investigating efficiency of some herbicides to control weeds in tobacco fields (nicotiana tabacum)

efficacy of many herbicides to control broad- and narrow-leaf weeds (grass weeds) in tobacco fields of mazandaran and guilan provinces was investigated. the experiment was randomized complete blocks design in four replications and the following treatments: eptam (eradicane 82% ec) at 6 l.ha-1 which incorporated pre-planting (ppi), trifluralin (treflan 48% ec) at 2 l/ha ppi, cycloate (roneet 72.7% ec) at 5 l/ha ppi, pendimethalin (stomp, 33% ec) at 5 l.ha-1 pre-emergence, alachlor (lasso 48% ec) at 5 l.ha-1 pre-emergence., oxyfluorfen (goal 24% ec) at 2 l.ha-1 pre-emergence., oxadiargyl (top star 30% ec) at 2 l.ha-1 pre-emergence., rimsulfuron (titus 25% df) at 50 gr.ha-1+ 2% surfactant (cytogate) post-emergence, haloxyfop-p- methyl (galant super 10.8% ec) at 0.75 l/ha post-emergence, cycloxydim (focus 10% ec) at 2 l.ha-1. post-emergence, weed-less check. results showed that weed control in tobacco fields increases yield and quality of tobacco and iconsequently farmers' income. for chemical control of weeds in tobacco fields, if the problem of cyperus spp. exists, eradicane herbicide is recommended as a pre-planting incorporated herbicide. if no cyperus spp. is present, treflan is suggested to be sprayed, because, it controls broadleaf weeds better. if grass weeds cause problem, one of the two graminicides, galant super or focus, may be sprayed before stem extension.. one or two mechanical weeding also may follow, as needed.