Pyrethroid sensitivity in UK cereal aphids (2019–20)

Aim

The aim of the project was to test samples of two cereal aphid species for their sensitivity to pyrethroids.

Background

Earlier work (114R480) showed that some grain aphids have a gene mutation that confers knockdown resistance (kdr) to pyrethroids.

As the mutation is well understood, it is possible to screen aphids, collected from the suction trap network, to provide a good picture of the proportion that carry kdr resistance.

However, it is possible that aphids may develop resistance via other resistance mechanisms – which would not be picked up by screens for kdr.

Therefore, live aphids were collected from crops and tested using an alternative bioassay method.

Results

With the grain aphid (5 samples screened), there is no evidence of the development of pyrethroid resistance above and beyond that already known in this pest.

As much less is known about pyrethroid sensitivity bird cherry-oat aphid, a larger number of samples were screened (21). All the samples showed bioassay responses similar to those seen in pyrethroid-susceptible bird cherry-oat aphids. Therefore, this project found no evidence of the development of pyrethroid resistance in this pest.