Sugar beet growers will have access to seed treated with neonicotinoids this growing season, as scientists have predicted a serious risk of virus yellows infection, based on a burgeoning aphid population.

Defra passed the conditional emergency authorisation to use Cruiser SB, which contains the active substance thiamethoxam, in January.

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But this was subject to the predicted risk of virus yellows infection in the national sugar beet crop, based on the Rothamsted model, exceeding 65%.

Latest data from the British Beet Research Organisation (BBRO) actually puts that risk at 83% in the absence of any disease controls, triggering the emergency authorisation for a third consecutive year.

Mild February

“This is almost entirely due to how mild it has been in February,” said Mark Stevens, head of science at BBRO.

“Last year, the risk was put at 67.5%, with aphids predicted to start flying on 22 April. This year, it is at 83%, with first aphids expected to fly on 10 April.

“We are hearing reports of overwintered adult aphids being found in fields right now. It is clear a significant population has survived the wind and the rain.”

Grower response

The move to sanction the use of Cruiser SB on beet seed has been welcomed by grower representatives.

NFU Sugar board chairman Michael Sly said it was clear that beet growers are facing a significant threat from virus yellows disease this year.

“The emergency authorisation for growers to use the neonicotinoid seed treatment in a safe, limited and controlled way gives them a crucial tool to help manage the aphids which spread the disease and can decimate crops,” he said.

“In recent years, virus yellows disease caused up to 80% yield loss in the UK sugar beet crop, an industry that safeguards more than 9,500 jobs, so growers will be very relieved to have the option to use this treatment.”

Solutions

Mr Sly stressed that the whole industry, led by the BBRO, was working hard to find viable, long-term solutions to this disease.

British Sugar recently secured £660,000 from the government’s Farming Futures R&D fund to look at how gene editing can be used to develop natural virus yellows resistance in sugar beet.