Critical period for weed control in leek (Allium porrum L.)

Field studies were conducted in Mersin, Turkey, in 2002 and 2003 to determine the critical period for weed control in leek and to investigate the effects of weed interference on weed biomass. The critical period for weed control in leek based on a 5% acceptable yield loss level was calculated by fitting logistic and Gompertz equations to relative yield data. Total fresh biomass of weeds increased as the duration of weed infestation increased. The beginning of the critical period for weed control was 7 days after transplanting in 2002 and 13 days after transplanting in 2003. The end of the critical period for weed control was 85 days after transplanting in 2002 and 60 days after transplanting in 2003. Results of this study suggest that leek should be kept weed free between 7 days after transplanting and 85 days after transplanting to avoid yield losses in excess of 5%.