Emergency beet moth approval granted as sugar beet risk rises

Sugar beet growers have been handed emergency access to a key treatment for beet moth as rising pest pressure and drought stress threaten the 2026 crop.

NFU Sugar, working with British Sugar and with technical support from the British Beet Research Organisation, has secured emergency authorisation for the use of Coragen, also known as chlorantraniliprole.

The approval permits a single application for beet moth control between 3 June and 30 September 2026.

The move follows reports of six-figure losses from beet moth infestations in 2025, with increased numbers already trapped or detected this season.

Beet moth, or Scrobipalpa ocellatella, is not usually considered a regular pest in the UK and is more commonly associated with warmer and drier regions, including Mediterranean areas, Eastern Europe and parts of Asia.

However, hotter and drier conditions in the UK have helped populations reproduce and spread in recent years.

The caterpillars can mine into the stems and crowns of sugar beet plants, causing damage to the heart of the crop.

As in 2025, drought stress is adding to concerns for this year’s crop, with dry conditions leaving crowns more exposed.

This gives moths more opportunity to lay eggs and caterpillars more chance to burrow into plants.

NFU Sugar said growers using Coragen must record where and when it is applied, the number of hectares treated, the percentage of crop affected and the fate of treated beet tops.

Tops from Coragen-treated sugar beet must not be fed to, or grazed by, livestock.

After the authorisation period ends, growers will be required to confirm through My British Sugar whether Coragen was used.

The information will be passed to the regulator as evidence of industry compliance, which NFU Sugar said would be essential to support any future emergency authorisation applications.

Full details of the approval, including terms of use and stewardship requirements, are available on the BBRO website.

Growers are being urged to check crops closely and treat with Coragen at the first signs of damage, inspecting the heart leaves of multiple plants for signs of infestation.

These include feeding damage to the petioles of emerging leaves, black frass on the heart leaves, or silk spun by larvae.

High water volumes are required to help the active ingredient reach the target caterpillars by penetrating the crop canopy.

The BBRO is currently advising against the use of pyrethroids for caterpillar control because of sustained high aphid pressure.

The warning is aimed at avoiding harm to beneficial insects.

Growers can access the latest beet moth monitoring data through the CropWatch section of the BBRO website, alongside updated guidance and information.

NFU Sugar Board chair Kit Papworth said beet moth was adding to the pressure already facing the homegrown sugar beet sector.

“Beet moth represents the latest troubling addition to the broad complex of pest and disease pressures facing the homegrown sugar beet crop,” he said.

He said many growers were already dealing with severe infestation this season.

“With many growers already suffering from severe infestation in 2026, we welcome the decision to grant emergency authorisation for the use of Coragen this growing season,” he added.

Mr Papworth said the BBRO was leading work to better understand the pest and develop effective ways to reduce the threat it poses.

“Looking forward, I urge government to work with industry to ensure the availability of viable controls in future seasons,” he said.

The authorisation gives growers a short-term control option, but the industry is now looking for longer-term answers as beet moth becomes a growing threat to the UK sugar beet crop.