Assessing the impact of the restrictions on the use of neonicotinoid seed treatments

Summary

The questions included in the planting survey were asked to help assess the potential impact of the restrictions on the use of neonicotinoid seed treatments. Approximately 11% of respondents said they would have planted additional areas of WOSR if neonicotinoid seed treatments had been available. When scaled up to represent the whole of England, the difference between the area farmers intended to plant and did plant for harvest 2015 was approximately 38,000 ha. The total area that might have been planted if neonicotinoid seed treatments had been available would have been equivalent to a 5% increase over the area of OSR harvested in 2014 (both winter and spring varieties). This compares to the fall of 1% shown in the AHDB/HGCA Winter Planting Survey. 

These findings demonstrate that the restriction on neonicotinoids did have an impact on the 2014 WOSR plantings

Approximately 5% of the original planted area was reported to have been lost to adult CSFB. However, about 1.5% of area was reported to have been successfully replanted as of 1 December 2014. This loss of 3.5% is theoretically equivalent to approximately 22,000 ha across England. The restriction on the use of neonicotinoid seed treatments could potentially have affected the crop losses recorded as of 1 December 2014 because of the limited control options available to reduce the damage to seedlings caused by early attacks by adult CSFB. The only chemical control option during the main emergence period was a pyrethroid insecticide, to which there is evidence of resistance in CSFB in England.

The area lost reported here is that up to 1 December 2014 and is only accountable to adult CSFB. It, therefore, does not take into account any crop losses which may subsequently occur from CSFB larvae later in the season. Further work is continuing to assess the impact of CSFB larvae damage to WOSR.