Emergency bid to keep mancozeb fails, GB Potatoes confirms

Potato growers will head into the 2026 season without access to mancozeb after industry efforts to secure emergency approval for its continued use were halted.

GB Potatoes has confirmed it will not proceed with an Emergency Authorisation (EA) application for the fungicide, following technical discussions that concluded any approval would deliver little practical benefit for growers.

The decision follows the planned withdrawal of mancozeb from use in the UK at the end of the 2025 season, raising concerns over blight control at a time of increasing disease pressure and resistance risk.

GB Potatoes said it assessed all possible routes to support growers through the transition, including whether an EA could allow limited use of mancozeb on potato crops in 2026.

Scott Walker, chief executive of GB Potatoes, said the option was explored in detail. “Following the announcement that mancozeb would be withdrawn from use in the UK at the end of the 2025 season, GB Potatoes explored the feasibility of progressing an Emergency Authorisation (EA) application to allow a continued use on potato crops,” he said.

He said such an authorisation could have supported resistance management. “An EA permitting the use of mancozeb for the 2026 season, would have delivered a significant resistance management benefit at a time of increasing pressure from blight resistance,” he said.

A small technical group was brought together with support from Horticulture Crop Protection Ltd to develop a potential application and engage with the Health and Safety Executive (HSE) on approval requirements.

Pre-application discussions were also held with authorisation holder UPL, which GB Potatoes said were constructive.

However, the process identified a critical limitation. “It became clear that, in order to meet HSE risk assessment requirements, any authorisation would be limited to a single application of mancozeb per crop,” Mr Walker said.

He said this restriction made the proposal unworkable. “Such a restriction would not be commercially viable given the additional stewardship requirements that would need to be put in place,” he said.

Agronomists involved in the discussions also advised that the benefit would be minimal, concluding that “a single application would deliver only very limited resistance management benefit”.

As a result, GB Potatoes decided not to proceed. “With great disappointment, the decision was taken not to proceed with an Emergency Authorisation application for mancozeb,” Mr Walker said.

He said all possible avenues had been explored and thanked the HSE, Horticulture Crop Protection Ltd and a number of industry specialists for their time and input.

The outcome leaves growers preparing for the 2026 season without a fungicide that has played a long-standing role in resistance management, increasing reliance on remaining chemistry and alternative disease control strategies.