Growers of linseed seed in England have the opportunity to protect the quality and yield of their crops thanks to the emergency authorisation of a desiccant.

The withdrawal of diquat had left linseed seed producers with no chemical option for desiccation this harvest.

That’s because seed growers can’t use the alternative desiccant glyphosate, as it can affect germination and plant survival.

See also: Pros and cons of alternative breakcrops to OSR

But the AHDB announced on Friday (7 August) that it had secured a new emergency authorisation for Spotlight Plus (carfentrazone-ethyl).

The authorisation by the Chemicals Regulation Division follows discussion by the UK Expert Committee on Pesticides on 14 July.

Bolette Palle Neve, at the AHDB, said: “In linseed, the seed tends to ripen before the stems fully dry out, which can make the crop a challenge to cut.

“The UK weather is also not consistent enough for crops to be swathed and left to dry naturally, so chemical desiccation is an essential option.”

Premium Crops worked with the AHDB to secure the authorisation. Company agronomist Hannah Foxall said it was “critical”.

“The longer linseed remains in the field, the more vulnerable it becomes to several diseases. Crucially, diseased crops may fail to achieve the strict standards set for certified seed crops.”

Seed-borne disease threat

In the absence of an effective desiccant, the seed production area would need to rise to offset failure rates, which could be as high as 50%, due to seed-borne diseases. Such additional investment in seed production could add as much as 10-20% to the price of certified linseed, according to estimates.

Most linseed is combined shortly after wheat in late August/early September. The authorisation ends on 23 September 2020.

Growers can apply for emergency use of carfentrazone-ethyl (PDF). Applications will be considered separately for growers in Wales, Scotland and Northern Ireland, as devolved administrations will need to vote independently on whether to permit the emergency use.

The original application also requested the use of carfentrazone  on main-crop linseed, but this was not granted because of the availability of the alternative glyphosate.