SUMMARY The decimal code for the growth stages of cereals devised by Zadoks, Chang & Konzak (1974) is reproduced here with expanded definitions of some of the descriptive phrases and stylised drawings of selected stages of wheat, barley and oat plants.

SUMMARY Fifteen growth stages of annual dicotyledonous weeds are described and illustrated, showing the progression from emergence to senescence. These stages have been agreed following widespread consultation amongst the member organisations of the British Crop Protection Council. Stages are defined in terms of leaf number, plant size and floral development. They are intended for use in the field by farmers, growers and their technical advisers, on herbicide labels and in advisory publications. They are also of value in research, aiding the description of weeds in field and glasshouse experiments.