Parthenium weed's botanical name is Parthenium Hystrophorous. It is a herbaceous plant, and a native of Tropical America. Parthenium weed is locally called Congress or Gajjar Grass. It is an annual herb and has a deep taproot and erect stem, which becomes woody with age. Parthenium weed leaves are deeply lobed. It is pale green in colour and has soft hair.

Parthenium weed flower is creamy white in color. The weed has a large number of stems. It has small (1-2mm long) black seeds with white scales. They are not visible to the naked eye. It has been declared noxious in America, Australia, India and many other countries especially those having tropical climates (Parson & Euthbert Son, 1992).

Parthenium weed germinates in spring and summer. It dies around autumn. It can however; grow any time of the year, if conditions are suitable for its growth and usually grows near water points. It can set in four weeks after germination and flowering continues till the plant dies. It is a prolific producer of seed and can produce upto one-lac seeds per plant. In India, it exists virtually everywhere North, South, East or West.