EFFICIENCY OF ALACHLOR DIURON MIXTURE ON WEED-CONTROL IN IRRIGATED COTTON/

In order to investigate the efficiency of alachlor/diuron doses (tank mixture) against weeds and their effect on irrigated annual cotton a f ield trial was placed in Pombal-PB, Brasil, in 1990. The alachlor/diur on doses (expressed in kg/ha of active ingredient) were: (0,6 + 1,0), (1,2 + 1,0), (1,8 + 1,0), (1,2 + 1,8), (1,2 + 1,2), (0,6 + 1,2) all in pre-emergence, control with cultivation and control without cultivati on. The experiment was set out in a ramdomised complete block with 5 r eplications. The results showed that: 1) the herbicide mixtures were s elective to cotton plants and effective on controlling weeds for a per iod superior to 60 days after emerging, 2) the herbicide treatments di d not affect consistently phenological cotton plant characteristics. T he component production and intrinsic fiber characteristics and 3) the highest mean value of ''number of bolls'' and yield were obtained by the alachlor/diuron dose (1,2 + 1,2) which did not differ from the oth er treatments except for the lowest dose (0,6 + 1,0) and control witho ut cultivation.