Growersare being asked to send suspected pyrethroid-resistant cabbage stem flea beetle(CSFB) samples this harvest to Rothamsted Research for resistance analysis.
Followinglast years restriction, oilseed rape (OSR) seed treated with neonicotinoidscannot be planted this autumn and foliar-applied pyrethroids will now be themain treatment option to protect OSR during the first 6-8 weeks of growth fromCSFB attack.
Followingreports of knock-down resistance (kdr) to pyrethroids in CSFB in Germany andsuggestions from UK growers that pyrethroids are failing against CSFB in theUK, HGCA has commissioned research to investigate the issue.
Aspart of this work, Rothamsted Research is calling for growers to send CSFBpopulations, where resistance is suspected, to them for analysis to help detectany potential resistance issues in the UK.
DrStephen Foster of Rothamsted Research said: We are looking to see if the kdrmutation is present in UK CSFB populations and, assuming it is, we will thenwork to quantify resistance levels.
As weneed good samples with a high number of live beetles, we are asking growers tosample around harvest because beetles are found in large numbers at this time.
To helpgrowers, we have produced some simple sampling guidelines which are availablefrom the HGCA website.
Withmany more growers considering pyrethroid applications this autumn as aconsequence of the neonicotinoid restriction, it is essential that we all worktogether to understand and manage any potential resistance threat.
The CSFBresistance project is part of a package of research commissioned by HGCA inresponse to the restrictions.
CarolineNicholls, HGCA Research and KT Manager, said: We have also asked RothamstedResearch to develop a laboratory assay to test the potential of peachpotatoaphids to transmit turnip yellows virus (TuYV), in addition to screens alreadyunderway to detect known insecticide resistance mechanisms.
We havealso funded ADAS to investigate how much shot hole damage OSR seedlings cantolerate so we can make sure growers are working with the best spray thresholdsfor CSFB.
Wherepossible, results from our research will be made available in time to helpgrowers adapt their pest control strategies for OSR this autumn.