A second survey of cereal weeds in central southern England

A survey of grass weeds of cereals in central southern England made in 1981 was repeated in 1982 between 28 June and 23 July. Dicotyledonous weeds were also assessed in 1982. A total of 1021 fields were surveyed, 702 in winter wheat. 198 in winter barley and 121 in spring barley. A total of twenty-four grass weeds were found and their levels of infestation were scored. The most frequently found grass weeds were the same as in 1981. In all cereals combined, these were Elymus (Agropyron) repens in 35% of fields, Avena fatua in 32%, Alopecurus myosuroides in 26% and Poa trivialis in 24%. Sixty-three species of dicotyledonous weeds were recorded and of these, eighteen species occurred in 2% or more of fields. The eight most frequent were Viola arvensis, Galium aparine, Stellaria media, Myosotis arvensis, Polygonum aviculare, Convolvulus arvensis, Bilderdykia (Polygonum) convolvulus and Lamium purpureum. Most species were fairly uniform in distribution, but Galium aparine, Convolvulus arvensis and Cirsium arvense were most frequent in the east while Viola arvensis was least frequent there. The cereals varied in weediness, 32% of winter barley, 23% of spring barley and only 7% of winter wheat fields had no weeds recorded.