Boom in diamondback moth numbers could damage crops in Norfolk and across the UK

Diamondback moth_Picture.Rothamsted Research.

Diamondback moth_Picture.Rothamsted Research. - Credit: Archant

It might not look like the most menacing of threats, but this tiny creature is causing mounting concern among scientists and farmers.

Experts have warned that the country is experiencing the biggest boom in 20 years of diamondback moths arriving from continental Europe.

The insects feed on 'cruciferous' crops - such as cabbage, cauliflower and broccoli- and has been labelled a 'super pest', as it is resistant to several insecticides.

According to reports, tens of millions of the insects have come to the UK in the past week - 100 times the number that arrive in the entire year.

The Norfolk Moths group reported that several million swarmed to the county in the first week of June.


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An alert has been issued by researchers at the Rothamsted Research in Harpenden in Hertfordshire.

Chris Shortall, research scientist and coordinator of the Rothamsted light-trap network said the insect could have been bought in from far eastern Europe or Russia, with the easterly winds experienced last month.

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He said the mild winter weather conditions in eastern Europe may have meant more of the moths survived and may have even bred through the cold months.

Mr Shortall said: 'In our light-traps here at Rothamsted we have seen in two nights the number of diamondback moths that we usually record in a year, and this is reflected elsewhere in the network.'

Alexander Margerison-Smith, from Lankfer Produce Ltd, a broccoli and cauliflower producer in the Wisbech area, said: 'We are keeping a close eye on it and monitoring the situation closely. It is abnormal and the numbers are a lot higher than usual.'

David Norman, an agronomist who works in west Norfolk and Cambridgeshire, said the moths themselves were not the problem, but the caterpillars they produce would be.

'There are huge numbers about. We have been seeing them for a couple of weeks but more in the last week or so. The expectation is that this lot will produce another generation by another four to six weeks' time so we will probably see even more,' he said.

He added they boom in numbers could mean a 'big crop loss' if the pest could not be controlled.

Do you have a farming story? Email chris.hill@archant.co.uk

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