Evaluation of Post-emergence Herbicides in Sugar Beet

The efficacy of iran produced chloridazon 50% sc (csc) was compared with its original formulation, 80% wp (cwp), the formulation which has been registered to use in sugar beet fields in iran. the present study was conducted in three different provinces of iran, including tehran, khorasan and khuzestan during 2001. the treatments consisted of the application of cwp at 3.2 and 4 kg ai ha1 , csc at 2.5 and 3 kg ai ha1 , tank mixed application of cwp or csc at above mentioned rates with desmedipham (dmp) at 0.8 kg ai ha1, phenmedipham 6% + desmedipham 6% + ethofumisate6% (pde) at 0.7 kg ai ha1. all herbicides were applied as post-emergence when sugar beet was at 4-leaf stage. weedy and weed free checks were also included. in tehran experiment, application of cwp at 3.2kg ai ha1 plus dmp or pde resulted in the best control of amaranthus retroflexus. in khorasan , csc,cwp and csc + dmp controlled this weed better than other treatments. in the recent experiment, csc and cwp, alone or mixed with dmp, controlled a. albus significantly. the effect of csc at 2.5kg ai ha~!+ dmp, cwp at 4 kg ai ha1* dmp, and pde at 0.7 kg ai ha'1 on chenopodium album was better than that of other treatments. the treatments had no significant effect on malva sylvestris, compared with weedy check. the best control of carthamus oxyacantha and fumaria officinalis was achieved by application of cwp at 3.2 kg ai ha1, and csc at 3 kg ai ha-1+ des. beta maritima was more efficiently controlled using csc at 3 kg ai ha!and csc at 3 kg ai ha-1+ des. the results indicated that for the control of broad leaf weeds in sugar beet fields, the new formulation of chloridazon, (sc), was similar to the original formulation (wp).