They have divided opinions around countless Christmas dinner tables – but those who love their Brussels fear a festive shortfall after the damage done by a summer invasion of sprout-loving caterpillars.

Eastern Daily Press: The caterpillar of the diamondback moth. Picture: Mark MallottThe caterpillar of the diamondback moth. Picture: Mark Mallott (Image: Mark Mallott)

Growers have seen many sprout stalks devastated by caterpillars of the diamondback moth, a pest which has plagued many East Anglian farms this year.

Some of the nation's largest producers have thrown away huge quantities of damaged sprouts, with some farmers in Lincolnshire – which supplies almost two thirds of the UK crop – reporting losses of up to 60pc.

However, supermarkets have reassured shoppers that there will still be enough British sprouts to go around to fulfil festive demand.

Charlie Tacon, who grows sprouts in Rollesby, near Great Yarmouth, for farm shops and supermarkets, said he had been battling the pest all summer, but had found ways to limit his losses to about 5-10pc.

Eastern Daily Press: Christmas dinner. Picture: Matthew UsherChristmas dinner. Picture: Matthew Usher (Image: Archant © 2008)

'It was in April and May that we first started seeing these moths in the yard,' he said. 'When we were told this could be an issue we invested in some very fine netting to go over the veg to keep the bugs out. But as the sprout stalks got taller it lifted the cover and we got damage around the edges. It looked like it had been shredded.

'The caterpillar is a tiny little thing, but it drills into the middle of the plant, whereas other caterpillars tend to eat around the edges.

'They bury themselves in the foliage and they are resistant to a lot of our pesticides, so they are very difficult to get rid of.

'The worst period was May to July, in the warmest months. We were spraying every week, and using different mixtures to get them at different growth stages.

'Most of the damage for us was before the sprouts came out, and we were able to do something about it. Thankfully we had the netting too so we probably only lost 5-10pc around the edges.'

Despite the problems for growers, supermarkets have said they don't expect there to be any significant issues with sprout supplies this year.

Roger Grosvenor, joint chief executive for the East of England Co-op, added: 'We are currently working closely with our suppliers to source high quality sprouts to our members and customers throughout the Christmas period.'

DIAMONDBACK MOTHS

Diamondback moths, also known as cabbage moths, originate in the Mediterranean and in their caterpillar form they can devastate crops including Brussels sprouts, cauliflowers, kale, and broccoli.

The species is often described as a 'super-pest' because it has a rapid lifecycle and has been found to be resistant to some insecticides.

Dr Rosemary Collier, who manages the Pest Bulletin funded by the AHDB's (Agriculture and Horticulture Development Board's) horticulture division, said: 'At the end of May this year, very large numbers of diamondback moths arrived in the UK, the largest influx for 20 years. They continued to arrive over several days and could be found throughout the country. The moths laid eggs on a range of brassica crops and some were badly affected.'

Although other insecticides were available, control options were becoming limited and AHDB Horticulture secured a temporary emergency approval for a new insecticide Benevia,

In August, resistance to commonly-used pyrethroid pesticides was confirmed in Lincolnshire, and the AHDB worked with the farming industry to secure an emergency 120-day authorisation for a new insecticide, called Benevia, for use on a range of brassica crops for diamondback moth control.

The AHDB will hold a diamondback moth workshop for farmers on January 24 in Peterborough. For more information and bookings, click here.