‘Super pest’ can survive winters

A new strain of the diamondback moth (DBM) which is resistant to common plant protection has also become capable of surviving UK winters.

The latest research shows the moth has been found overwintering on swede crops grown under insect netting.

The caterpillars of DBMs feed on crops including cabbage, broccoli, swedes and Brussels sprouts, causing cosmetic damage which could result in a total crop loss.

Growers have now been being asked to submit samples of the DBM when seen through winter, or in spring when numbers rise, to help with monitoring and development of control strategies.

AHDB knowledge exchange manager Dr Dawn Teverson said brassica growers should be aware of the pyrethroid resistance. She added: “If pyrethroids are used, not only does this now fail to control DBM but it could also kill beneficial insect predators which would naturally help control the pest, exacerbating the problem.”

The diamondback moth is often described as a ‘super-pest’ because it has a rapid lifecycle, providing more opportunities for resistance to develop through gene mutation.

Last year Rothamsted Research tested three diamondback moth samples from Scotland, Lincolnshire, and Suffolk, and all were found to be resistant to pyrethroids.

Growing cause for concern: the diamondback moth.