Resistance to commonly-used pyrethroid insecticides is now being found in adult pea and bean weevils, which are an increasingly damaging pest of pulse crops.

Steve Foster at Rothamsted Research has found adult weevil resistance to these insecticides after reports of failure to control the weevils in field crops.

See also: Weevil attacks rise in pea and bean crops after warm weather 

Dr Foster tested samples collected from Hertfordshire, Lincolnshire, Northamptonshire, Nottinghamshire and Warwickshire, and found they contained adult weevils which were resistant to a representative pyrethroid when applied at a field dose.

“The next step is to find and understand the cause of this resistance, which is likely to exist in other pyrethroid insecticides used,” he said.

“In the meantime, growers should be aware that treatment with these compounds against this pest may not be effective,” Dr Foster added in a statement.