THE USE OF A LOW DOSE OF ATRAZINE ALONE AND IN MIXTURES WITH OTHER HERBICIDES IN THE MAIZE CROP

Summary. Linuron, 2,4‐D‐aniine, propachlor, pyriclor and cypromid, singly and mixture with atrazine, were compared with atrazine and fluromidine alone for effectiveness of weed control in maize on Oxford clay soil. Pre‐emergence applications were made under wet conditions and atrazine, even at 0·28 kg/ha a.i. gave an excellent control of three main weeds, Stellaria media, Veronica spp. and Polygonum aviculare, and at 0·56 kg/ha also killed Aethusa cynapium. Fluromidine was comparable with atrazine, but linuron,2,4‐D‐amine, propachlor and pyriclor were less effective. Post‐emergence treatments were less satisfactory. High doses of atrazine were needed for good weed control. Acynapium was resistant to pyriclor and cypromid and P. aviculare to fluromidine. 2,4‐Daminewas ineffective, but atrazine/2,4‐D‐amine mixtures were more effective than the individual components for the control of P. aviculare. Pyriclor, at 0·56 kg/ha pre‐emergenceand cypromid at 2·24 kg/ha post‐emergence directly reduced the yield of the crop. Utilisation de I'atrazine à faible dose, seule et en mélange avec d'autres herbicides, dans les culturesde maïs