CSFB adults feed on the foliage of emerging crops and can threaten establishment. They lay their eggs at the base of plants and the larvae mine the petioles from mid-October before moving into the stems. Losses due to CSFB in 2016/17 were estimated at 9% of the national crop (>33,000 ha) by April (Wynn et al, 2017). In the 2015/16 Fera Crop Monitor pest survey CSFB larval populations were higher than in any previous year (Collins, 2017)
An objective of the project is to assess non-chemical options for CSFB control. This includes investigating whether grazing or defoliating OSR during the winter can control CSFB larval populations. Defoliation in the winter prior to stem elongation has been shown to have a negligble impact on yield.
Our work assessed the impact of defoliation at three timings on larval populations and yield. Results showed that defoliation resulted in significant reductions in larval numbers of up 60% compared to an undefoliated control.
Further work is planned to better understand the control method, including ADAS trials and farmer-led work.
To find out more please contact Sacha.White@adas.co.uk
Pest Management and Entomology