17 A. Javaid T. Riaz Journal of Animal and Plant Sciences JAPS 20072007/08/01 17 4 NA 1018-7081 NA <p>Distribution of aggressive alien weed species Parthenium hysterophorus L. was studied in district Okara, Pakistan during September-October 2006. Eight waste and grazing lands, each of about 1 ha, were selected randomly in different parts of district Okara with 3&ndash;8 km distance between the two adjacent localities. P. hysterophorus was found in 7 out of 8 studied sites exhibiting 88% prevalence. The absolute and relative frequencies of P. hysterophorus were 36% and 2.56%, and absolute and relative densities were 0.56 and 2.71%, respectively. The frequency and density of P. hysterophorus were higher than 28 and 30 out of 38 weed species, respectively, identified from the studied areas.</p> Alien weed, distribution, Okara, Pakistan, Parthenium hysterophorus Pakistan Agricultural Scientists Forum https://thejaps.org.pk/AbstractView.aspx?mid=2007-JAPS-409