This autumn, adult cabbage stem flea beetle (CSFB) will be monitored on winter oilseed rape (WOSR) crops for a second year running.

Last autumn, AHDB-funded monitoring work provided the first national snapshot of the damage caused by CSFB in the wake of the neonicotinoid seed treatment restrictions.

The findings, based on the assessment period 22–29 September 2014, found that CSFB damage contributed to estimated losses of 2.7% of the WOSR area in England and Scotland, with the worst affected areas being the South East and Eastern regions.

Latest CSFB monitoring plans

Caroline Nicholls, AHDB Research Manager, said: “Autumn 2015 marks the second season where neonicotinoid seed treatments will not be available for the vast majority of oilseed rape crops.

“As it is essential that we develop our understanding of the impact of this pest across seasons, we decided to invest in monitoring once again.”

As in 2014, the work will be led by ADAS in collaboration with AICC to provide an estimate of the incidence and severity of adult CSFB damage in WOSR.

Based on information provided by a network of county-level independent agronomists, the work will assess the impact across the UK, including counties with and without access to neonicotinoid seed treatments.

Unlike 2014, where crops were assessed over a seven-day period, the latest monitoring effort will be linked to crop growth stages.

The growth stages selected to focus the monitoring efforts are based on those used for the current adult CSFB spray thresholds:

> Cotyledon–2 true leaf growth stage

> 3–4 true leaf growth stage

“Linking the monitoring period to crop growth stage will provide us with a much clearer picture of damage, as nationwide monitoring will be conducted over a much longer period compared to 2014,” stated Miss Nicholls.

Information on redrilling, insecticide applications and resistance, as well as crop condition will also be recorded as part of the work.

The monitoring forms part of AHDB Cereals & Oilseeds’ portfolio of activity to provide independent information on the impact of the neonicotinoid seed treatment restrictions.

Previous impact results

The latest announcement follows pot-experiment results published by AHDB in August showing that once winter oilseed rape (WOSR) has passed through the critical emergence phase, it can cope with relatively severe defoliation.

Last September, AHDB also showed that resistance to pyrethroids in CSFB was widespread in England.

To limit the spread of resistance, growers who have used a pyrethroid spray but have experienced poor control are being reminded not to use a pyrethroid-based product again.

For full information on AHDB’s neonicotinoid activity, visit cereals.ahdb.org.uk/neonics