this valuable product which is proven to significantly improve nutrient use efficiency, yields and quality across a wide range of crops.

Our position is that phosphite has a scientifically proven mode of action and has been demonstrated over many years to be an effective biostimulant with an important agronomic input across a wide range of crops in European countries. Phosphite is now one of the most researched and consistently performing biostimulants on the market today and should continue to be accessible to growers in the future.

The PBSG is funded by its members. For more information on our work or to provide support for our aims, please contact us.

Latest Update

In May 2025, at the European Commission Expert Group on Fertilising Products, EBIC presented finalist updated proposal for the inclusion of phosphite in the regulations for plant biostimulants in response to a discussion item first tabled in October 2022 by the Fertilising Products team at the Directorate General for the Internal Market, Industry, Entrepreneurship and SMEs(DG GROW). The Commission discussion item noted the growing body of scientific evidence of legitimate biostimulant uses of phosphites and proposed preliminary language for an amendment to the FPR to allow phosphites to be used in EU Plant Biostimulants.

Member states now have until 30 June 2025 to provide written comments.

Next Steps

EBIC continues to work with DG GROW and DG SANTE to facilitate this process and establish the multiple-use principle which acknowledges that components may used in substances with different functions, for example plant biostimulants and crop protection products.

A group of 11 phosphite plant biostimulant manufacturers, predominantly PBSG and EBIC members, has committed to fund the first stage of forming a residue consortium to address Member State concerns about how plant biostimulants and fungicides containing phosphite can co-exist within current residue regulations. Barkwith Associates have been commissioned to consult with the Commission and the rapporteur member state (Spain) to establish the most practicable and economically viable means of achieving this.

If you are interested in supporting our aims, contact us.

News

Proposal for FPR inclusion presented to EC Expert Group

27 May 2025

EBIC proposed adding phosphite to plant biostimulant regulations at the May EU Commission meeting, following a 2022 DG GROW discussion.

Phosphite biostimulant efficacy confirmed for 6th consecutive year

31 March 2024

Data released by the Phosphite Biostimulant Stewardship Group (PBSG) using aggregated, anonymised trials results.

Phosphite research confirms biostimulant function

31 October 2022

The PBSG-funded research into the mode of action of phosphite has been published in the scientific journal Frontiers in Plant Science.

Phosphite seed treatment an obvious choice for UK growers

23 September 2022

Farmers across the UK are confirming their cropping plans for next season with a raft of seed orders recently placed.

Arable yields up 7.6% with phosphite plant biostimulants

17 August 2022

New data from trials of phosphite biostimulants in arable crops demonstrates a consistent yield improvement of over 5% against untreated controls.

Phosphite trials continue to prove efficacy

18 July 2022

Members of the PBSG have updated their aggregated trials data with results from 2021 trials, providing further evidence of the efficacy of phosphite as a biostimulant.

Farmers save on nitrogen costs by using phosphite as a plant biostimulant

23rd November 2021

As nitrogen prices continue to rise, farmers who used phosphite seed treatment on their autumn-sown crops have cause to feel pleased.

Phosphite as a biostimulant saves up to 40kg per hectare of applied nitrogen

25th October 2021

Research by the Universities of Nottingham and Kiel has shown that the use of phosphite as a biostimulant has a dramatic effect on the uptake and efficient use of nitrogen, saving up to 40kg/ha from leaching or volatilisation.

Trials data prove the economic benefit of phosphite as a biostimulant

29 September 2021

The economic case for the use of phosphite as a biostimulant has been clearly demonstrated using data from 178 individual trials undertaken in eight crops over the last four years.

Phosphite biostimulants a proven choice to give crops their best start

31 August 2021

The Phosphite Biostimulant Stewardship Group (PBSG) has released data from trials that prove the agronomic benefits of using phosphite as a biostimulant.

The impact of phosphite on carbon gain and plant physiology

27 November 2020

The latest output from the University of Nottingham’s research into phosphite as a biostimulant shows gains in a number of physiological processes.

Gene expression and hormone profiling efforts to understand phosphite mode of action

18 November 2020

Scientists at the Universities of Nottingham are focusing on hormone analysis and gene expression to further understand and explain the biostimulant action of phosphite.

Heat treatment experiments assess the role of phosphite in moderating heat stress

9 November 2020

Scientists at the University of Nottingham are investigating the effect of phosphite treatment on heat stressed wheat plants.

Field trials show phosphite increases crown root length

28 October 2020

Preliminary results from field experiments carried out by Omex Agriculture and the University of Nottingham demonstrate improvements in crown root length and canopy cover in wheat plants treated with phosphite.

Confirmation of the biostimulant properties of phosphites

24 June 2020

A White Paper, published by the School of Biosciences at the University of Nottingham, confirms the biostimulant properties of phosphites and the part they play in root development and nutrient use efficiency.

Technical Information

Phosphite is a well-established, cost effective, proven technology used by farmers across Europe for many years on a wide range of crops.

The PBSG collaborated with the University of Nottingham and the Biotechnology and Biological Sciences Research Council (BBSRC) to prove the mode of action of phosphite as a biostimulant. Its peer-reviewed research into the biostimulant function of phosphite was published in the scientific journal, Frontiers in Plant Science.

Phosphite, used in a biostimulant, encourages root development and improves nitrogen assimilation. It can be applied as a seed treatment or a foliar application and is readily absorbed and translocated to the roots.

Tests on two key agricultural crops, wheat and oilseed rape, showed that phosphite treatment improves the crop’s nitrogen use efficiency (NUE) which has a positive impact on yield (Verreet (2019) top agrar 8/2019, 56-60).

The effects of phosphite appears to be more pronounced under stress conditions (Mohammed et al (2019) 4th Biostimulant Congress, Barcelona).

The research showed that phosphite, when applied at low doses, provides a low input, cost-effective way to enhance root architecture. Tested across a range of crops, biomass typically increased by 30%. Kiel University has identified a strong economic case for phosphites as biostimulants, with treatment improving both yield and farm income.

More details of research into the use of phosphite as a biostimulant can be found in the University of Nottingham White Paper and the University of Kiel White Paper.

Economic evidence of the value of phosphite, including aggregated trials data from PBSG members which demonstrates the contribution phosphite makes to agricultural productivity, can be found in our news section.