Allelopathic effects of two important exotic weeds, Ageratum houstonianum Mill. and Chromolaena odorata (L.) R.M. King & H. Rob. on some crop plants

Weeds are undesirable plants growing in an area where they are not wanted. These are generally highly competitive and adaptable to very wide environmental conditions. While competing with crop plants for light, nutrient and moisture contents of the soil, many weeds have allelopathic effects on crop plants. The present work investigated the allelopathic effects of two dominating exotic weeds Ageratum houstonianum Mill. and Chromolaena odorata (L.) R.M. King & H. Rob. on (i) Sesame Sesamum indicum L. of Pedaliaceae, (ii) Mustard Brassica nigra (L.) K.Koch of Brassicaceae, (iii) Lai-patta/Mustard green Brassica juncea (L.) Czern. of Brassicaceae, and (iv) Radish Raphanus raphanistrum subsp. sativus (L.) Domin. of Brassicaceae, which showed the strong derogative effects on crop plants.