Survey of the presence of wild oat and blackgrass in parts of the United Kingdom

Summary: The survey was carried out over an area representing about 47% of the cereal acreage of the United Kingdom. Estimates of the acreage of fields containing wild oat ( Avena fatua L. and A. ludoviciana Dur) ranged from 15% (Northern Ireland) to 74% (England, South West Region). The degree of infestation over the total acreage was 58%‘light’, 34%‘medium’, and 8%‘heavy’. Blackgrass ( Alopecurus myosurodies Huds.) was found only in the central and southern regions, estimates of the infested cereal field acreage ranging from 2% (Wales) to 23% (South East England). Nine per cent of the fields were rogued for wild oat. On average, only 10% of the infested acreage received herbicide treatment for wild oat and blackgrass though, in some regions, up to 23 % was treated. The timing of treatment and the herbicide used were recorded. Information on the extent and type of herbicide used for broad‐leaved weeds was also recorded. Data on sowing dates of the crops, the previous cropping, previous infestations, the soil type and the state of field drainage were obtained and were correlated with the incidence of wild oat and blackgrass where relevant.