This autumn, adult cabbage stem flea beetle (CSFB)will be monitored on winter oilseed rape (WOSR) crops for a second yearrunning.
Last autumn, AHDB-funded monitoring work providedthe first national snapshot of the damage caused by CSFB in the wake of theneonicotinoid seed treatment restrictions.
The findings, based on the assessment period 2229 September 2014,found that CSFB damage contributed to estimated losses of 2.7% of the WOSR areain England and Scotland, with the worst affected areas being the South East andEastern regions.
Latest CSFB monitoring plans
Caroline Nicholls, AHDB Research Manager, said:Autumn 2015 marks the second season where neonicotinoid seed treatments willnot be available for the vast majority of oilseed rape crops.
As it is essential that we develop ourunderstanding of the impact of this pest across seasons, we decided to investin monitoring once again.
As in 2014, the work will be led by ADAS incollaboration with AICC to provide an estimate of the incidence and severity ofadult CSFB damage in WOSR.
Based on information provided by a network ofcounty-level independent agronomists, the work will assess the impact acrossthe UK, including counties with and without access to neonicotinoid seedtreatments.
Unlike 2014, where crops were assessed over aseven-day period, the latest monitoring effort will be linked to crop growthstages.
The growth stages selected to focus the monitoringefforts are based on those used for the current adult CSFB spray thresholds:
> Cotyledon2 true leaf growth stage
> 34 true leaf growth stage
Linking the monitoring period to crop growth stagewill provide us with a much clearer picture of damage, as nationwide monitoringwill be conducted over a much longer period compared to 2014, stated MissNicholls.
Information on redrilling, insecticide applicationsand resistance, as well as crop condition will also be recorded as part of thework.
The monitoring forms part of AHDB Cereals &Oilseeds portfolio of activity to provide independent information on theimpact of the neonicotinoid seed treatment restrictions.
Previous impact results
The latest announcement follows pot-experimentresults published by AHDB in August showing that once winter oilseed rape (WOSR) has passed through thecritical emergence phase, it can cope with relatively severe defoliation.
Last September, AHDB also showed that resistance to pyrethroids in CSFB was widespread inEngland.
To limit the spread of resistance, growers who haveused a pyrethroid spray but have experienced poor control are being remindednot to use a pyrethroid-based product again.